Download 6. Optimizing meadow bird protection

2012
http://www.drom.nl/533
Optimizing meadow bird
protection in the Netherlands:
Focusing on Black-tailed Godwit, Common Redshank,
Eurasian Oystercatcher and Northern Lapwing
http://www.natuurbericht.nl/?id=2633
Name: Mark Eugster
Student number: 3242862
Supervisor: dr. Jos Dekker
26-11-2012
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Abstract
Meadow birds encompass a wide range of bird species showing unique yearly population trends. The
four focus species in this essay, Black-tailed Godwit (Limosa limosa), Common Redshank (Tringa
totanus), Eurasian Oystercatcher (Heamatopus ostralegus) and Northern Lapwing (Vanellus vanellus),
show relatively negative yearly population trends and can therefore not be seen as a representative
group for meadow birds in general. These negative population trends and current Dutch meadow bird
populations are the result of changes in the past. The Dutch polder landscape, with its high meadow
bird population densities, is a recent phenomena. Meadow birds originally inhabited coastal areas,
natural grasslands, natural steppes and wetlands and expanded their range into agricultural grasslands
when agriculture started to develop. Initially, agriculture was extensive and had a positive effect on
meadow bird population densities. In more recent times, intensification, especially CAP-driven after
World War II (1957), turned out to negatively influence meadow bird populations. To counteract
declines in Dutch meadow bird populations, protection in the Netherlands started, on a voluntary
basis, with individual nest protection and the alteration of farming practices. It took until 1975
(Relatienota) before the first regulation considering meadow bird protections was introduced in the
Netherlands. This was relatively early, since the EU did only develop regulation in 1992 (Regulation
2078/92). Ever since the introduction of regulation, there have been changes. In spite of these changes,
that can be considered improvements, the current population trends of the four focus species are
negative. Since considerable parts of the Dutch meadow bird populations are restricted to agricultural
areas, most protection measures aim at reducing the negative effects of agricultural practices. By
offering a variety of meadow bird protection packages, the Dutch government aims at promoting
mosaic management. It turns out that the removal of a single threat opposing Dutch meadow bird
populations is insufficient to guarantee stable meadow bird populations. Because predation is
responsible for a large part of the losses of nests and chicks, measures aiming at minimizing predation
will have a relatively large positive effect on the reproductive output of Dutch meadow bird
populations. An MCA demonstrates that an optimization of mosaic management, combined with
measures to tackle predation, is the most effective way of protecting Dutch meadow bird populations.
Since predation levels and the set of predators responsible for predation vary throughout the
Netherlands, a provincial based mapping system should be developed in order to advice farmers on
specific measures that could be taken to tackle predation. The predicted need for future agricultural
intensification, in order to fulfill the future global food demand, make that the Netherlands are
unlikely to house meadow bird population densities comparable to those in the pre-agricultural
intensification period.
Preface
The master’s thesis laying in front of you is part of the master’s programme Environmental Biology at
Utrecht University, and more specific the Ecology and Natural Resource Management track. All
information reported is based on a literature study that took place during a period of ten weeks, halftime. The main goal of this thesis is to give insight in the current protection measures concerning
Dutch meadow bird populations and to give ideas on the optimization of these protection measures.
I hereby want to thank my supervisor, dr. Jos Dekker, who gave me the freedom to work out
my own ideas and supported me with recommendations from his point of view. The temporary
discussion meetings resulted in new insights to improve the quality of the final result.
Mark Eugster (3242862)
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Contents
Introduction ............................................................................................................................................. 5
1. Meadow birds – An overview ............................................................................................................. 8
1.1 A case of classifying.......................................................................................................................... 8
1.2 A broad term...................................................................................................................................... 9
1.3 Good performers/bad performers .................................................................................................... 10
2. Meadow birds in the Netherlands ...................................................................................................... 14
2.1 ‘Meadowbirdification’..................................................................................................................... 14
2.2 The Netherlands, a meadow bird country........................................................................................ 14
2.3 CAP-driven agricultural intensification .......................................................................................... 15
2.4 Balancing disturbance ..................................................................................................................... 16
3. Meadow bird protection regulation in the Netherlands ..................................................................... 20
3.1 Towards national meadow bird protection regulation – The Relatienota........................................ 20
3.2 Towards European meadow bird protection regulation – Regulation 2078/92 ............................... 21
3.3 Towards collective meadow bird protection – Programma Beheer................................................. 21
3.4 Towards current regulation – SNL .................................................................................................. 22
3.5 Future regulation – CAP greening and the Natuurakkoord ............................................................. 22
4. Threats ............................................................................................................................................... 25
4.1 Habitat loss, fragmentation and disturbance ................................................................................... 25
4.2 Grazing and mowing ....................................................................................................................... 27
4.3 Manuring ......................................................................................................................................... 28
4.4 Desiccation ...................................................................................................................................... 30
4.5 Vegetation composition ................................................................................................................... 31
4.6 Predation.......................................................................................................................................... 34
4.7 Overwintering.................................................................................................................................. 38
4.8 Threats – An overview .................................................................................................................... 39
5. Protection measures ........................................................................................................................... 41
5.1 Voluntary meadow bird protection .................................................................................................. 41
5.2 Agri-environment schemes .............................................................................................................. 42
5.3 Mosaic management ........................................................................................................................ 44
6. Optimizing meadow bird protection .................................................................................................. 49
6.1 Ranking threats ................................................................................................................................ 49
6.2 Optimizing current protection measures? ........................................................................................ 50
6.3 Optimizing establishment ................................................................................................................ 51
6.4 Optimizing current protection measures ......................................................................................... 52
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6.5 Additional protection measures ....................................................................................................... 53
6.6 Site selection.................................................................................................................................... 54
6.7 Multi-Criteria Analysis (MCA) ....................................................................................................... 55
7. Discussion and conclusion ................................................................................................................ 58
8. Literature ........................................................................................................................................... 61
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Introduction
The term meadow birds is derived from the Dutch word ‘weidevogels’ and was introduced by Thijsse
1913. (Beintema 1983; Dekker 2009). The term has been used ever since, but a clear definition is still
lacking. Meadow birds, according to Beintema 19912, can be defined as birds breeding in agricultural
grassland. This seems obvious, and most definitions being used come to the same thing. Therefore, the
problem concerning the term meadow birds is not so much the definition itself, but the set of birds
termed meadow birds. Dekker 2009 showed that, in the case of the Netherlands, a total of 30 bird
species can be considered meadow birds, according to literature. Furthermore, Dekker 2009 showed
that the number of birds termed meadow birds varies from 4-21 in the Netherlands. This great
variation in the set of bird species termed meadow birds in literature has implications for results
presented and conclusions being drawn, since every meadow bird species has unique (habitat)
preferences. These preferences will largely determine current population trends. It therefore is
necessary to strictly define the group of bird species termed meadow birds or to clarify that only a
select group of meadow birds species will be used in a research, or, in this case, a thesis.
In this thesis, the term meadow birds encompasses a group of four species (unless stated
differently): Black-tailed Godwit (Limosa limosa), Common Redshank (Tringa totanus), Eurasian
Oystercatcher (Heamatopus ostralegus) and Northern Lapwing (Vanellus vanellus) (figure 1). This
because most literature focuses on this set of species and because of the significant breeding
populations of some of these species in the Netherlands. For example, 40-50% of the European Blacktailed Godwit population and 30-40% of the European Eurasian Oystercatcher population breed in the
Netherlands (Teunissen et al. 2006).
The large numbers of Black-tailed Godwit and Eurasian Oystercatcher breeding in the
Netherlands show the importance of the Netherlands as a ‘meadow bird country’. Of course meadow
birds are not restricted to the Netherlands, for, for example, counties in North- (Common Snipe i.e.
Gallinago gallinago and Marbled Godwit i.e. Limosa fedoa) and South America (Southern Lapwing
i.e. Vanellus chilensis) and European countries besides the Netherlands (Russia harbors significant
breeding populations of Black-tailed Godwit i.e. Limosa limosa) also harbor significant meadow bird
populations (Beintema 19912; Stroud et al. 2004). What makes the Netherlands unique are, next to the
large breeding populations of certain species, the high densities and great variety of meadow birds and
the fact that these birds are nowadays mostly restricted to agricultural grasslands (Beintema 1983;
Beintema 19912; Beintema et al. 1995; Swagemakers et al. 2009; Terwan et al. 2002).
Until about 50 years ago, the status of the Netherlands being an important meadow bird
country was taken for granted (Beintema et al. 1995; Brouwer 2005). People considered meadow birds
part of the Dutch polder landscape (Beintema et al. 1995; Brouwer 2005). This attitude towards
meadow birds stands in stark contrast with the current situation. Most commonly, media show
negative meadow bird population trends throughout the Netherlands. Therefore, the general view on
the state of meadow bird populations is negative (Dekker 2009). Again, the current status of Dutch
meadow bird populations depends on the bird species considered meadow birds, but factors like the
area observed, the period of observation and the reference population further determine population
trends (Dekker 2009).
Due to the importance of the Netherlands being a meadow bird country, the Netherlands have
a moral obligation to protect meadow bird populations, since a decline in Dutch meadow bird
populations would mean a serious decline in the (Western) European populations of these species
(Teunissen et al. 2006). The goal of this thesis is to answer the question: ‘What is the most effective
way of protecting meadow birds in the Netherlands?’ As said before, the focus will be on four species,
but a more general part will be presented first.
The general part will start answering the question: What are meadow birds? Different studies
study different species. Do all species show comparable population trends or are there differences?
And how do the populations of the four focus species of this essay perform recently? After this, the
history of Dutch meadow bird populations will be discussed. How have meadow bird populations
developed through time in the Netherlands? What factors have been affecting their distribution? Also,
the history of regulation considering meadow bird protection will be discussed. What was the first
regulation considering meadow bird protection and how did regulation evolve through time?
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After this, the thesis will focus on the four species mentioned earlier. Which are the main
threats considering meadow bird populations, what are the measures taken to protect the populations
and how effective are these measures? The effectivity of current measures might be optimized. How
can this be achieved? Finally, the main question, what is the most effective way of protecting meadow
bird populations in the Netherlands, will be answered. A Multi-Criteria Analysis (MCA) will be used
for this. A literature study forms the basis for this thesis.
Figure 1: In this thesis, the term meadow birds encompasses four species (unless stated differently): Black-tailed
Godwit (Limosa limosa) (A), Common Redshank (Tringa totanus) (B), Eurasian Oystercatcher (Heamatopus
ostralegus) (C) and Northern Lapwing (Vanellus vanellus) (D).
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1
Meadow birds –
An overview
http://www.avibirds.com/euhtml/Northern_Lapwing.html
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1. Meadow birds – An overview
Before being able to say anything about meadow birds, the term needs to be clarified. This chapter
will therefore focus on the question: What are meadow birds? Different researchers and institutes
consider different bird species to be meadow birds. What causes these differences to appear? And
what do differences in the bird species considered to be meadow birds mean for the general state of
the Dutch meadow bird population? How are the four focus species, Black-tailed Godwit (Limosa
limosa), Common Redshank (Tringa totanus), Eurasian Oystercatcher (Heamatopus ostralegus) and
Northern Lapwing (Vanellus vanellus) performing and does this reflect the general trend?
1.1 A case of classifying
Since Thijsse 1913 first used the term meadow birds in literature, it has been used ever since (Dekker
2009). Until now, though, there is no consensus on which bird species can be considered meadow
birds. The definition of meadow birds by Beintema 19912 states that meadow birds can be defined as
birds breeding in agricultural grasslands. Most definitions being used come to the same thing.
Therefore, the problem concerning the term meadow birds is not so much the definition itself, but the
set of birds termed meadow birds. Dekker 2009 showed that a total of 30 bird species can be
considered Dutch meadow birds, according to literature. Furthermore, Dekker 2009 showed that the
number of bird species termed (Dutch) meadow birds varies from 4-21 in different studies.
Beintema et al. 1995 classified meadow birds into two groups, the primary meadow birds and
the secondary meadow birds. The secondary meadow birds consist of species that breed in agricultural
grasslands only locally or occasionally. The primary meadow birds consist of species that are
restricted to agricultural grasslands for their breeding success. This definition of primary meadow
birds suggests that there are species that, in the Netherlands, can only be found breeding in agricultural
grasslands. In fact, this is not the case. No bird species in the Netherlands is totally restricted to
agricultural grasslands for nesting and raising chicks. This because birds that are nowadays recognized
as being meadow birds, originally colonized coastal areas, natural grasslands, natural steppes and
wetlands and can still be found there (Beintema et al. 1995; Cramp et al. 1983). Because of this, the
term primary meadow birds is not as strict as it seems and species are reckoned among the primary
meadow birds if a ‘considerable part’ of the population is restricted to agricultural grasslands for their
breeding success. The term considerable part can be interpreted in different ways, causing differences
in the set of bird species that are termed meadow birds by different researchers and institutions.
(Beintema et al. 1995)
Differences in the interpretation of the terms primary meadow birds and secondary meadow
birds causes differences in the number of bird species termed meadow birds, as shown by Dekker
2009. Regional differences in bird communities can also play a role in explaining these differences.
Beintema et al. 1995 used a couple of species to clarify this, one of them being Ruff (Philomachus
pugnax). This species nowadays is restricted to small parts of the Netherlands (Friesland, Groningen,
Noord-Holland) (Vogelbescherming 20121). According to Koffijberg et al. 2007, Ruff (Philomachus
pugnax), but also Corn Bunting (Milaria calandra), can be expected to disappear from the Netherland
in the near future. Also, certain duck species (e.g. Garganey i.e. Anas querquedula) and Eurasian
Curlew (Numenius arquata) cannot be found throughout the Netherlands, since some provinces lack
the presence of these species (Beintema et al. 1995). This shows that, if only local bird species are
assessed, different sets of birds will be termed meadow birds in different parts of the Netherlands. The
fact that Ruff (Philomachus pugnax) is considered to be a meadow bird species nowadays says more
about the historical status of Ruff populations in the Netherlands, than it does about the current status
of Ruff (Philomachus pugnax) populations (Beintema et al. 1995). This shows that the term meadow
birds is not a fixed term. As said, Koffijberg et al. 2007 stated that Ruff (Philomachus pugnax) and
Corn bunting (Milaria calandra) can be expected to disappear from the Netherlands. Therefore, these
species will most likely no longer be part of the future Dutch meadow bird community. On the other
hand, species like Graylag Goose (Anser anser) and Barnacle Goose (Branta leucopsis) are rapidly
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expanding their range into Dutch agricultural grasslands and might therefore become part of the Dutch
meadow bird community in the near future (Koffijberg et al. 2007).
Another way of classifying meadow bird species that is described by Beintema et al. 1995 is
classifying based on rarity. This also results in two different groups, the critical meadow birds and the
non-critical meadow birds. Like the classification described above, this way of classifying can be
interpreted in different ways, depending on what is termed critical and non-critical. Also, the location
and the period of observation can bias this classification method. Ruff (Philomachus pugnax), again,
can illustrate this. Nowadays, Dutch Ruff (Philomachus pugnax) populations are limited and Ruff
(Philomachus pugnax) can therefore be considered a critical meadow bird species (EL&I 2012). On
the other hand, Ruff (Philomachus pugnax) used to be a more common bird species in past times
(EL&I 2012). This shows that Ruff (Philomachus pugnax) made a shift from being a non-critical
meadow bird species towards being a critical meadow birds species in more recent times. Also,
regional differences in bird communities can cause one species to be termed critical in one area and
non-critical in another area, if the classification is based on local population data. To discriminate
between different levels of population decline or increase, the terms critical and non-critical can be
split up to get a clearer picture of the current state of Dutch meadow bird populations. This would, for
example, result in Ruff (Philomachus pugnax) being a very critical species and Black-tailed Godwit
being a critical species (EL&I 2012). (Beintema et al. 1995)
1.2 A broad term
According to Beintema et al. 1995, the primary meadow birds consist of: Northern Lapwing (Vanellus
vanellus), Black-tailed Godwit (Limosa limosa), Eurasian Oystercatcher (Haematopus ostralegus),
Eurasian Curlew (Numensius arquata), Common Redshank (Tringa totanus), Common Snipe
(Gallinago gallinago), Ruff (Philomachus pugnax), Northern Shoveler (Anas clypeata), Tufted Duck
(Aythya fuligula), Garganey (Anas querquedula), Meadow Pipit (Anthus pratensis), Eurasian Skylark
(Alauda ervensis) and Yellow Wagtail (Motacilla flava). The four focus species of this thesis are so
considered to be primary meadow birds. Since considerable parts of the Dutch populations of these
bird species are restricted to agricultural grasslands, it seems likely that the primary meadow bird
species are more sensitive to the disturbance of agricultural grasslands than the secondary meadow
bird species, because these species have a broader habitat range (Swagemakers et al. 2009; Terwan et
al. 2002).
The four focus species of this thesis, Black-tailed Godwit (Limosa limosa), Common
Redshank (Tringa totanus), Eurasian Oystercatcher (Heamatopus ostralegus) and Northern Lapwing
(Vanellus vanellus) (figure 1) are so called waders, characterized by their long legs. This group of
meadow birds can be seen as ‘hard core’ meadow birds (Beintema et al. 1995). Together with ducks,
passerines and terns/rails, they form both primary and secondary meadow birds (Beintema et al. 1995).
Table 1 gives an overview of the four different groups making up meadow birds. The species listed are
the Dutch meadow birds according to Beintema et al. 1995. A (2) indicates a secondary meadow bird
species, whereas species lacking this (2) are primary meadow birds.
Table 1 gives an idea of the great variety of bird species that can be considered meadow birds.
The different groups all have different characteristics. For example, ducks are aquatic birds, whereas
passerines are not. Furthermore, waders are relatively large birds compared to passerines. These
differences between the different groups making up meadow birds clarify that all groups will have
different demands when it comes to their habitat. Also, differences exist within groups. Beintema 1983
showed this for different meadow bird species within the wader group. This variation between the
different groups making up meadow birds and also within these groups, indicates the difficulty of
drawing general conclusions on the current state of Dutch meadow birds in general.
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Table 1: The primary and secondary (2) Dutch meadow bird species according to Beintema et al. 1995.
Wader
Black-tailed Godwit
Northern Lapwing
Eurasian Oystercatcher
Eurasian Curlew
Pied Avocet (2)
Common Redshank
Common Snipe
Ruff
Ducks
Northern Shoveler
Garganey
Gadwall (2)
Tufted Duck
Eurasian Teal (2)
Mallard
Common Shelduck (2)
Passerines
Eurasian Skylark
Meadow Pipit
Yellow Wagtail
Winchat (2)
Corn Bunting (2)
Terns/Rails
Corn Crake (2)
Common Tern (2)
Black Tern (2)
Grey Partridge (2)
Common Quail (2)
Eurasian Coot (2)
Black-headed Gull (2)
European Stonechat (2)
1.3 Good performers/bad performers
Figure 2 shows yearly population trends of 19 meadow bird species according to ‘Weidevogelbalans
2010’ (SOVON 2010). Again, these 19 species clarify the variation in the set of birds considered
meadow birds by different researchers and institutions, since these 19 species are a considerably lower
amount than the 28 species listed in table 1. When figure 2 is observed, first of all a wide variation in
the performance levels of different bird species becomes clear. During recent years (2004-2008), the
performance levels range from a yearly population increase of about 13% (Eurasian Teal i.e. Anas
crecca) to a yearly population decrease of about 7% (Eurasian Oystercatcher i.e. Haematopus
ostralegus). This demonstrates the different demands that different meadow birds have when it comes
to their habitat, mentioned earlier. Also, the different groups making up meadow birds are shown to
perform differently in figure 2. The ‘good performers’ shown in the upper end of the figure consist
mostly of duck species, whereas the ‘bad performers’ shown at the bottom of the figure consist mostly
of wader species.
When short-term trends (2004-2008) are compared to long-term trends (1990-2008), it
becomes clear that yearly population trends have been shifting over the last two decades (figure 2).
When the trends for the four focus species of this thesis are compared, the short term trends seem to be
more negative than the long term trends. For Common Redshank (Tringa totanus) this even means a
transition from a long-term positive population trend to a short-term negative population trend. This
negative short-term population trend (about 3%) is relatively small compared to that of the other three
species, of which yearly declines are about 6-7%.
The differences in population performance levels, shown in figure 2, between the different
groups making up meadow birds, within the different groups making up meadow birds and between
different observation periods, indicate the need of clarity when it comes to the term meadow birds.
Dekker 2009 mentioned spatial variation as an additional factor that could influence the performance
of meadow bird species. This is explained by making a comparison between agricultural and nonagricultural areas. Differences in e.g. management practices between these different areas cause
conditions to vary locally, causing meadow bird populations trends to vary on a spatial scale. Figure 2
gives no insight in the effect of this factor, since the yearly performance levels are national scale
levels. In case of the four species Black-tailed Godwit (Limosa limosa), Common Redshank (Tringa
totanus), Eurasian Oystercatcher (Heamatopus ostralegus) and Northern Lapwing (Vanellus vanellus)
(figure 1), the general trend seems to be negative, with the lowest population performance levels
during more recent years (2004-2008). Because the most recent data was gathered during the period
2004-2008, the current situation might be slightly different. Data by SOVON 2012, shown in figure 3,
suggests that the performance levels of three of the focus species went up slightly after 2008. For the
Eurasian Oystercatcher (Heamatopus ostralegus) this seems to not be the case. The amount of
breeding pairs of the other species seems to recover. However, periods of recovery might only be
temporal. One can only speak of a positive population trend when recovery is continuous over a longer
time span.
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Figure 2: Yearly population trends of 19 meadow bird species, according to the SOVON 2010. Trends are divided into
long-term trends (1990-2008) and short-term trends (2004-2008).
Figure 3: The amount of breeding birds for the four focus species of this thesis. Lines indicate index-lines, with 1990
being the reference year. Source: SOVON 2012.
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It is, thus, hard to give an exact idea on what meadow birds are. The definition of meadow birds by
Beintema 19912 states that meadow birds can be defined as birds breeding in agricultural grassland.
Most definitions being used come to the same thing, but it is hard to draw general conclusions on the
current state of Dutch meadow birds in general, since the species that can be considered meadow
birds are very diverse. The four main groups making up meadow birds are ducks, passerines,
terns/rails and waders. Differences between and also within these groups cause different species to
show unique yearly population trends. The four focus species in this essay show relatively negative
yearly population trends and can therefore not be seen as a representative group for meadow birds in
general. It therefore needs to be kept in mind that conclusions drawn in this thesis will not be general
conclusions regarding meadow birds, but only apply to a set of birds.
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2
Meadow birds
in the Netherlands
http://www.rspb.org.uk/wildlife/birdguide/name/b/blacktailedgodwit/index.aspx
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2. Meadow birds in the Netherlands
Now that it became clear that the term meadow birds is a very broad term, with different sets of
species being termed meadow birds by different researchers and institutions, the focus of this chapter
will be on meadow birds in the Netherlands. It will mainly focus on the question: How have meadow
bird populations developed through time in the Netherlands? Both the factors that influenced Dutch
meadow bird populations and the effects of these factors on the Dutch meadow bird populations will
be addressed.
2.1 ‘Meadowbirdification’
According to Beintema et al. 1995, real meadow birds do not exist, since these birds have been
colonizing the planet far before there were agricultural grasslands. This statement emphasizes that the
Dutch polder landscape with its high meadow bird population densities is a relatively recent
phenomena (Beintema 1983). Meadow birds originally colonized coastal areas, natural grasslands,
natural steppes and wetlands (Beintema et al. 1995; Cramp et al. 1983). Since natural grasslands
historically were very uncommon in the Netherlands, most populations must originally have colonized
foreign countries where these open habitats where abundant (Beintema et al. 1995). Another option is
that Dutch meadow bird populations originated from areas different than natural grasslands (natural
steppes or wetlands) and adapted to semi-natural grasslands more recently (Beintema et al. 1995).
During the Middle Ages, when the drainage of marshes in order to create arable land started,
meadow birds had the opportunity to expand their range. This because land obtained through the
drainage of marshes was located on peat soils (Beintema et al. 1997). At first, the arable land was
fertile and crop yields were high. As time passed by, the peat soils started to oxidize and shrink. At
first this was no big problem, since further drainage caused excessive water to be removed, keeping
the land arable. However, the shrinkage of peat soils eventually caused the surface of land obtained
through the drainage of marshes to become too low for more drainage to be possible. This was the
point at which the retained land was no longer arable. Farmers were forced to start using other farming
practices on these lands and used it as pastures for their cattle. The pastures were very fertile and wet,
ideal conditions for meadow birds (Beintema et al. 1987). Meadow birds therefore started to expand
their range into the newly formed semi-natural pasture lands. (Beintema et al. 1986)
Also, meadows started to evolve on peat soils covered with marine clay (Beintema et al.
1997). The combination of an upward capillary pressure of the underlying peat and the water retaining
capacity of marine clay made that conditions were too wet for arable crop production to take place.
Pastoralism therefore became the dominant farming practice in these areas and caused meadow birds
to expand their range into sea clay covered peatlands. (Beintema et al. 1986)
The areas described above are termed wet meadows and are predominantly found in the
Netherlands. Nowadays these areas are situated within the Dutch provinces Utrecht, Zuid-Holland
(drained marshes), Friesland and Noord-Holland (marine clay covered peatlands) (Beintema et al.
1997). Besides the drainage of wetlands, agricultural land was retained by the conversion of forests
and shrublands into semi-natural open ecosystems (Pain et al. 1997; Donald et al. 2002). Conditions in
the semi-natural areas described were more favorable than those present in natural habitats (Beintema
19912; Glutz von Blotzheim et al. 1977). As a consequence, the newly formed habitats housed
significantly higher meadow bird population densities than the natural habitats (Beintema 19912; Glutz
von Blotzheim et al. 1977). Beintema et al. 1995 referred to this process as ‘meadowbirdification’.
2.2 The Netherlands, a meadow bird country
As said, the newly formed semi-natural habitats named above were ideal meadow bird territory.
Beintema et al. 1995 stated that this is unique for the Netherlands, since open grassland ecosystems
can be found at numerous places in the world, but the high Dutch meadow bird densities are unique.
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According to Beintema et al. 1995, this can mostly be explained by the Dutch climate. This climate is
relatively wet and causes soils not to dry out during spring or summer. Additionally, as mentioned
above, current pastures are largely situated on drained marshes (peat soils) or marine clay covered
peatlands. These soils have a large water retaining capacity, which strengthens the effect of the Dutch
climate (Beintema et al. 1997). Together, this causes soils to be easily penetrable, thereby facilitating
the accessibility of soils for foraging meadow birds. This is important, for most adult meadow birds
depend mainly on the accessibility of soil dwelling invertebrates (Beintema et al. 1995).
Also, wet soil conditions cause plant development to slow down (Beintema et al. 1995). Since
agricultural activities (grazing, mowing, etc.) only start after the vegetation reaches a certain growth
stage, Dutch climate acted as a break on the start of agricultural activities during the past. This delay
provided meadow birds with a disturbance-free period, during which chicks could be raised safely.
The safety was, according to Beintema et al. 1995, enlarged by the fact that the density of predator
populations was low due to the frequent inundation of meadow bird habitat in winter.
Due to the favorable meadow bird conditions present in semi-natural habitats, the
disappearance of natural habitat did not have a big effect on meadow bird population. This
disappearance took place gradually, by the replacement of natural grazers by cattle, but could also be
more abrupt, for example through ploughing or re-seeding (Beintema 19912). Both can be considered
forms of habitat change (Beintema 19912). Since most habitat conversion took place in order to
generate more agricultural land, a considerable part was converted into agricultural grassland. This
conversion could even have a positive effect on meadow bird population.
The initial effect of agriculture, thus, was positive (Beintema 19912). Meadow birds could
expand their range into newly formed semi-natural habitats, where high population densities could be
housed (Beintema 19912; Glutz van Blotzheim et al. 1977). Furthermore, the conversion of natural
habitat into agricultural land was not harmful and could even have a positive effect on meadow bird
populations. On the other hand, the disappearance of natural habitat made meadow bird populations
rely on agricultural activity for their survival, because most natural habitats in the Netherlands
disappeared over time (Beintema 19912; Kleijn et al. 2003; Verhulst 2007). Meadow bird populations
were simply no longer capable of surviving without a certain degree of agricultural activity, since this
activity shaped their habitat (Beintema 1983; Beintema 19912; Kleijn et al. 2003).
2.3 CAP-driven agricultural intensification
During the last century, agriculture became subject to rapid change. The relatively extensive farming
practices, that had been dominant before and intensified only gradually, intensified at a more rapid rate
due to technical improvements among others (Baudry et al. 2003; Beintema 19912; Breeuwer et al.
2009; Donald et al. 2002; MacDonald et al. 2000; Robson 1997; Robinson et al. 2002; Verhulst 2007).
An important factor in this process is the so called Common Agricultural Policy (CAP) that was
initiated in 1957 by the European Commission (Donald et al. 2002; Verhulst 2004; Robson 1997;
Robinson et al. 2002). This policy aimed for an increase in agricultural production to ensure a stable
food supply and an increase in the financial state of Europe’s farmers (CAP Explained; Donald et al.
2002). The CAP stimulated mechanization to enhance productivity and guaranteed farmers a fixed
price for their products, stimulated the export of production surpluses on the world market through
financial funding and initiated import fees on foreign agricultural products to increase the situation of
Europe’s farmers (CAP Explained; Verhulst 2004; Donald et al. 2002).
Due to the CAP, the European farmers should have financially benefitted. This goal was only
partly met, because only a small part of the farmers that was present at the initiation of the CAP did
benefit. Most farms at that time were small, non-specialized farms that could not eligible for subsidy.
Because of this, the number of people working in the agricultural sector dropped by roughly 50%
between 1970 and 1997. Redistribution of land, specialization and the disappearance of smaller farm
led to drastic changes in Europe’s farmland structure, with a trend of farms scaling up and becoming
bigger. Farms did not only grow, farming practices evolved too. Stock levels increased, the use of
fertilizer and pesticides increased, drainage became more efficient, the amount of productive land
increased, etc. (Donald et al. 2002).
15
The transformation of Europe’s farming practices just described, caused the first goal of the
CAP, ensuring a stable food supply, to be realized. From the 1960’s onward, the food production in
Europe constantly increased (CAP Explained). During the 1980’s the food supply even exceeded
Europe’s demand for food for the first time (CAP Explained; Donald et al. 2002). The incentives of
the CAP aiming to increase the financial state of Europe’s farmers caused this overproduction to be
very expensive. Surpluses were either exported, with subsidies, or were stored (also subsidized) (CAP
Explained; Verhulst 2007). Either way, measures had to be taken to limit the production of individual
farmers. These measures were implemented during the 1980’s and 1990’s (CAP Explained). Farmers
were no longer allowed to produce unlimited goods. Strict quota’s were set and penalties for
overproduction were implemented (CAP Explained). Furthermore, the amount of livestock and the
area under production were restricted (CAP Explained). Together with some more market-based
restriction, the measures taken during the 1980’s and 1990’s resulted in the extensification of farming
practices. An example of this is the Dutch cattle density that dropped from 5.2 million cows in 1980 to
3.7 million cows in 2006, growing towards 3.9 million cows in 2009 (CBS 2012).
In contrast to the positive effect of early extensive farming practices on meadow bird
populations, the intensification of agriculture, that mainly took place after the initiation of the CAP, is
considered to be one of the causes of the deterioration of certain meadow bird populations in the
Netherlands over the last part of the 20th century and the first part of the 21st century (Baudry et al.
2003; Beintema 1983; Beintema 19912; Breeuwer et al. 2009; Donald et al. 2002; MacDonald et al.
2000; Robson 1997; Robinson et al. 2002; Verhulst 2007). The initial positive effect of agricultural
practices shows that meadow birds require a certain minimum agricultural intensity to be able to
bloom in agricultural areas (Beintema 1983). Since most meadow bird populations are currently
(partly) restricted to these areas, this minimum is necessary to keep semi-natural meadow bird areas
intact (Swagemakers et al. 2009; Terwan et al. 2002). On the other hand, the actual farming intensity
seems to negatively influence certain meadow bird population (Beintema 1983). Therefore, a balance
between the minimum farming intensity required to create suitable habitat and the maximum farming
intensity, above which meadow bird populations will be unable to survive, needs to be found.
According to Beintema et al. 1995, meadow birds will benefit most from an intensity level just below
the maximum threshold.
2.4 Balancing disturbance
Since the Dutch meadow bird population consists of a great variety of bird species, species-specific
characteristics cause different species to be able to cope with different disturbance levels. Every
species, thus, has its own range of disturbance levels it can cope with. It is important to realize that in
this case, Beintema et al 1995 took agricultural disturbance as an example. Of course there are
multiple disturbance factors and even agricultural disturbance cannot be seen as one factor, since
agricultural activity consists of multiple operations.
Because the range of disturbance levels a meadow bird species can cope with says something
about the conditions it can cope with, it can be seen as an indicator for resilience. According to
Beintema 1983, the main factor in determining the resilience of a species is the annual adult mortality.
One can imagine that, in order to maintain a bird population, the annual reproduction rate should be
sufficient to buffer this annual loss. Factors increasing the annual adult mortality or decreasing the
reproduction rate will therefore put a population under pressure. Beintema 1983 stated that there is a
positive correlation between the body weight of a bird and the annual chance of survival. This means
that, in order to maintain the population, smaller meadow bird species require a higher annual
reproduction rate. This could either be achieved by producing larger clutches or by increasing the
hatching success and survival rate of eggs and chicks. Most wader species tend to produce clutches
with the same amount of eggs (Beintema et al. 1995). Therefore, the second strategy seems to be
adopted by smaller wader bird species. In order to increase their reproduction rate, these species tend
to protect their nests by hiding them (Beintema 1983). This decreases the chance of nests to get
predated, but at the same time increases the negative effect of agricultural practices, since farmers will
not be able to spot and protect well-hidden nests (Beintema 1983).
16
Next to the nesting strategy, Beintema 1983 indicated that the timing of reproduction also
plays an important role. Nest hiding is only possible if sufficient vegetation is available. This
vegetation needs time to develop and forces smaller birds to nest relatively late in spring. Since
farming practices also start later in spring, the reproductive period of smaller species and the start of
agricultural activity are likely to coincide, thereby decreasing the reproduction success of these
meadow bird species. Early nesting species have a chance of raising chicks before farming practices
start and therefore will be affected by these practices less intensively (Beintema 1983). The effect of
the loss of a nest depend on the ability of a meadow bird species to produce a replacement clutch.
Northern Lapwing is, for example, a species that is known to be able to produce several replacement
clutches per year (Beintema 1983).
Based on the factors mentioned above, Beintema et al. 1995 created a vulnerability ranking.
This ranking is shown in figure 4. The disturbance ranges of five meadow bird species, Eurasian
Oystercatcher, Black-tailed Godwit, Northern Lapwing, Ruff and Common Redshank, are shown. The
x-axis is arbitrary and is based on the effects of agriculture on the reproductive success, as mentioned
earlier. Beintema 1983 also used figure 4 to explain the current distribution of meadow bird species in
the Netherlands. Beintema 1983 stated that, in order to produce eggs, female birds need a certain
amount of food. As said earlier, most waders produce equal clutch sizes and the amount of food
needed to produce a clutch is therefore species-specific. Bigger wader bird species produce bigger
eggs and therefore have a higher food demand in the form of earth-worms. Beintema et al. 1995 stated
that higher fertilization levels increase the amount of earth-worms. Bigger meadow bird species can
therefore only persist in high densities at higher fertilization levels. If the x-axis of figure 4 is seen as a
time scale (arbitrary), Beintema et al. 1995 stated that this is visible. Because of the intensification of
agriculture through time, the fertilization level will have been rising and with it the availability of
food. The heavier meadow bird species will then have reached high population numbers relatively
recent, whilst the disturbance ranges of the smaller species were already exceeded by that time and
populations of these species were therefore declining.
The increase of the Dutch Black-tailed Godwit population during the 1940’s and 1950’s,
followed by a decline that started during the 1970’s and the increase of the Dutch Eurasian
Oystercatcher (Haematopus ostralegus) during the 1950’s and 1960’s, followed by a more recent
decline, seems to prove the idea of Beintema et al. 1995.
Figure 4: Preferences and tolerance levels of five meadow bird species (y-axis) for agricultural intensity levels
(arbitrary) (x-axis). Alternatively, the intensity scale can be seen as an arbitrary time scale. Source: Beintema 1983.
17
Current Dutch meadow bird populations are the result of changes in the past. The Dutch polder
landscape, with its high meadow bird population densities, is a recent phenomenon. Meadow birds
originally inhabited coastal areas, natural grasslands, natural steppes and wetlands and expanded
their range into agricultural grasslands when agriculture started to develop. Initially, agriculture was
extensive and had a positive effect on meadow bird population densities. In more recent times,
intensification, especially CAP-driven after World War II (1957), turned out to negatively influence
meadow bird populations. Since different meadow bird species can cope with different disturbance
levels, Beintema 1983 developed a model that can be used to explain current meadow bird distribution
patterns and population trends.
18
3
Meadow bird protection
regulation in the
Netherlands
http://www.twitchers-retreat.co.uk/bed-and-breakfast-snettisham/rspb-reserves/titchwell-marsh-nature-reserve/
19
3. Meadow bird protection regulation in the Netherlands
The recent shift of agriculture purely being a factor positively influencing meadow bird population
densities towards also showing negative effects, indicates that regulation in order to protect Dutch
meadow bird population became necessary. This chapter will focus on the regulation and will seek to
answer the question: What was the first regulation considering meadow bird protection and how did
regulation evolve through time? Both national scale and European scale regulation will be discussed
and the possible effects of future changes will be named. The focus of this chapter will mainly be on
governmental regulation aiming at the protection of Dutch meadow bird populations in agricultural
areas.
3.1 Towards national meadow bird protection regulation – The Relatienota
The Dutch polder landscape with its high meadow bird population densities was taken for granted for
a long time (Brouwer 2005). Until about half a century ago, most people did not realize the importance
of the Netherlands being a meadow bird country (Brouwer 2005). This realization only became
general after meadow bird populations appeared to shrink. Up to that moment meadow bird protection
was only done on a voluntary basis, for example in the province of Friesland (Landschapsbeheer
Nederland). In this province, there has been a tradition of searching for Northern Lapwing eggs in
order to be the first to find one. This tradition cannot be seen separately from the protection of
Northern Lapwing nests, since the Frisian people realize that, in order to keep the tradition going, the
protection of the Northern Lapwing population is important. Also, individual farmers have been
adapting their farming practices in an effort to protect meadow bird populations on their land before
regulation considering meadow bird protection was developed. (Beintema et al. 1995)
During the 1970’s, meadow bird protection earned a more important status. This period can be
seen as a black period for meadow birds and in order to change this, the so called Dutch ‘Relatienota’
was introduces in 1975 (Breeuwer et al. 2009; Sanders et al. 2004; Verhulst 2007). According to the
Relatienota, farmers are not just responsible for producing agricultural products, they also influence
landscape and nature and should financially benefit from this. The idea was to compensate farmers for
financial losses arising though the extensification of farming practices in order to protect the landscape
and its biodiversity (Beintema 1991; Sanders et al. 2004; Teunissen et al. 20072; Teunissen et al. 2010;
Verhulst 2007). Farming practices determined the financial compensation. More extensive farming
resulted in higher financial compensation.
The aim of the Relatienota was to set up a ‘Relatienotagebied’, an area in which protection
measures, aiming at the protection of, among others, meadow birds, were taken (Beintema et al. 1995;
Sanders et al. 2004). The Relatienota included both meadow bird agreements and botanical agreements
(Kleijn et al. 20032). Initially, 200.000 ha should have been making up this Relatienotagebied, but this
turned out to be unachievable and this goal was therefore split up. First of all, an area of half the size
had to be realized. (Beintema et al. 1995)
Before realizing the Relatienotagebied, Dutch meadow bird land had to be assessed, in order
to determine which areas were most suitable meadow bird areas and which were not. This was done
using a pointing system. Different meadow bird species got a different value, depending on the state of
the population. Critical meadow bird species had a higher value than vulnerable meadow bird species,
vulnerable meadow bird species had a higher value than common meadow bird species, etc. In this
way, it was possible to score areas per hectare. Furthermore, indicator species could be used. These
species say something about the state of an area and the species that will most likely be present. An
example of an indicator species is Ruff. The presence of Ruff goes hand in hand with the presence of
more common species. Black-tailed Godwit can also be used as an indicator for the presence of other
meadow bird species. (Beintema et al. 1983)
Because of the time it took to assess meadow bird areas, it lasted until 1981 before the so
called agri-environment schemes were signed with farmers (Kleijn et al. 20032; Verhulst 2007). At the
same time, land was being bought for the creation of reserves. Reserves had been created since 1909,
20
when Natuurmonumenten started buying grasslands on Texel. Agreements with farmers lasted for six
years and comprised a strictly defined area (Teunissen et al. 20072; Teunissen et al. 2010). Also, these
agreements were set with individual farmers, on a voluntary basis. The high elongation rate (90%)
after the initial six years of the agreements showed the willingness of farmers to cooperate. (Beintema
et al. 1995)
During the 1980’s, the inventory on the effects of agri-environment schemes started. It became
clear that the nine different agreement types being used back then did not all have a positive effect on
meadow bird populations. The agreements could be split into relatively simple agreements, containing
a low amount of easily implementable measures, and more advanced agreements, containing more and
more extreme measures. Simple agri-environment schemes turned out to be ineffective. By increasing
the financial benefits for more advanced agreements and by revising the agreements applied at that
time, the government tried to optimize meadow bird protection in agricultural areas. The amount of
land under agri-environment schemes became substantial during the early 1990’s, when about 20.000
ha were present (Breeuwer et al. 2009; Sanders et al. 2004). During that decade, this amount grew to
roughly 68.000 ha of land (Sanders et al. 2004). (Beintema et al. 1995)
3.2 Towards European meadow bird protection regulation – Regulation 2078/92
The implementation of the Relatienota in 1975 was a relatively early measure to protect meadow bird
populations. The European Union, for example, first addressed the impact of agricultural
intensification on biodiversity only in 1985 (Green Paper) (CEC 1985). In that same year, EEC
Regulation 797/85 allowed member states to financially support biodiversity-rich or sensitive areas
(Kleijn et al. 20032). It took until 1992 before Regulation 2078/92 was introduced, requiring member
states to implement agri-environment schemes (EC 1997; Kleijn et al. 2003; Kleijn et al. 20032;
Verhulst 2007). Something that, thus, was implemented earlier in the Netherlands. Dutch agrienvironment schemes were mainly based on meadow bird protection, but this was no obligation
(Kleijn et al. 2004). Every country developed its own agri-environment schemes, with diverse goals
(Kleijn et al. 20032). During the last part of the last decade, about 25% of the European farmland area
was under some kind of an agri-environment scheme (EU 2005). Since after the implementation of
Regulation 2078/92 50-75% of the costs of implementing agri-environment schemes were funded by
the EU, member states thought of agri-environment schemes as a relatively cheap way of nature
conservation (Donald et al. 2006). This is illustrated by the fact that during the first ten years after the
implementation of Regulation 2078/92, 24 billion euro’s were spent on agri-environment schemes,
consistent with roughly 4% of the total EU expenditure on the CAP (EEA 2002). This was expected to
rise to about 10% of the expenditure (EC 1997).
3.3 Towards collective meadow bird protection – Programma Beheer
In the Netherland, so called ‘agri-environment cooperatives’ started to developed during the 1990’s
(Landschapsbeheer Nederland; Verhulst 2007). These are groups of neighboring farms that, by
working together, aimed for a better coordinated and more effective meadow bird protection. Since the
Relatienota did only allow for agri-environment schemes to be closed with individual farmers, there
was a need for change. The strict definition of the area that should be managed under an agrienvironment scheme was therefore let go of, to make cooperation between individual farmers possible.
In 2000, the so called ‘Programma beheer’ was introduced (Verhulst 2007). Programma beheer aimed
at improving meadow bird protection and consisted of two incentives: SN (Subsidieregeling
Natuurbeheer i.e. subsidies for nature conservation) and SAN (Subsidieregeling Agrarisch
Natuurbeheer i.e. subsidies for agricultural nature conservation) (Verhulst 2007). The latter, SAN,
concerned meadow bird protection, since most populations in the Netherlands can be found on
agricultural land. SAN offered four different meadow bird protection packages. Contrary to the
Relatienota, Programma beheer thus had packages that aimed specifically at the protection of meadow
bird populations. These packages had different demands when it came to an area, based on the amount
21
of meadow bird species present in the area and the amount of meadow bird species termed critical.
The packages were termed common meadow bird area, special common meadow bird area, species
rich meadow bird area and very species rich meadow bird area. All of them had a set of minimum
protection measures and their own financial compensation level. Agri-environment cooperatives were
able to sign cooperative agri-environment agreements (Verhulst 2007). Again, the state of the meadow
bird populations present in the area determined what package could be applied for. Furthermore,
cooperatives should be at least 100 ha in order to be eligible for a management contract (Verhulst
2007). Because all meadow bird protection packages had a set of minimum protection measures that
was very limited, Programma beheer gave farmers and agri-environment cooperatives a lot of freedom
to think of other, voluntary protection measures. Like the agri-environment schemes described before,
the agri-environment schemes under Programma beheer ran for six year. (Teunissen et al. 20072;
Teunissen et al. 2010; Van ‘t Veer et al. 2007)
3.4 Towards current regulation – SNL
In 2007, the SAN was reformed. From that moment on it was termed PSAN, since provinces became
responsible for the implementation. Before 2007 this happened on a national scale (Teunissen et al.
20072). Shortly after this reform, in 2010, Programma beheer was replaced by ‘Subsidiestelsel Natuuren Landschapsbeheer’ (SNL) (Van Doorn et al. 2012). Again, the 12 Dutch provinces play an
important role. Each province determines in which areas agricultural management and landscape
management are desirable and which management practices should be subsidized. In this way, a
province can be split into different regions, based on the desirable management level (ILG-regions i.e.
Investeringsbudget Landelijk Gebied). All of these ILG-regions are put into a nature management
plan, a national map containing all ILG-regions. (Teunissen et al. 2010)
The incentives present under Programma beheer (SN and SAN/PSAN) were replaced with the
introduction of SNL (2010) (Landschapsbeheer Nederland). SNL contains the Index Nature and
Landscape, comprising three parts: index nature management types, index agricultural nature
management types and index landscape management types. Meadow bird protection falls under the
second type, which aims, among others, at creating suitable meadow bird habitat, creating a resting
period and creating land suitable for chick survival. More information on the protection measures will
follow later on. Provinces can register certain ILG-regions as being regions in which only cooperative
management can take place. In the case of meadow birds, this means that agri-environment
cooperatives play an important role in these areas. Collective management is, however, not restricted
to these areas. (Teunissen et al. 2010)
3.5 Future regulation – CAP greening and the Natuurakkoord
Future Dutch meadow bird protection is uncertain, because changes in the present regulation are on
their way, both on the national (SNL) and the European scale (CAP). Since national scale regulation is
linked to the European CAP, the effect of changes on the national level can only be estimated based on
changes in the CAP. At this moment, about 90% of the agricultural land that is under some kind of
SNL subsidy is located outside the so called Dutch ‘Ecologische Hoofdstuctuur’ EHS (i.e. national
ecological network), which is a national-scale network of interlinked nature reserves that is only partly
realized. 75% of the management on this land aims at the protection of meadow bird populations of
which about 50% is situated outside the EHS. Nowadays, provinces are responsible for the protection
of these areas, but the ‘Natuurakkoord’ (Bestuursakkoord Decentralisatie Natuur i.e. nature
agreement), an agreement between the national government and the 12 provinces in 2010, is expected
to change this in the near future. Provinces will then be responsible for nature protection within the
EHS, whereas the national government will be responsible for nature protection outside the EHS. (Van
Doorn et al. 2012; Vogelbescherming 20122)
The CAP will be reformed in 2014, with the goal of making European subsidies ‘greener’.
One measure that most likely will be taken is subsidizing Ecological Focus Areas (EFA’s). The idea is
22
to use 7% of, for example arable land, for ecological purposes. In this way, the national government
might be able to get EU co-financing for nature conservation outside the EHS. The Natuurakkoord
states that this co-funding will arise from pillar 1 from the CAP. This pillar does not allow cooperative
management, something that is currently seen as important for the protection of meadow bird
populations. The other pillar, pillar 2, does allow cooperation and therefore seems more appropriate.
Nevertheless, the Dutch government is willing to just use finances derived from pillar 1. (Van Doorn
et al. 2012; Vogelbescherming 20122)
By using 7% of productive land in an ecological way, more non-productive farmland will
arise, which will positively influence biodiversity. Because the reform of the CAP will only take place
in 2014, it is unclear what will eventually be the EU’s demands when it comes to EFA’s. For meadow
bird protection it will be important to know if EFA’s may consist of (agricultural) grasslands and if
management practices will be allowed until a certain degree. Also, it seems like financing will be
aiming for the creation of more non-productive land. For meadow bird protection a certain degree of
management is necessary and it therefore is important to know if this is taken into account. (Van
Doorn et al. 2012; Vogelbescherming 20122)
For meadow bird populations within the initially planned EHS, changes in regulation will also
have effects. First of all, according to the Natuurakkoord, the area that was designated for nature
development within the EHS will become smaller. Because of this, meadow bird populations might
shift from inside the initially planned EHS to outside the revised EHS. The protection of nature within
the EHS will be funded by the national government, through a fund. Of course, the ability to protect
meadow bird populations will depend on the amount of money deposited in this fund. (Van Doorn et
al. 2012; Vogelbescherming 20122)
b
Meadow bird protection in the Netherlands started on a voluntary basis, with individual nest
protection and the alteration of farming practices. It took until 1975 (Relatienota) before the first
regulation considering meadow bird protection was introduced in the Netherlands. This was relatively
early, since the EU did only develop regulation in 1992 (Regulation 2078/92). Ever since the
introduction of regulation, there has been change. In the near future, Dutch meadow bird protection is
expected to be altered again, due to the Natuurakkoord and changes in the CAP. It is, however, not
clear what the effects will be, since the renewed CAP will only be implemented in 2014 and is
currently under debate.
23
4
Threats
http://www.aviflevoland.nl/html/Scholekster.html
24
4. Threats
The threats concerning meadow bird populations are multiple. Because nothing can be said about
protection measures before the threats have been discussed, this chapter will focus on these threats, in
order to give an idea on the complexity of the problem. What are the problems concerning meadow
bird populations? Because significant parts of the Dutch meadow bird populations are restricted to
agricultural land, this chapter will mainly focus on threats within agricultural land. However, overlap
exists between threats within agricultural areas and threats within reserves. This causes several
threats to apply to both agricultural areas and reserves. A general overview will be given at the end of
the chapter.
4.1 Habitat loss, fragmentation and disturbance
Since Dutch meadow bird populations are mostly restricted to agricultural land (e.g. 80% of the Dutch
Black-tailed Godwit population), speaking of habitat loss, in this case, mainly concerns the loss of
suitable agricultural grasslands (Beintema 19912; Beintema et al. 1995; Hagemeijer et al. 2004; Kleijn
et al. 2007; Swagemakers et al. 2009; Terwan et al. 2002). Important causes of this loss are
urbanization, infrastructural expansion, the development of ‘green areas’ and the transition of
agricultural grasslands into unsuitable croplands (e.g. Zea mays L.) (Sanders et al. 2004; Terwan et al.
2002). Besides this, the quality of the available agricultural land might also be a cause of habitat loss.
Changes in farming practices can alter the suitability of agricultural grasslands. These changes, mostly
indicated as agricultural intensification, are multiple, and will be described individually later on in this
chapter.
The problem of habitat loss is very straight forward. Every bird needs, among others, a certain
amount of food to survive. In the case of, for example, an adult Black-tailed Godwit, this food will
largely consist of earth-worms (Beintema et al. 1995; Terwan et al. 2002). In order to be able to
consume the minimum amount of earth-worms needed to survive, the bird needs a foraging area. The
amount of foraging area needed depends on the availability of earth-worms. According to
Compendium voor de Leefomgeving 2009, the amount of Dutch agricultural land, and thereby the
available foraging area, has been declining since the 1950’s. In 1980, about 2.600.000 ha of land were
termed agricultural land, whereas in 2006 this area shrunk to 2.200.000 ha. The shrinkage was caused
by urbanization, the expansion of the land area covered with forest and, to a lesser amount, by the
development of new nature (Compendium voor de Leefomgeving 2009). Because not all agricultural
land is suitable meadow bird land, the area of agricultural land consisting of grassland is an important
indicator for habitat loss. According to Compendium voor de Leefomgeving 2012, this area has been
shrinking since the 1980’s. In 2011, 53% of the Dutch agricultural land existed of grassland, thereby
making up the majority of the agricultural land (Compendium voor de Leefomgeving 2012).
Compendium voor de Leefomgeving 2012, however, distinguished between permanent grasslands,
temporary grasslands and natural grasslands and showed that the area covered with permanent
grassland declined by one third between 1980 and 2011. At the same time, the area covered with
temporary grassland showed a fivefold increase (Compendium voor de Leefomgeving 2012). As the
name states, temporary grasslands are grasslands that will be converted into different types of
agricultural production through time, an example of this being the conversion towards the cultivation
of Zea mays L. mentioned before. Terwan et al. 2002 stated that the area of agricultural grassland
declined by 21% between 1975-2000 and by 8% between 1990-2000. The shrinkage of both the total
area of Dutch agricultural land and the area of agricultural grassland forces the Black-tailed Godwit to
shift its foraging area or to disappear. Since there only is a limited amount of foraging area, habitat
loss will increase food competition and thereby decrease the carrying capacity of the Netherlands
being a meadow bird country.
Since my personal impression concerning habitat loss is that there is general consensus on the
importance of this factor, but a clear argumentation or calculation to justify this view is lacking, a
calculation is needed to test for the importance of habitat loss. In the case of Black-tailed Godwit, the
25
Netherlands annually contain roughly 40.000 breeding pairs (Vogelbescherming 20123). According to
Guldemond et al. 2009, a breeding density of 20 breeding pairs per 100 ha is required for a stable
Dutch Black-tailed Godwit population under mosaic management. This corresponds to 5 ha of
agricultural grassland per breeding pair. Compendium voor de Leefomgeving 2012 stated that, in
2011, 766.000 ha of Dutch agricultural land were permanent grassland. If we take the standard of 1.4
ha of chick land per breeding pair by Teunissen et al. 2007 as a standard, one breeding pair needs 6.4
ha of agricultural grassland. This corresponds to 256.000 ha of agricultural grassland for the total
Dutch breeding population. This number might be an underestimation of the actual situation, because
breeding birds might need additional foraging area. However, the actual area covered with permanent
grassland far exceeds the demand and correcting for this will therefore not result in a different view.
The calculation shows that the general consensus on the importance of habitat loss is unjustified.
If the quality of suitable meadow bird areas is observed instead of the quantity, the process of
habitat degradation becomes clear. Since farming practices partly determine the suitability of an area
as meadow bird land and because these practices will be described later on in this chapter, this
paragraph will further focus on aspects besides farming practices. In the case of meadow bird habitat
degradation, an important factor is habitat fragmentation. According to Johnson 2001, habitat
fragmentation causes habitat degradation in three different ways: by patch size effects, edge effects
and isolation effects. In the example of the Black-tailed Godwit, the presence of a highway is a form
of habitat fragmentation. Since the Black-tailed Godwit is capable of crossing infrastructure, edge
effects are the main threat concerning meadow bird populations when it comes to habitat
fragmentation. Reijnen et al. 1991 demonstrated the negative edge effects concerned with the presence
of a highway, shown in table 2. Black-tailed Godwit proves to be relatively sensitive when it comes to
traffic and the presence of a highway. Black-tailed Godwit population densities are negatively affected
by the presence of a highway over more than a kilometer away, whereas Eurasian Coot (Fulica atra)
densities prove to be affected by the presence of a highway only within 100 meters away. Sanders et
al. 2004 stated that the effect of traffic on adult meadow bird mortality is negligible. The lower bird
population densities within the area of effect of a highway are caused by birds avoiding these areas.
Hille Ris Lambers et al. 2008 stated that traffic noise has the biggest area of effect. Visual disturbance
by cars and illumination have smaller areas of effect and are therefore assumed to only affect bird
densities within the area of effect of traffic noise (Hille Ris Lambers et al. 2008). Reijnen et al. 1997
stated that, in 1986, traffic was responsible for 16% of the decline in Black-tailed Godwit breeding
populations. Furthermore, Reijnen et al. 1997 expected this number to rise towards 30% by 2010. The
effect of habitat fragmentation might explain the general consensus on the importance of habitat loss,
because the value of 20 breeding pairs per 100 ha, used in the calculation shown above, is a standard
required for stable Dutch Black-tailed Godwit populations (Guldemond et al. 2009). Habitat
fragmentation might cause current breeding densities to not meet these 20 breeding pairs per ha,
thereby causing the demand for breeding grounds to be higher than calculated. Habitat loss and habitat
fragmentation, thus, jointly influence the availability of suitable meadow bird land and can therefore
be considered direct habitat loss (habitat loss) and indirect habitat loss (habitat fragmentation i.e. edge
effects).
The negative edge effects caused by the presence of a highway can make that the presence of a
highway can be considered a disturbance factor. Some other examples are: agricultural practices,
visual disturbance by tourists and protection measures (Brouwer 2005; Sanders et al. 2004). Individual
nest protection is an example of a protection measure that can be seen as a form of disturbance, since
nests need to be searched before protection can take place (Brouwer 2005).
26
Table 2: The area of effect of the presence of a highway for seven meadow bird species. Source: Reijnen et al. 1991.
Species
Black-tailed Godwit
Northern Lapwing
Eurasian Skylark
Northern Shoveler
Mallard
Meadow Pipit
Eurasian Coot
Area of effect
> 1000 m
700 m
600 m
400 m
300 m
120 m
100 m
4.2 Grazing and mowing
The threats concerning grazing and mowing are the risks of nest destruction and chick mortality
(Brouwer 2005; Sanders et al. 2004). In the case of grazing, the density and period of livestock grazing
are important aspects, as a higher livestock density increases the risk of a nest or chick being trampled
and since the presence of nests and chicks is restricted to the reproductive period of meadow birds
(Brouwer 2005). Brouwer 2005 stated that in the period between April 1st and June 15th, intensive
grazing should be prevented. Furthermore, the risk of nest trampling depends on the bird species
involved. Northern lapwings are known to be ‘nest defenders’ that will try to keep cattle away from
their eggs and even protect their eggs against cattle (Beintema et al. 1995). On the other hand, Blacktailed Godwit and Common Redshank are more of a type that can be named ‘hiders’ (Beintema et al.
1995). By sitting still and hiding, these species try to keep cattle away. The preference of Common
Redshanks to nest near Northern Lapwings makes them benefit from the nest defending ability of
Northern Lapwings (Beintema et al. 1995).
In order to get an idea on the extent of grazing as a threat to Dutch meadow bird populations,
the above mentioned aspects need to be discussed in more detail. When it comes to the period of
livestock grazing, about a century ago, it was the weather that determined the accessibility of a field
(Beintema et al. 1995). Improved drainage techniques now allow access earlier in the year and by
enhanced fertilization the vegetation growth was promoted (Kleijn et al. 2007; Kleijn et al. 2009;
Sanders et al. 2004; Verhulst et al. 2011). Due to the earlier field access, meadow birds might
nowadays lack a disturbance-free reproductive period (Kleijn et al. 2007). As shown in table 3,
different meadow bird species can tolerate different cattle grazing densities. Northern Lapwing can
cope with relatively high cattle densities, which has to do with this species being a nest defender, as
mentioned earlier. It seems likely that more tolerant species will be less affected by advanced grazing
dates. Besides shifts in the grazing period, stocks of cattle have been changing. According to
Compendium voor de Leefomgeving 20124, the Netherlands housed 3.9 million cows in 2009,
compared to 5.2 million cows in 1980. Furthermore, van der Schans et al. 2006 showed that the
percentage of dairy cows kept inside all year round has been growing since the 1980’s. This
percentage grew from roughly 2% in 1980 towards roughly 13% in 2006 (van der Schans et al. 2006).
The problem of cattle grazing, thus, seems to be a threat that has been declining in strength through
time. According to van der Schans et al. 2006, the percentage of dairy cows that will be kept inside all
year round can be expected to grow towards 17-28% in 2016, thereby further limiting the negative
effects grazing has on Dutch meadow bird populations.
In the case of mowing, the risks of nest destruction and chick mortality also depend on timing
(Brouwer 2005). Since the presence of eggs and chicks is restricted to a certain period (April 1st-June
15th), mowing will have negative effects when it coincides with the reproductive period of meadow
birds (Brouwer 2005). This reproductive period is species specific and therefore mowing practices will
affect different meadow bird species in a different degree. Table 3 gives an idea on the tolerance of the
four focus species when it comes to the first mowing practices of the year. It becomes clear that
Northern Lapwing tolerates relatively early mowing practices. This corresponds with the relatively
early start of the reproductive season of the Northern Lapwing (Beintema et al. 1995).
27
Table 3: The tolerated first mowing dates and cattle densities for the four focus species. Source: Sanders et al. 2004.
Bird species
Northern Lapwing
Black-tailed Godwit
Common Redshank
Eurasian Oystercatcher
Tolerance
first mowing date
May 5th
May 30th
June 5th
> June 15th
Tolerance
cattle density (per ha)
5
2
1
3
The earlier field access described above did not only allow earlier grazing, it also made it possible for
mowing practices to shift in time (Kleijn et al. 2007; Kleijn et al. 2009; Verhulst et al. 2011).
Nowadays, the first mowing practices can take place during the middle of May, whereas this was
historically delayed towards the last part of May or the first part of June (Kleijn et al. 2007; Sanders et
al. 2004). Contrary to grazing, mowing practices have not shown signs of extensification. Instead,
mowing practices nowadays take place at a higher speed, at a larger scale and the strips in which fields
were mown traditionally have broadened (Sanders et al. 2004). Mowing is furthermore outsourced
more often (Kleijn et al. 2007). Terwan et al. 2002 stated that, between 1990-2002, the mowing
efficiency increased from 1.6 ha/h towards 1.8 ha/h. It therefore seems like mowing is a threat that is
still increasing in severity.
Next to the risks of nest trampling and chick mortality, livestock grazing can have benefits for
meadow birds. One of these benefits is manure production during grazing. Manure attracts insects, the
main food source for meadow bird chicks. Furthermore, it can be seen as a form of fertilization, which
will be discussed next. Moreover, grazing and mowing alter the vegetation structure. The importance
of the vegetation structure will be described later on (Sanders et al. 2004).
4.3 Manuring
When speaking of fertilization, artificial and organic fertilizers need to be distinguished. According to
Compendium voor de Leefomgeving 2011, the Dutch agricultural sector currently produces relatively
low amounts of N and P in manure, compared to the levels produced between 1970-1986. During this
period, N and P surpluses in manure increased due to the establishment and growth of intensive cattle
farming that demanded the import of concentrated feeds (Compendium voor de Leefomgeving 2011).
Furthermore, to fulfill the demand for fodder, the application of artificial N fertilizers increased
(Compendium voor de Leefomgeving 2011). A decrease in the amount of P in concentrated feeds after
1975 caused P surpluses to increase more gradual between 1975-1986 (Compendium voor de
Leefomgeving 2011). The rise in the N and P production in manure between 1975-1986 caused the
application of N and P to rise (Compendium voor de Leefomgeving 20125). With the implementation
of regulation (e.g. ‘Beschikking Superheffing’ 1984 and ‘Mestwetgeving’ 1987), the aim was to lower
the production and utilization of N and P (Compendium voor de Leefomgeving 20125). As a
consequence, the production of both N and P in manure declined with respectively 37% and 47%
between 1986-2011 (Compendium voor de Leefomgeving 20125). These declines correspond to
declines in manure production surpluses of respectively 55% and 73% (Compendium voor de
Leefomgeving 20125). Due to this decline, the current production of N and P is back at the 1970 level
(Compendium voor de Leefomgeving 20122). A major contributor to the decline is the reduction of
cattle manure production (Compendium voor de Leefomgeving 20122). This production declined by
one fourth, which was a large reduction, knowing that cattle was responsible for 75% of the total
manure production (Compendium voor de Leefomgeving 20122). Furthermore, the utilization of
artificial fertilizers declined. Artificial N fertilizer application decreased rapidly from the 1980’s on
(Compendium voor de Leefomgeving 20092). Artificial K and P fertilizer application decreased more
gradually from the 1950’s on (Compendium voor de Leefomgeving 20092).
Currently, the Dutch government regulates the maximum application of fertilizers by setting
standards (Rijksoverheid 2012). These standards are based on the European Nitrate Directive (1991)
(Rijksoverheid 2012). In the case of meadow birds, the application of artificial and organic fertilizers
28
will affect the presence of food, which will be described later on in this paragraph, and the vegetation
structure, which will be discussed later on in this chapter. The direct effect of manuring is comparable
to that of mowing. This, however, only applies for the manure injection techniques. By injecting
manure directly into the soil, the survival chance of nests present is about zero (Brouwer 2005).
Applying fertilizer by depositing it on the surface, instead of injecting it, also causes nest loss, but the
survival change is considerably higher, about 85% (Brouwer 2005).
The process of manure application, thus, has a direct negative effect on meadow bird
populations. It is, however, impossible to stop using fertilizers in agricultural areas, the areas where
most meadow bird species are partly restricted to (Beintema 19912; Beintema et al. 1995; Hagemeijer
et al. 2004; Kleijn et al. 2007; Swagemakers et al. 2009; Terwan et al. 2002). In meadow bird reserves,
this opportunity does exists. It has been shown that by stopping the application of fertilizers in some
reserves, attenuation starts, the Ph of the soil declines and the vegetation shifts towards a Juncusdominated (Rush) vegetation type (Sanders et al. 2004). These changes do not benefit meadow bird
populations. The termination of fertilization in these areas and the accompanied decline in Ph mainly
are important factors, since they negatively affect the presence of earth-worms, the main food source
of adult wader species (Beintema et al. 1995; Sanders et al. 2004; Terwan et al. 2002).
When speaking of fertilization, there thus are different fertilizer types (i.e. artificial fertilizers
and organic fertilizers), as described above. Oosterveld 2006 investigated the effect of three different
manuring types: the injection of liquid manure (‘zodebemesting’), the deposition of liquid manure
(‘sleepvoet’) and the deposition of solid manure (‘vaste mest’). During 2002-2005, the effect of these
different types on earth-worm densities had been tested.
Figure 5 shows the long-term effect of all three manuring types on the number of earth-worms.
These earth-worm numbers are mean earth-worm numbers that resulted from five surveys (MarchJune), three years after the start of the experiment (2005). Significant differences in the earth-worm
counts between the manuring types ‘sleepvoet’ and ‘vaste mest’ and between the manuring types
‘zodebemesting’ and ‘vaste mest’ exist. The manuring type ‘vaste mest’ therefore seems most
beneficial for the food availability of adult waders. However, Oosterveld 2006 also mentioned that,
looking at the total weight of the earth-worms present under different manuring types, no significant
differences were found. Therefore, ‘vaste mest’ resulted in more, but lighter earth-worms, whereas the
other manuring types resulted in less, but heavier earth-worms. (Oosterveld 2006)
By observing the foraging behavior of adult Black-tailed Godwits, Oosterveld 2006 concluded
that different manuring types did not affect this behavior. No preference for foraging areas under one
of the manuring types was found and it therefore seems likely that either the relatively low numbers of
earth-worms under two of the manuring types were buffered by an increase in the mean body mass of
the earth-worms or that the relatively low numbers of earth-worms under two of the manuring types
were still high enough to not cause birds to prefer certain foraging areas above others. (Oosterveld
2006)
29
Figure 5: The effect of three different manuring types (x-axis) on the amount of earth-worms (per m2) present in the
soil (y-axis). Source: Oosterveld 2006.
4.4 Desiccation
As stated in the previous paragraphs, drainage nowadays allows relatively early access to agricultural
land (Sanders et al. 2004; Verhulst et al. 2011). Furthermore, the production of crops benefits from
artificially lowered water table levels. In the case of agricultural land, water management changed
through time by the lowering of water table levels, the canalization of ditches, streams and rivers and
the improvement of drainage techniques. This process started during the early 1970’s (Kleijn et al.
2009). Initially, no negative side effects of these changes were recognized. This changed during the
last part of the 1970’s and 1980’s, during which the problem of desiccation was first addressed.
Factors like water abstraction and the reclamation of land were partly responsible for desiccation, but
roughly 60% of it was related to agriculture, making agriculture the main cause. At first, desiccation
will merely cause hydrological changes, subsequently followed by the disappearance of characteristic
plant species. To counteract the negative effects on nature, the Dutch government defined that the area
of desiccated land should have decreased by 25% in 2000, compared to the situation in 1985. The aim
of a 40% decline was set for 2010. (van Vliet et al. 2002)
Even though evaluation reports on the current state of desiccated land show that the results
lack behind, attention on the problem since the 1970’s shows that the intensification of drainage had
stopped, i.e. the horizontal position of the water table level with respect to the mowing field had
stopped lowering (van Vliet et al. 2002). The problem with drainage concerns both the availability of
food and the vegetation composition. Since the vegetation composition will be described as a separate
threat in the next paragraph, this paragraph will now focus on the effect desiccation has on the
availability of food. Before doing this, it is important to realize that the effect of drainage on meadow
bird species is species-specific. Roughly, two groups of meadow birds can be described, based on their
sensitivity to drainage: the Ruff-group and the Black-tailed Godwit-group (Oosterveld 2006). The
30
Ruff-group is more sensitive to lower water table levels and can tolerate fluctuations between 0 and 20
cm below the mowing field (Oosterveld 2006). The Black-tailed Godwit-group is less sensitive and
can tolerate fluctuations between 0 and 80 cm below the mowing field (Oosterveld 2006). Black-tailed
Godwit, Common Redshank, Eurasian Oystercatcher and Northern Lapwing, the four focus species,
belong to the Black-tailed Godwit-group (Oosterveld 2006).
Speaking of the effect of desiccation on the availability of food, it concern the availability of
earth-worms. Earth-worm densities seem to be the main reason for the ability of meadow bird species
to cope with drainage (Oosterveld 2006). First of all, earth-worm densities are positively influenced by
soil moisture. A higher water table level therefore means more earth-worms, but also a better
accessibility of these earth-worm (Brouwer 2005). Not only will earth-worms be present closer to the
soil surface, higher water table levels also make the soil more easily penetrable for meadow bird beaks
(Brouwer 2005; Sanders et al. 2005). A possible explanation for the relatively high tolerance of the
Black-tailed Godwit-group for drainage, might be that lower parts, like ditches or trenches, provide
sufficient foraging area on relatively wet soils like peat and clay (Oosterveld 2006).
Not only the water table level itself is important, fluctuations throughout the year also affect
meadow bird populations. Historically, spring conditions were wet compared to summer conditions
(Brouwer 2005). Because of the wet spring conditions, meadow birds arriving in the Netherlands
could collect plenty of food to recover from their journey. Nowadays, because farmers are able to start
farming practices earlier in the year, spring water table levels are relatively low compared to summer
water table levels and do thus no longer meet the requirements of meadow birds. Brouwer 2005 stated
that the accessibility of earth-worms in dry years is suspected to limit the amount of Black-tailed
Godwits reaching the condition needed to start reproducing.
4.5 Vegetation composition
The combination of grazing and mowing, fertilization and drainage, described above, has implications
for the local vegetation composition. This composition affects the foraging behavior of meadow birds.
Roughly, two groups of meadow birds can be defined, based on their food preferences: ‘vegetation
foragers’ and ‘soil foragers’ (Kleijn et al. 2007). As the names indicate, the vegetation foragers mainly
depend on vegetation-dwelling food, whereas soil foragers mainly rely on soil-dwelling food (Kleijn et
al. 2007). The example of an adult Black-tailed Godwit, used earlier, is an example of a soil forager,
since earth-worms form the main food source (Beintema et al. 1995; Terwan et al. 2002). The shape of
the beak of most wader species reveals that this holds for most of them. However, Northern Lapwing
seems to be more of a generalist that adapts to local food conditions (Kleijn et al. 2007). In contrast to
adult birds, chicks can have other food preferences. In the case of Black-tailed Godwit, chicks are
vegetation foragers (Beintema et al. 1991).
Differences in foraging behavior influence the preference for a certain vegetation composition.
One can imagine that soil foragers prefer a vegetation structure that allows optimal access to the soil,
which corresponds to a short and open structure (Atkinson et al. 2004; Devereux et al. 2004. 2004;
Buckingham et al. 2006). However, vegetation foragers need a vegetation composition that houses
considerable amounts of insects to be able to gather the minimum amount of insects needed to survive
(Buckingham et al. 2006). Since most literature concerning vegetation composition addresses Blacktailed Godwit chicks, the focus of this paragraph will do so (unless stated differently).
The vegetation composition seems to be most important for meadow bird chicks. This seems
obvious, since these extract insects directly from the vegetation, whereas adult birds do not and
perceive vegetation as a physical barrier between them and the soil (Kleijn et al. 2007). Verhulst et al.
2008 examined the effect of different aspects of the local vegetation on the availability of insects.
Because the diet of Black-tailed Godwit chicks changes through time, Verhulst et al. 2008 both looked
at the total availability of insects and the availability of large insects (> 4 mm). During the first week
after hatching, no preference for insects with a certain size exists, but after this, larger insects will
form the main food source. After three weeks, soil-dwelling animals become part of the diet, since the
beak starts to develop into its characteristic shape. However, vegetation-dwelling animals make up
most of a chick’s diet until reaching the age of being fully-fledged. Surveys were therefore performed
31
during the start of May (hatching period) and the middle of May (large insects form the main food
source). The results are shown in figure 6. During both survey periods, areas with a wide range of
management practices were included, in order to give a general idea on the development of (large)
insect numbers. (Verhulst et al. 2008)
Figure 6: The amount of insects (A) and large insects (> 4 mm; B) (y-axis) present during both survey periods (x-axis).
Different letters indicate significance. Based on: Verhulst et al. 2008.
When figure 6 is observed, figure 6a shows a clear rise in the total amount of insects present during
the start of May and the middle of May. Figure 6b, however, shows an opposite view, with the number
of large insects during the start of May exceeding the number of large insect during the middle of
May. To check for the possible effect of management, Verhulst et al. 2008 compared different
management types, shown in figure 7. In this figure, the term ‘grazed’ encompasses fields that had
been grazed on during the first part of May. ‘Mown’ fields had, at the first survey, been regenerating
for about two weeks. ‘Common long’ and ‘postponed mowing’ differed in the presence (postponed
mowing) or absence (common long) of agri-environment schemes.
Figure 7: The amount of insects present during early (A) and middle (B) May (y-axis) at differently managed fields (xaxis). Different letters indicate significance. Based on: Verhulst et al. 2008.
Figure 7a indicates that, at the start of May, mown fields harbor significantly lower amounts of insects
than the fields managed in one of the other three ways. This difference is not present during the middle
of May (figure 7b). Taking into account just large insects results in figure 8. Figure 8a clarifies that,
during the start of May, mown fields contain significantly lower insect numbers than the other field
types. Postponed mowing results in relatively high insect counts, whereas grazed and common long
fields harbor intermediate numbers of insects. For the middle of May, again, differences disappear
(figure 8b).
32
Figure 8: The amount of large insects (> 4 mm) present during early (A) and middle (B) May (y-axis) at differently
managed fields (x-axis). Different letters indicate significance. Based on: Verhulst et al. 2008.
Figure 7 seems to suggest that a positive correlation exists between vegetation length and insect count.
Verhulst et al. 2008, however, showed this pattern only partly. An optimum for vegetation length
seems to exist (20-40 cm), above which both the total number of insects and the amount of large
insects starts to decline.
Besides vegetation length, vegetation structure might also affect insect populations. Verhulst
et al. 2008 showed that during both survey periods, the total number of insects and the amount of large
insects increased with increasing vegetation structure i.e. variation in vegetation structure within a
field.
Like Verhulst et al. 2008, Kleijn et al. 2007 found the total amount of insects to increase
during the breeding season, whereas the amount of large insects declined. Kleijn et al. 2007, however,
took into account some additional factors that could have affected (large) insect counts. The first factor
taken into account was the plant species composition of a field. Kleijn et al. 2007 distinguished
between four different vegetation types, representing a gradient in management types. The extensive
part of the gradient existed of fields with postponed mowing practices and lacking or restricted
fertilizer application (‘herb-rich – restricted fertilization’, ‘herb-rich – poor’). The intensive part of the
gradient existed of fields with common management practices, either mown or unmown (‘common
long’, ‘mown’). Kleijn et al. 2007 showed that the herb-rich (higher species richness) vegetation types
housed both higher insect numbers and higher amounts of large insects. Furthermore, the vegetation
density was observed as a factor that could influence the foraging success of Black-tailed Godwit
chicks. Figure 9 indicates that both herb-rich vegetation types (‘herb-rich – restricted fertilization’ ,
‘herb-rich – poor’ о) show a relatively low growth rate. This is most likely caused by relatively low
fertilization levels in these fields. The lower growth rates cause the vegetation density to increase
relatively slowly, whereas the field with a common vegetation (‘common long’ , ‘mown’ ) will
become impenetrable relatively fast. The quality of an area does therefore depend on both the food
availability and the penetrability of a field. One can imagine that a hardly penetrable field will cause
chicks to spend a lot of energy on mobility, thereby increasing energy demands. Since hardly
penetrable field will also decrease the capturing success of prey, this combination causes relatively
dense vegetation to be unsuitable foraging area for chicks. A relatively high vegetation growth rate
will cause a field to be suitable chick foraging area for only a limited period, whereas relatively low
growth rates will cause a field to be suitable over a longer time span. (Kleijn et al. 2007)
Intensive agricultural practices cause the vegetation structure in agricultural areas to be
uniform (Kleijn et al. 2009; SOVON 2010). Fertilization and drainage cause the vegetation growth
rate to be high (figure 9) and therefore allow early grazing and mowing, a higher grazing density and
higher mowing frequencies (Kleijn et al. 2007). The amount of short grass, compared to historically
more extensive farming practices, increased both in time and space (Kleijn et al. 2007). Current
farming practices therefore cause the actual vegetation structure and the vegetation structure preferred
by meadow bird chicks to differ, thereby putting the food availability for meadow bird chicks under
pressure.
As mentioned, the combination of grazing and mowing, fertilization and drainage has
implications for the local vegetation composition. The examples described investigated the effects of
33
different management types and did not discriminate between the factors making up these
management types. Kleijn et al. 2009 did discriminate between these factors and investigated the
effect of fertilization and drainage on the vegetation composition. According to Kleijn et al. 2009,
fertilization and drainage affect the vegetation structure in a cooperative way. A natural, high water
table level in combination with fertilization proved to have a relatively small promoting effect on the
vegetation height and structure, since not the availability of nutrients, but the anoxic soil conditions
limit the vegetation development. An artificially lowered water table in absence of fertilization showed
the same result, since the availability of nutrients is the limited factor under this condition. On the
other hand, a combination of both an artificially lowered water table level and fertilization caused the
vegetation to become higher and denser. These results by Kleijn et al. 2009 indicate that by limiting
either fertilization or drainage, the development of vegetation will be slowed down.
Figure 9: Height development of different vegetation types (y-axis) after the 8th of May (y-axis). Common long,
mown, Herb-rich – fertilization, о Herb-rich – reduced fertilization. Source: Kleijn et al. 2007.
4.6 Predation
Predation affects the reproductive capacity of meadow bird species, since eggs and chicks are easy
targets. Beintema et al. 1995 stated that, because of the earlier access of farmers to their fields, caused
by increased drainage, predators like Red Fox (Vulpes vulpes) also gained earlier access. According to
this theory, predators might have adapted to the presence of meadow bird populations only recently,
resulting in increasing levels of clutch and chick predation. Nest surveys during 1996-2004 resulted in
figure 10. This figure shows the predation on clutches of all meadow bird species present within the
survey areas between 1996-2004. Voluntary nest protection took place within the survey areas.
When figure 10 is observed, there indeed seems to be a positive trend, with predation losses of
about 11% in 1996 rising to predation losses of about 17% in 2004. Two other voluntary nest surveys
took place during the last part of the 1980’s and the last part of the 1990’s and in 2000 and 2004.
34
These surveys did not only look at the chance of nest predation, but also took other factors of nest loss
into account. The result of these surveys are shown in figure 11 and figure 12.
Figure 10: Annual nest losses through predation (y-axis) during 1996-2004 (x-axis) for all meadow bird species
present within the survey areas. Voluntary nest protection took place throughout the survey period. Source:
Teunissen et al. 2005.
Figure 11 and figure 12 also show a rise in predation levels for both species. The figures clarify that
predation is not the only cause of nest loss that increased, since the daily nest loss caused by farming
practices also shows a significant increase (figure 11). Figure 12 will underestimate the effect of
farming practices on nest loss, since the data used in constructing the figure was gathered in areas
where nest protection took place. Without these protection measures, the losses through farming
practices would have been 30-50% higher (Teunissen et al. 2005).
Figure 11: Daily nest losses for Northern Lapwing (left) and Black-tailed Godwit (right) (y-axis) during the late 1980’s
and late 1990’s (x-axis). Losses are split into four categories, the causes of nest loss. Numbers near the bars indicate
significance and give the difference between both survey periods. No voluntary nest protection took place during the
survey periods. Source: Teunissen et al. 2005.
35
Figure 12: Annual nest losses for Northern Lapwing and Black-tailed Godwit during in 2000 and 2004. Losses are
split into different categories, the causes of nest loss. Voluntary nest protection took place during both 2000 and 2004.
Source: Teunissen et al. 2005.
When the predation losses shown in figure 10 are compared to these losses in figure 12, there are
differences in the nest predation levels within the same year. According to figure 12, nest predation
levels are higher than according to figure 10. A possible explanation for these differences might be
regional differences in nest predation pressures. The survey group in 2000 and 2004 therefore created
national maps, on which regional differences in nest predation pressures were defined. These maps are
shown in figure 13. Predation pressures are given as indexes. A predation index of 1 therefore
indicates a predation pressure that is equal to the mean national predation level.
Figure 13: Nest predation maps for 2000 (left) and 2004 (right). Predation pressures are given as indexes. An index of
1 corresponds to the mean national predation level. Missing data is presented in gray and white. The maps apply for
meadow birds in general. Source: Teunissen et al. 2005.
By comparing both maps, the increasing predation level on clutches of Black-tailed Godwits and
Northern Lapwings becomes visible. This is according to the figures shown above. When addressing
regional variation, it becomes clear that during 2004, no data was collected in the province Friesland.
Furthermore, local data gaps are visible, they lack a color. Both maps seem to roughly consist of two
36
parts. The northeastern and southeastern part of the country are characterized by relatively high nest
predation levels, whereas the western part of the country mostly lacks these relatively high levels of
nest predation. The border between these two regions shows a clear westward shift from 2000 to 2004.
It therefore seems like nest predation has been expanding from the eastern part of the Netherlands.
Nest predation, thus, seems to be the most important factor in determining the chance of
hatching, according to figure 12. Predators, however, do not only focus on eggs. Chick predation
might also negatively influence the reproduction process of meadow bird species. The effect of this
form of predation on the chance of chicks reaching the age of being fully-fledged was tested between
2003-2005 using radio transmitters. It turned out that only a limited percentage of chicks reaches this
age: 7% for Black-tailed Godwit, 14% for Northern Lapwing. Differences exist between regions, as
could have been expected based on figure 13, and between subsequent years, which can be explained
by factors like weather conditions. Predation accounts for 50-70% of the chick mortality reported
before reaching the age of being fully-fledged. The likelihood of a chick to get predated on showed a
relation to the age of the chick. In the first period after hatching, the highest losses were reported.
These numbers gradually declined, until about ten days after hatching a period of constant losses was
reported, after which the chance of survival, again, gradually increased. A survey of predation on
chicks over a longer period, as shown for nest predation in figure 10, is lacking. Still, it seems likely
that chick predation has increased like nest predation, for predators could predate on both nests and
chicks. (Teunissen et al. 2005)
Besides investigating the causes of chick mortality, Teunissen et al. 2005 determined the
predator species responsible for nest predation, using cameras equipped with heath sensors. Predation
took place both during the day and during the night, with birds dominating during the day and
mammals dominating during the night. Both forms were in balance up to a nest predation level of
about 50%, above which nightly predation became more dominant. Nest predation in areas with
relatively high nest losses therefore is dominated by nightly predation, whereas nest predation in areas
with lower nest losses shows no domination by one of both forms.
With the camera images, a total of 10 nest predator species could be identified. Four of them
were bird species: Carrion Crow (Corvus corone), Western Marsh-harrier (Circus aeruginosus),
Northern Goshawk (Accipiter gentilis) and Eurasian Oystercatcher (Haematopus ostralegus). The
remaining six species were mammals: Red Fox (Vulpes vulpes), Stoat (Mustela erminea), Beech
Marten (Martes foina), European Polecat (Mustela putorius), European Hedgehog (Erinaceus
europaeus) and Least Weasel (Mustela nivalis). In the case of chick predation, fifteen predators were
identified, eleven of them being bird species: Common Buzzard (Buteo buteo), Grey Heron (Ardea
cinerea), Carrion Crow (Corvus corone), Common Kestrel (Falco tinnunculus), Northern Goshawk
(Accipiter gentilis), Eurasian Sparrowhawk (Accipiter nisus), Western Marsh-harrier (Circus
aeruginosus), Western Jackdaw (Corvus monedula), Lesser Black-backed Gull (Larus fuscus),
Common Gull (Larus canus), White Stork (Ciconia ciconia) and four being mammals: Domestic Cat
(Felis catus), Red Fox (Vulpes vulpes), Rat (Rattus rattus/norvegicus) and Stoat (Mustela erminea).
Concerning nest predation, no clear pattern was observed in the importance of the different predators
on nest predation. The presence of Red Fox (Vulpes vulpes), however, correlated with high predation
levels. In the case of chick predation, bird species accounted for 2-4 times more kills than mammals
did. The most efficient chick predators were Common Buzzard (Buteo buteo), Grey Heron (Ardea
cinerea) and Stoat (Mustela erminea). Furthermore, chick predation differed between the two
observed meadow bird species. Northern Lapwing chicks were mostly predated by Grey Heron (Ardea
cinerea), whereas Black-tailed Godwit chicks were mostly predated by Common Buzzard (Buteo
buteo) and Stoat (Mustela erminea). Most likely, this was caused by the different habitat preferences
of Black-tailed Godwit and Northern Lapwing. Northern Lapwing prefers a shorter vegetation cover.
Teunissen et al. 2005 found the chance of chick predation to be highest in mown areas, followed by
areas where the vegetation was mown and vegetation was recovering (15-30 cm) and lowest in
unmown areas, which support the idea that habitat features play a role. Besides agricultural activity
(mowing), another important factor that can enhance predation is a decrease in the openness of the
landscape. Patches of forest, for example, provide suitable predator habitat and can be used as
lookouts for spotting meadow bird nests or chicks (Brouwer 2005). (Teunissen et al. 2005)
37
4.7 Overwintering
When considering the threats to meadow bird populations, it is important to realize that most species
are migratory birds. Threats in foreign countries therefore also play a role in determining population
trends, in this case through altering the survival of mature birds. The four focus species overwinter in
either the Netherlands, elsewhere in Western Europe or in Africa. Since threats will be locationspecific, this paragraph will briefly describe the threats that the four focus species have to cope with
outside the breeding season. These threats will not be discussed further on, because the focus of this
thesis is on national-scale threats and protection measures.
The Dutch Eurasian Oystercatcher breeding population is mostly restricted to the Netherlands
throughout the year. After the reproductive period, individuals will migrate towards the coast, where
they forage until the next breeding period starts. The main threat during the overwintering period is
starvation, caused by the past overexploitation of Cockles and the disappearance of mussel banks from
the intertidal zone of the Wadden Sea. Furthermore, the erosion of sandbanks situated in the
Oosterschelde causes the availability of food to dwindle. Nowadays cockle fishing is banned and
effort is put into the renovation of mussel beds in the Wadden Sea. In this way, the future winter food
supply for Eurasian Oystercatchers can be expected to grow. Besides the risk of starvation, disturbance
that come with living in a densely populated country affect overwintering Eurasian Oystercatcher
populations. An example is the planned deepening of the Oosterschelde. (Bos 2010)
Dutch breeding populations of Common Redshank and Northern Lapwing mainly overwinter
in Western Europe and parts of Africa. Important areas are the Mediterranean region, both the
European and African part, Morocco, the Iberian Peninsula, France, England and restricted parts of
West Africa. One of the threats both species have to deal with during their overwintering period is
hunting, especially in France. In the case of Northern Lapwing, about 480.000 individuals are being
hunted annually in Europe. Furthermore, overwintering Common Redshank populations can be found
in popular holiday destinations. Tourists and recreation therefore cause disturbance. Since
overwintering Northern Lapwing populations are not restricted to wetlands, but can also be found in
agricultural areas, disturbance by recreation and tourists does affect these populations to a lesser
extent. (Bos 2010)
West Africa is of importance for the overwintering Dutch Black-tailed Godwit population. The
floodplains of the river Senegal and the river Niger, but also the areas of rice cultivation in GuineaBissau and the southern part of Senegal annually house high densities of Black-tailed Godwits.
Because the rice cultivation was barely altered through time, these areas are stable overwintering sites.
Conflicts between farmers and birds do occur, since birds tend to trample rice plants and eat sown rice.
The amount of birds that becomes victim to farmers, however, is negligible. At the floodplains of the
river Senegal and river Niger, the main threats are related to the weather. During dry years, the water
table levels of the rivers drop, thereby decreasing the area being inundated and the duration of
inundation. This causes Black-tailed Godwits to concentrate within the limited foraging areas and
increases food competition. In this way, the mortality rate goes up and the condition of birds returning
to the Netherlands is relatively worse, compared to their condition in non-drought years. Besides
drought, human induced alterations to the river deltas, for example dam construction, decrease the area
suitable for overwintering. When discussing the threats concerning overwintering Dutch Black-tailed
Godwit populations, roosting areas have to be taking into account, since birds will stop in countries
like France, Portugal and Spain, before arriving in overwintering areas in Africa. Areas of rice
cultivation in Spain and Portugal, but also wet, ploughed meadows are ideal foraging grounds. In these
areas the main threat is land-use change. Drainage in France has proven to be a threat and with the
revision of the CAP on its way, rice cultivation in Spain and Portugal can be expected to change in the
near future (Brouwer 2005). The effect of hunting on Black-tailed Godwit nowadays is negligible.
(Bos 2010)
38
4.8 Threats – An overview
Now that the most important threats concerning Dutch meadow bird populations were discussed, table
4 gives an overview of these threats, with possible protection measures to counteract these threats. The
last threat in table 4 is not taken into consideration, since the focus of this thesis is on national-scale
threats and protection measures. Furthermore, the table merely gives an overview. Two threats,
vegetation composition and predation, will have to be highlighted a bit more. In the case of vegetation
composition, the joined effect of nutrients and the ground water level play a key role and therefore
protection measures under manuring and dessication can be seen as protection measures to optimize
the vegetation composition. Concerning predation, the limitation of voluntary nest protection will only
be beneficial in areas under management agreements, since the lack of agreements will cause chick
mortality through agricultural practices to exceed mortality through predation if nests are unprotected.
The other protection measures will, if they turn out to be desirable in the chapter on the optimization
of current meadow bird protection, be discussed into more detail there. The following chapter will
further discuss protection measures, but will primarily focus on a scale larger than the individual
protection measure level.
Table 4: Overview of the abovementioned threats concerning Dutch meadow bird populations and possible protection
measures. Based on: Brouwer 2005 and Sanders et al. 2004.
Threat
Habitat loss, fragmentation and
disturbance
Grazing and mowing
Manuring
Desiccation
Vegetation composition
Predation
Overwintering
Protection measures
- Safeguarding important meadow bird areas
- Uncultivated balks, trenches and verges
- Creating continuous grassland areas
into account meadow birds in planning infrastructure
- Placing sound walls
- Introducing resting periods
- Creating safe havens for chicks
- Individual nest protection
- Meadow bird friendly mowing practices
- Avoiding manure injection techniques
- Manuring adult foraging areas
- Avoiding manuring chick lands
- Liming to prevent acidification
- Raising ground water levels
- Inundating fields
- See manuring and desiccation
- Liberizing regulation concerning predation curtailing
- Counteracting predation
- Limiting voluntary nest protection
- Not applicable
- Taking
The threats concerning Dutch meadow bird populations, thus, are very broad. A large part of them is
a direct or indirect effect of modern agriculture, but predation, a non-agricultural threat, also proves
to be an important element. Furthermore, international threats had been described. These threats are
hard to tackle, since they take place outside the Dutch borders. The wide variety clearly indicates the
complexity of meadow bird protection in the Netherlands, since different threats demand different
solutions, but also because threats can be intertwined, as indicated by the joined effect of drainage
and fertilization in determining the vegetation structure.
39
5
Protection measures
40
5. Protection measures
In the previous chapter, an overview of the threats concerning meadow bird populations was given.
This chapter will focus on the most common protection measures that are being taken to counteract
these threats. What protection measures are being taken? Furthermore, the effects of these protection
measures will be discussed. How effective are current protection measures?
5.1 Voluntary meadow bird protection
When speaking of meadow bird protection, it is important to realize that a considerable part of this
protection is performed on a voluntary basis (SOVON 2010). This voluntary meadow bird protection,
according to Handboek Agrarisch Natuurbeheer 1998, comprises the search for and the markation and
protection of meadow bird clutches and chicks. Handboek Agrarisch Natuurbeheer 1998 stated three
forms of voluntary meadow bird protection: nest protection, chick protection and the protection of
parcels of land, of which voluntary nest protection is the most prominent form. During both 2007 and
2008, more than 11.000 volunteers contributed to voluntary nest protection in the Netherlands
(SOVON 2010). This resulted in 117.944 ha of agricultural land under voluntary nest protection in
2008 (SOVON 2010). In the same year, an additional area of 239.713 ha of agricultural land was
under nest protection through the PSAN incentive described before (SOVON 2010). The 117.944 ha
of land under voluntary nest protection comprised roughly one fourth of the total area of the
Netherlands under some form of meadow bird protection (e.g. delayed mowing practices, meadow
bird reserves, etc.) during 2008 (SOVON 2010).
Voluntary meadow bird protection started before national and European scale regulation was
implemented. Figure 14 shows the development of Dutch meadow bird protection through time. The
figure indicates voluntary meadow bird protection as nest protection. The x-axis indicates the
development of Dutch meadow bird protection through time. It is important to realize that the
developing instruments do not replace one another. The y-axis indicates the quality of the instruments
in terms of chick survival. Because both scales are arbitrary, figure 14 should merely be seen as a brief
and simplified overview of Dutch meadow bird protection through time.
Table 5 shows the hatching success of nests with and without voluntary nest protection during
the late 1980’s and late 1990’s for the four focus species of this thesis. According to Teunissen et al.
2004, nest protection resulted in a mean increase of hatching success during the 1980’s. However, this
was caused by a significant increase in the hatching success of Northern Lapwing. The other three
species lacked a significant difference in hatching success between protected and unprotected areas.
On the other hand, nest protection during the 1990’s resulted in significantly increased hatching
successes for all four species. Teunissen et al. 2004 stated that the latter was rather caused by a decline
in the hatching success of unprotected sites from the 1980’s to the 1990’s. Black-tailed Godwit clearly
shows this decline, that, according to Teunissen et al. 2004, was caused by the introduction of manure
injection techniques and advanced field access.
41
Figure 14: The development of Dutch meadow bird protection through time (arbitrary x-axis). The effectiveness in
terms of chick survival has been rising since the initiation of meadow bird protection (arbitrary y-axis). Different
actors, instruments and means of monitoring are indicated. Based on: Moons et al.
Table 5: Mean annual hatching success of Black-tailed Godwit nests during the late 1980’s and late 1990’s. Protected
and unprotected nests were distinguished. Source: Teunissen et al. 2004.
Eurasian
Oystercatcher
Northern Lapwing
Black-tailed Godwit
Common Redshank
1980’s
Protected
1.98
Unprotected
1.33
1990’s
Protected
2.32
Unprotected
1.30
3.14
2.64
2.23
2.57
2.26
2.49
2.86
2.46
3.25
2.23
1.40
2.21
5.2 Agri-environment schemes
Voluntary nest protection is only one mode of trying to increase hatching success. The other way is by
delaying agricultural practices, especially the first mowing practices of the year (Breeuwer et al. 2009;
Kleijn et al. 2004). This type of protection could only evolve after legislation allowed farmers to get
financially compensated for financial losses caused by meadow bird protection, by setting up
management agreements, or so called agri-environment schemes. Like in the case of voluntary
protection, management alterations under agri-environment schemes can be seen as a form of
voluntary meadow bird protection, since farmers voluntarily close agri-environment contracts.
Farmers are, however, obliged to adhere to the set of management prescriptions stated in the
management agreement after sealing it (Kleijn et al. 2001). The postponement of agricultural practices
forms the basis of the schemes, that initially were closed with individual farmers, but could later on
also be closed with agri-environment cooperatives, as shown in figure 14 (Breeuwer et al. 2009; Kleijn
et al. 2001; Kleijn et al. 2004; Moons et al.). Like voluntary nest protection, delayed mowing
practices, and thereby agri-environment schemes, mainly affect the hatching success of meadow bird
species, but one can imagine that chick mortality might also be reduced.
42
Both of these factors seem to suggest that, in order to evaluate the effectiveness of delayed
agricultural practices, one should evaluate at least the effect of these delayed practices on hatching
success. However, my personal impression is that most literature focuses on meadow bird breeding
densities instead. The idea is that if protection measures work, meadow bird populations increase,
thereby increasing future population densities. Sanders et al. 2004 showed that literature indicates a
wide range of results (i.e. both positive, negative, neutral and variable effects) when it comes to the
effect of delayed agricultural practices on meadow bird population densities. Many sources seem to
lack critical information like proper control sites or historical data on population trends (Sanders et al.
2004). Kleijn et al. 2003 performed a literature study on the effects agri-environment schemes have in
Europe. In this study, Kleijn et al. 2003 only included literature that included aspects like proper
control sites and historical data on population trends. The general conclusion was that the study did
not result in an unambiguous view on the effect of agri-environment schemes on, among others,
meadow bird population densities. Both positive, negative, neutral and variable effects on meadow
bird population densities were found. An assessment based on meadow bird population density trends,
thus, does not give a clear view on the effectiveness of agri-environment schemes. This could either
mean that agri-environment schemes are ineffective in enlarging Dutch meadow bird population
densities or could mean that a different indicator is required.
An assessment based on hatching success or the amount of chicks reaching the age of being
fully-fletched might give a better idea on the effectiveness of delayed agricultural practices. The
postponement of agricultural activities to June has proved to reduce nest destruction, thereby
increasing the hatching success (Oosterveld et al. 2007). Furthermore, chick mortality declines
(Beintema et al. 1987; Schekkerman et al. 2007; Schekkerman et al. 2009). Both results suggest the
effectiveness of delayed agricultural practices. However, in order for a measure to be effective in
terms of reproductive output, the annual adult mortality needs to be compensated by at least the same
annual amount of chicks reaching the age of being fully-fledged. Schekkerman et al. 2000 stated that
per breeding pair, in the case of Black-tailed Godwit, 0.6-0.7 chicks reaching the age of being fullyfledged would be sufficient to ensure a stable Dutch population. Schekkerman et al. 2000 and
Schekkerman et al. 2008 concluded that the actual reproductive output is insufficient (i.e. 0.44
fledglings per breeding pair on average) to compensate for the annual adult mortality. In the case of
Common Redshank, Roodbergen et al. 2011 stated that an annual reproductive output of 0.5-1.1
chicks per breeding pair would be sufficient to ensure a stable Dutch population. In this range, a
reproductive output of 0.5 corresponds to the optimistic scenario, whereas a reproductive output of 1.1
corresponds to the pessimistic scenario. A reproductive output of 0.8 chicks reaching the age of being
fully-fledged is the intermediate option and will therefore be used. According to Roodbergen et al.
2011, the reproductive output of Common Redshank under agri-environments schemes is 0.53
fledglings per breeding pair, indicating that the minimum reproductive output needed for a stable
Dutch population is not met. For Eurasian Oystercatcher, Roodbergen et al. 2011 stated that, per
breeding pair, 0.2-1.2 chicks reaching the age of being fully-fledged would be sufficient to guarantee a
stable Dutch population. In this range, a reproductive output of 0.2 corresponds to the optimistic
scenario, whereas a reproductive output of 1.2 corresponds to the pessimistic scenario. A reproductive
output of 0.7 chicks reaching the age of being fully-fledged is the intermediate option and will
therefore be used. Roodbergen et al. 2011 stated that during 1981-2000, the period during which agrienvironment schemes formed the main tool of meadow bird protection (i.e. mosaic management still
had to be developed), the reproductive output of Eurasian Oystercatcher was about 0.35-0.4 fledglings
per breeding pair. Agri-environment schemes therefore are ineffective in guaranteeing a stable Dutch
Eurasian Oystercatcher population. Teunissen et al. 2005 used a reproductive output of 0.8-1 chicks
per breeding pair for Northern Lapwing as a standard. They stated that roughly 14% of all chicks
reaches the age of being fully-fledged. Since, according to Beintema et al. 1995, the average clutch
size of Northern Lapwing is four, this means an annual reproductive output of 0.56 chicks per
breeding pair, which is insufficient to guarantee a stable Dutch Northern Lapwing population.
Beintema et al. 1995 stated that, within the group of meadow bird researchers, one can
distinguish between optimists and pessimists. This seems to be reflected by the lack of an
unambiguous view on the effectiveness of agri-environment schemes. An unsatisfactory result of agrienvironment schemes will cause researchers to fall into the category of the pessimists, whereas a
satisfactory result causes researchers to be reckoned among the optimists. Ranges in the amount of
43
chicks necessary to guarantee stable Dutch meadow bird populations based on different scenarios,
supports the idea of Beintema et al. 1995. However, my opinion as a writer is that the words optimists
and pessimists are judgmental and are the result of data gathered. All researchers are realists rather
than optimists or pessimists in their own view. Reality will likely lay amidst the most optimistic and
most pessimistic scenarios. Different opinions will appear again in the next chapter, when individual
threats will be ranked. Different researchers, thus, also have different opinions on the severity of
individual threats concerning Dutch meadow bird populations.
5.3 Mosaic management
Individual nest protection and delayed agricultural practices, so, prove to be successful instruments in
increasing the hatching success of meadow bird nests. However, the annual reproductive output under
these measures is not sufficient to maintain high meadow bird population densities (Schekkerman et
al. 2000; Schekkerman et al. 2008). Through the set up of agri-environment cooperatives, farmers
were capable of protecting meadow birds in a more collective way. In this way, larger areas could be
included under management agreements and experience could be shared (van ‘t Veer et al. 2007).
Collective management allowed so called ‘mosaic management’ to develop (figure 14) (Moons et al.).
This management type aims at offering a mosaic of vegetation types, thereby offering a constant
minimum amount of so called ‘chick land’ (Oosterveld 20062; Oosterveld et al. 2007; Schotman et al.
2007; Teunissen et al. 2007). Chick land is supposed to be used as foraging area by meadow bird
chicks and aims to provide sufficient food to increase chick survival levels (Schotman et al. 2007;
Teunissen et al. 2007). Initially, the area covered by chick land was stated to be 1 ha per Black-tailed
Godwit family (Oosterveld et al. 2007; Schotman et al. 2007; Teunissen et al. 2007). The adaptation of
mowing practices is the main tool used in creating a mosaic of vegetation types (Oosterveld 20062;
Oosterveld et al. 2007; Teunissen et al. 2007). The development of mosaic management indicates a
shift in management practices. Initially, management focused on increasing hatching success, whereas
mosaic management takes a larger part of the reproductive period into account.
Oosterveld 20062 evaluated the effect of mosaic management by observing the population
trends of the four focus species between 1996-2005. Figure 15 shows the results. In this figure, the
reference year is 2000, the start of mosaic management in the study area. Since the study area is
located within the province Friesland, both the national trends and the Frisian trends are shown. When
the figure is observed, it becomes clear that after the reference year, populations inside the mosaic
areas perform relatively good. Again, it is hard to draw conclusions based on meadow bird densities or
trends, since the positive effect of mosaic management would be expected on chick survival. The
relatively positive trends in mosaic areas shown in figure 15 could have been caused by migration and
data on chick survival within mosaic areas is therefore needed to assess the effect of mosaic
management.
Teunissen et al. 2007 investigated the effect of mosaic management on the survival of Blacktailed Godwit chicks. Schekkerman et al. 2000 showed that the presence of 1 ha of chick land per
Black-tailed Godwit breeding pair does not result in a reproductive output of 0.6-0.7 chicks reaching
the age of being fully-fledged. Only one out of 14 areas reached this minimum reproductive output
needed to compensate for the annual adult mortality. This unsatisfactory result made that the standard
of 1 ha of chick land per breeding pair was believed to be insufficient. Teunissen et al. 2007 used a
standard of 1.4 ha of chick land per breeding pair and investigated chick survival in three different
areas. In two of these areas the reproductive output exceeded the minimum requirement. In the third
case, the amount of chick land did not meet the minimum of 1.4 ha per breeding pair throughout the
breeding season, which might be the explanation for not reaching the minimum reproductive output
required.
Besides the size of the area termed chick land, the spatial distribution plays a key role. This
was shown by Schotman et al. 2007. The results presented show that, in the 15 different areas
observed, the amount of land covered with suitable chick vegetation far exceeded the 1.4 ha per
breeding pair. In this study, the species observed was Black-tailed Godwit. The calculations showed
that the amount of chick land was about 235% of what was required. However, Schotman et al. 2007
44
concluded that only 52% of the Black-tailed Godwit chicks had access to sufficient chick land, either
because chick land was not reachable because of the distance or because food competition within
chick lands was high due to relatively high local breeding densities.
The current state of Dutch meadow bird protection under SNL, that was described earlier,
promotes mosaic management. Meadow bird protection falls under the index agricultural nature
management types. As shown in figure 14, an area-based collective management plan forms the basis
of current meadow bird protection. By, on a large scale, combining different management packages, a
mosaic is created. As described before, management packages will only be compiled in areas that had
been nominated for meadow bird protection by the responsible province. Table 6 gives an overview of
the packages concerning meadow bird protection.
Figure 15: Population trends for the four focus species between 1996-2005. Green lines indicate population trends
within the study areas, whereas the national and Frisian trends are indicated with black and blue lines respectively.
Source: Oosterveld 20062.
When the measures presented in this table are observed, the postponement of agricultural practices,
indicated as ‘resting periods’, seems to play a key role. Package A01.01.01 aims at creating suitable
nesting areas, in which hatching can take place undisturbed. Because not all farmers are willing to
delay farming practices, package A01.01.04 gives them the opportunity to protect meadow birds
through nest protection. Besides promoting hatching success, several packages aim at optimizing chick
survival. These packages are A01.01.02, A01.01.05 and A01.01.06. Grazing, in two of these packages,
will slow down the development of the standing vegetation, thereby causing it to be suitable chick
land later on in the breeding season. The protection of herb-rich vegetation types will have a
comparable effect, since these vegetation types form more suitable chick foraging areas than more
uniform grasslands, as shown earlier. Finally, inundation can be seen as a form of meadow bird
attraction. Meadow birds are known to forage and roost in inundated areas. Inundation might
therefore, by attracting meadow birds, increase the likelihood of these birds to start nesting in
neighboring areas (Index Natuur en Landschap 2012).
45
Table 6: Overview of the management packages for the purpose of meadow bird protection under SNL. Based on:
Index Natuur en Landschap 2012.
Package
Meadow bird area
with resting period
(A01.01.01)
Pre-conditions
Vegetation type:
grassland
Minimum size:
0.5 ha
Measures
Resting period:
no farming practices,
period depends on package
type
Meadow bird area
with early grazing
(A01.01.02)
Vegetation type:
grassland
Minimum size:
0.5 ha
Inundation
(A01.01.03)
Vegetation type:
grassland
Minimum size:
0.3 ha
Resting period:
no farming practices,
period depends on package
type
Before resting period:
grazing
Inundation:
Annual inundation,
period depends on package
type
Agricultural land
with nest protection
(A01.01.04)
Vegetation type:
grassland or arable land
Minimum size:
0.5 ha
Herb-rich
meadow bird area
(A01.01.05)
Vegetation type:
grassland
Minimum size:
0.5 ha
Extensively grazed
meadow bird area
(A01.01.06)
Vegetation type:
grassland
Minimum size:
0.5 ha
Nest protection:
Nest marking,
placing nest defenders,
adapting agricultural
practices
Herbicides:
Creeping Thistle
(Cirsium arvense),
Broad-leaved Dock
(Rumex obtusifolius),
Nettles (Urtica L.)
Fertilization:
solid manure
outside resting period
Resting period:
April 1st – June 15th
Mowing:
Before August 1st
Vegetation management:
Extensive
Grazing:
Until June 15th,
1-1.5 cattle/ha
Resting period:
April 1st – June 15th
Package types
April 1st – June 1st
(A01.01.01a)
April 1st – June 8th
(A01.01.01b)
April 1st – June 15th
(A01.01.01c)
April 1st – June 22nd
(A01.01.01d)
April 1st – July 1st
(A01.01.01e)
April 1st – July 15th
(A01.01.01f)
April 1st – August 1st
(A01.01.01g)
May 1st – June 15th
(A01.01.02a)
May 8th – June 22nd
(A01.01.02b)
February 15th – April 15th
(A01.01.03a)
February 15th – May 15th
(A01.01.03b)
February 15th – June 15th
(A01.01.03c)
February 15th – August 1st
(A01.01.03d)
Grassland
(A01.01.04a)
Arable land
(A01.01.04b)
Herb-rich
meadow bird grassland
(A01.01.05a)
Herb-rich
meadow bird grassland edges
(A01.01.05b)
Extensively grazed
meadow bird area
(A01.01.06)
46
It is clear now that, since considerable parts of the Dutch meadow bird populations are restricted to
agricultural areas, most protection measures aim at reducing the negative effects of agricultural
practices. Initially, meadow bird protection was purely voluntary. After the implementation of
regulation, farmers could be compensated for financial losses caused by meadow bird protection. This
caused meadow bird protection to gain more popularity. Initially, the focus was on protecting nests,
but due to the introduction of mosaic management, chick protection recently gained importance. By
offering a variety of meadow bird protection packages, the Dutch government aims at promoting
mosaic management.
47
6
Optimizing meadow
bird protection
48
6. Optimizing meadow bird protection
The last two chapters discussed the threats and protection measures concerning Dutch meadow bird
populations. In order to optimize meadow bird protection, the threats will have to be ranked. Which
threats put the biggest pressure on Dutch meadow bird populations? Based on this ranking, current
protection measures can be optimized and new protection measures can be implemented. How can
current protection measures be optimized? What new protection measures should be implemented?
6.1 Ranking threats
Now that both the threats concerning Dutch meadow bird populations and the protection measures
have been discussed, the threats can be ranked based on their severity. This ranking is based on four
data sources, showed in table 7. The first source was presented before, in figure 11, and focused on the
hatching success of unprotected nests of Black-tailed Godwit and Northern Lapwing. The second data
source will be presented later on in this chapter (figure 16) and is based on a population model for
Black-tailed Godwit and Northern Lapwing that predicts the effect of individual threats on the amount
of chicks reaching the age of being fully-fledged. The third data source is an article by Terwan et al.
2002, focusing on ranking the threats concerning the survival of Black-tailed Godwit chicks. The last
source is an article by Teunissen et al. 2004 that determined the threats concerning the hatching
success of clutches of the four focus species. Empty sections in table 7 indicate a lack of data. By
comparing the different rankings, it becomes clear that, according to all data sources, predation is an
important loss factor and therefore becomes - - - in the final column, the column with the ranking that
will be used further on. Furthermore, the ranking based on figure 16 shows a clearly distinctive pattern
that can be explained by the fact that the model focuses on the effect of the removal of individual
threats instead of the effect an individual threat has on the reproductive output. Several threats were
only described in one out of four data sources (habitat loss, fragmentation, desiccation and vegetation
composition) and therefore become the values according to these data sources. In the case of
disturbance, half of the data sources assign this threat -, whereas the other half assigns this threat - -.
This results in a rating of -/- - in the final column. Concerning grazing date and grazing density, the
scores in the final column are - - and - - respectively, since these scores best reflect the general view.
When it comes to mowing date, mowing pattern and mowing speed, the scores best reflecting the
general view are - -, - - - and -/- - respectively. Manuring is ranked with -/- -.
As mentioned earlier, different researchers have different opinions, thereby falling into the
category optimists or pessimists, as stated by Beintema et al. 1995. Table 7 shows that, when it comes
to ranking individual threats concerning Dutch meadow bird populations, different rankings exist. By
taking into account different rankings, the ranking used in this thesis will represent the variety of
opinions concerning individual threats.
The threats listed in table 7 are the titles of the paragraphs under the chapter threats. The first
two paragraphs were split into different categories, after Terwan et al. 2002. The term mowing pattern
nowadays corresponds with large areas being mown at once, resulting in vast areas of short vegetation
(Kleijn et al. 2007; Terwan et al. 2002). The other two categories related to mowing, the mowing date
and mowing speed, are less severe, because individual nest protection can limit the negative effects of
early mowing and because meadow bird families can flee to neighboring fields if the area mown at
high speed is limited. Vegetation composition in the table refers to in-field heterogeneity and can thus
be seen as an indicator of habitat quality. Since Teunissen et al. 2007 showed that by increasing the
amount of chick land, compensation for the quality of the land can take place, the vegetation
composition is less important than one could have expected in advance. The larger scale vegetation
composition, however, is an important factor that is mainly determined by the category mowing
pattern and therefore is part of this category.
49
Table 7: Ranking of the earlier described threats concerning meadow bird populations in the Netherlands, according
to four data sources. The fifth column represents the ranking that will be used further on and is based on the four
data sources. Based on: Terwan et al. 2002, Teunissen et al. 2004 and Teunissen et al. 2005.
Threat
Importance
(figure 11)
Habitat loss, fragmentation
and disturbance
- Habitat loss
- Fragmentation
- Disturbance
Grazing and mowing
- Grazing date
- Grazing density
- Mowing date
- Mowing pattern
- Mowing speed
Manuring
Desiccation
Vegetation composition
Predation
Overwintering
Importance
(figure 16)
-
-
- -/- - - -/- - - -/- - - -/- - -
-
--N/A
--N/A
Importance
(Terwan et
al. 2002)
----
---0/--N/A
Importance
(Teunissen et
al. 2004)
-- -/- - - -/- - - -/- - -/- -/- -/- -
- -/- - N/A
Importance
utilized
---/- ------/- -/- 0/--N/A
Legend: (0) indifferent; (-) moderate negative effect; (- -) negative effect; (- - -) strong negative effect.
6.2 Optimizing current protection measures?
The previous chapter clarified that current protection measures, both voluntary protection measures
and protection measures under management agreements, aim at reducing the negative effects of
agricultural practices. According to table 7, the mowing pattern is one of the biggest threats opposing
Dutch meadow bird populations and therefore mosaic management seems to be an appropriate way of
meadow bird protection (Terwan et al. 2002). However, the results by Schekkerman et al. 2000, that
showed that an area of 1 ha of chick land per breeding Black-tailed Godwit pair is insufficient to
ensure a reproductive output of 0.6-0.7 chicks reaching the age of being fully-fledged, indicate that
mosaic management by itself might not be sufficient to ensure stable Dutch meadow bird populations.
Teunissen et al. 2007 showed that a standard of 1.4 ha of chick land per breeding pair could be
sufficient to reach this goal. Still, Teunissen et al. 2007 based their results on a survey in only three
study areas, of which one did not meet the reproductive output of 0.6-0.7 chicks reaching the age of
being fully-fledged. The explanation of this survey area not reaching the standard of 1.4 ha of chick
land per family throughout the reproductive period could be an explanation for not reaching the
desired reproductive output (Teunissen et al. 2007). On the other hand, it could be a sign of the need of
further protection measures.
Teunissen et al. 2005 tested for the hypothesis that, in order to ensure stable Dutch meadow
bird populations, a set of protection measures is necessary rather than a single individual protection
measure. Even though mosaic management can be seen as a way of counteracting only one of the
categories of threats that mowing (i.e. mowing pattern), and thus agriculture, poses, Teunissen et al.
2005 did not distinguish between different forms of agricultural threats. Counteracting agricultural
threats can therefore be seen as a protection measure regardless of the specific method. Teunissen et
al. 2005 tested for the hypothesis using a population model for Black-tailed Godwit and Northern
Lapwing. Figure 16 shows the results of the simulation. By adding or removing threats from the
population model, the effect of protection measures on the reproductive output of Black-tailed Godwit
and Northern Lapwing was determined indirectly, since the effect of the presence or absence of threats
was simulated rather than the effect of protection measures.
50
In figure 16, the threats are separated into threats concerning nests and threats concerning
chicks. For both Northern Lapwing and Black-tailed Godwit, the black bars, termed ‘measured’,
indicate the mean number of chicks reaching the age of being fully-fledged measured during a survey
period. These bars can therefore be considered the current reproductive output in unprotected areas.
The other bars represent the effect of these threats being taken away from the population model, in
terms of the amount of chicks reaching the age of being fully-fledged. Both horizontal bars indicate
the minimum reproductive output needed to ensure stable Dutch populations of Black-tailed Godwit
and Northern Lapwing. One can see that in only one case, the case of removing chick predation by
birds, this minimum reproductive output is realized for both species. It is likely that totally removing
chick predation by birds in real life is impossible, even if measures against this form of predation are
to be taken. The relatively high effectiveness of taking away chick predation by birds is in line with
the ranking in table 7. On the other hand, the mowing pattern, the other important threat (i.e. nest –
agrarian and chick – agrarian), does not show a clearly distinctive bar. Teunissen et al. 2005, as shown
in table 7, therefore consider mowing pattern to be relatively unimportant. The other data sources,
however, cause this threat in this thesis to be ranked as having a strong negative effect on the
reproductive output of Dutch meadow bird populations.
If the results presented in figure 16 are applied to the current measures being undertaken to
protect Dutch meadow bird populations, it seems like current protection measures will not be able to
succeed in guaranteeing the stabilization of Dutch meadow bird populations. By optimizing current
protection measures, the reproductive output will benefit, but since the population model calculated
the effects of the total absence of threats, the effects protection measures will have on the amount of
chicks reaching the age of being fully fledged will not exceed those presented in figure 16.
Figure 16: The effects of the removal of individual threats in the nesting phase and the chick phase, in terms of the
amount of chicks reaching the age of being fully-fledged. The results concern Northern Lapwing (left) and Blacktailed Godwit (right). Horizontal bars indicate the reproductive output necessary for keeping current population
densities. Source: Teunissen et al. 2005.
6.3 Optimizing establishment
When the protection measures described in the previous chapter are observed, it becomes clear that the
only purpose is to protect the breeding birds that are already present. In order for protection measures
to have the maximum beneficial effect, the density of breeding pairs present in the area under
protection should be maximized and therefore measures to reach this goal should be taken. Table 6
contains one package (A01.01.03) that aims at increasing meadow bird establishment through
inundation. This inundation was a natural phenomenon before drainage intensified (Beintema et al.
51
1995). Oosterveld et al. 2007 and Teunissen et al. 2010 showed that inundated fields are popular areas
for foraging and roosting. High densities of meadow birds gather near the edges of inundated areas,
where the highest earth-worm densities can be found. The positive effect of inundation lasts for
roughly three weeks, after which earth-worm numbers are depleted. The most suitable periods for
inundation are half February-half April and half June-half July. Inundation before the breeding period
had proved to be a tool of luring meadow birds into breeding in the close surroundings of the
inundated field and can therefore be seen as a form of meadow bird attraction. Besides the effect
inundation has on the establishment of breeding pairs, it slows down the development of the local
vegetation, therefore making it suitable chick land later in the breeding season. (Oosterveld et al. 2007;
Teunissen et al. 2010)
The fact that the edges of inundated areas attract the highest foraging densities suggests that
high earth-worm densities are the main factor in determining the attraction of adult meadow birds
before the breeding season. As explained before, manuring levels affect the presence of earth-worms
and it therefore could be used in attracting breeding pairs. According to Kleijn et al. 2001, Kleijn et al.
2003 and Oosterveld et al. 2007, the presence of earth-worms is indeed used as a cue for estimating
the suitability of an area as a nesting area. Oosterveld et al. 2007 showed that Northern Lapwings tend
to establish in areas with solid manure application and that other meadow bird species are attracted by
the presence of the relatively early nesting Northern Lapwing. This further increases the positive effect
high earth-worm densities have in meadow bird attraction. The example of inundation, described
above, is an extreme form of the alteration of local hydrology. A slight raise in the local water table
level could result in a better accessibility of earth-worms and can attract meadow birds. Measures
aiming at the increase of earth-worm densities and their accessibility, thus, could be used in attracting
meadow bird breeding pairs.
6.4 Optimizing current protection measures
The optimization of current meadow bird protection could take place by optimizing the current
protection measures and by implementing additional protection measures. The example of the lack of a
significant increase in the amount of chicks reaching the age of being-fully fledged under voluntary
nest protection shows that simple, individual measures are insufficient to secure stable Dutch meadow
bird populations. Figure 16 goes one step further and does not only indicate that simple, individual
measures are insufficient, but also that the total absence of one individual threat is insufficient to
guarantee stable Dutch meadow bird populations. This signals the need for a combination of both an
optimization of current protection measures and the implementation of additional protection measures.
Teunissen et al. 2005 stated that the effect of a set of protection measures will be more positive than
the sum of the positive effects of the individual protection measures making up this set.
In order to optimize the current protection measures, described in the previous chapter, the
first step is to discriminate between effective and ineffective measures. As said, voluntary nest
protection proved to be insufficient in increasing the reproductive output of meadow birds towards the
minimum amount of chicks reaching the age of being fully-fledged needed for stable populations
(Teunissen et al. 2004). The same goes for individual agri-environment schemes (Schekkerman et al.
2000; Schekkerman et al. 2008). However, mosaic management can be seen as an improved version of
meadow bird protection through individual agri-environment schemes. The results of mosaic
management depend on both the area of chick land per breeding pair and on the quality of this chick
land (Kleijn et al. 2007; Verhulst et al. 2008). 1 ha of chick land per Black-tailed Godwit breeding pair
proved to be insufficient, whereas 1.4 ha of chick land per Black-tailed Godwit breeding pair showed
positive results (Schekkerman et al. 2000; Teunissen et al. 2007). These results, however, where based
on a limited dataset so that more research is required in order to conclude if this standard generates
sufficient reproductive output. The quality of chick land concerns the vegetation composition, as
described in the chapter concerning threats. Since this composition is strongly influenced by the joined
effect of fertilization and drainage, the alteration of one of both could affect the vegetation structure
(Kleijn et al. 2009). Because the water table level cannot be regulated on the field-scale, the alteration
of fertilizer application will be more easily applicable. The statement of Kleijn et al. 2009, that
52
fertilization is the factor limiting the vegetation development in areas with artificially lowered water
table levels, clarifies that this alteration will increase the quality of chick land. Besides the quality and
total area of chick land, the spatial organization of the chick land within the mosaic of vegetation types
is important, as shown by Schotman et al. 2007. Chick lands should be accessible and should therefore
not be situated far apart. Also, the presence of chick land should correspond to the local demand.
Popular breeding spots will demand for a relatively large amount of chick land later in the breeding
season and patches of chick land should therefore either be larger or patches should be more abundant
in such areas.
Despite not increasing the reproductive output of meadow birds, voluntary nest protection can
be considered a success in terms of hatching success (Teunissen et al. 2004). This, again, signals the
need for a set of protection measures rather than a single protection measure. The combination of
voluntary nest protection to enhance hatching success and mosaic management to ensure plenty of
chick land, that is currently applied, is an example of a combination of protection measures. In the
case of individual nest protection, optimization should mainly focus on limiting the amount of field
visits, the avoidance of field visits during dusk and minimizing markation time (Brouwer 2005).
Both measures, however, can be considered measures against agricultural threats. Figure 16
indicates that the total removal of agricultural threats has a limited effect on the reproductive output of
Northern Lapwing and Black-tailed Godwit, showing that, besides the optimization of current
protection measures, there is a clear need for additional protection measures.
6.5 Additional protection measures
Since both figure 11, table 7 and figure 16 point out the importance of predation in reducing the
reproductive success of Dutch meadow birds, the lack of widespread protection measures to counteract
this threat seems surprising. However, predation can be seen as a natural process that therefore should
not be restricted in terms of reducing predator populations (Melman et al. 2008). As shown in figure
13, predation seems to increase through time, spreading westwards. Instead of intervening in
established predator populations, the focus could thus also be on reducing the spread, thereby stopping
the westward shift. According to Brouwer 2005, Sanders et al. 2004 and Teunissen et al. 2005, the
openness of the landscape is related to the presence of predators. By maintaining and regaining the
openness of the landscape, predation can thus be reduced. Moreover, voluntary nest protection had
been shown to increase nest predation (Brouwer 2005; Güebler et al. 2012; Teunissen et al. 2007). The
positive effect of voluntary nest protection in areas lacking agreements on the postponement of
agricultural practices does, however, exceed the negative effect of increased predation (Teunissen et
al. 2007). This is not the case in areas with postponed mowing practices, so voluntary nest protection
should be avoided in these areas (Teunissen et al. 2007).
The statement of predation being a natural process can be discussed. Beintema et al. 1995
stated that, because of the earlier access of farmers to their fields, caused by increased drainage,
predators like Red Fox (Vulpes vulpes) also gained earlier access. This shows that predation cannot be
seen as a continuous factor. The predation maps in figure 13 support this view. Also, the fact that
Dutch meadow birds rely on human activity in shaping their habitat, indicates that meadow bird
habitat presently is cultural land rather than natural land. These arguments could be used to justify
measures aiming at meadow bird protection through the reduction of established predator populations,
which, according to figure 11, table 7 and figure 16, would be an important additional protection
measure.
In taking protection measures concerning predation, it is not only important to realize that a
large set of species can be considered predators, but also that predator species can be protected species
(Oosterveld 2011; Duiven et al. 1999; LNV 2002). It has been shown that Red Fox (Vulpes vulpes)
accounts for a significant part of the nest loss in areas with a high nest predation level (Teunissen et al.
2005). In the case of chick predation, the most accountable chick predators have shown to be Common
Buzzard (Buteo buteo), Grey Heron (Ardea cinerea) and Stoat (Mustela erminea) (Teunissen et al.
2005). These four species fall into different protection categories and populations could therefore be
controlled in different ways.
53
In the case of Red Fox, landowners are allowed to regulate local populations through hunting.
Hunting is permitted during autumn and winter, which is believed to minimize the effect hunting has,
since animals shot during this period are young and not yet sexually mature. Instead of removing these
younger animals from the population, the aim should be to reduce the amount of animals capable of
reproduction during April. To reach this goal, hunting should take place during the period FebruaryMay. Hunting during this period results in a reduced total reproductive output. Furthermore, since
proven hunting methods like spotlighting and the construction of artificial earths are prohibited,
hunting could be fine-tuned by increasing the amount of hunting techniques accepted in meadow bird
habitat. (Duiven et al. 1999; LNV 2002; LNV 2009; Oosterveld 2011)
Grey Heron is a protected species under the Dutch ‘Flora- en faunawet’. Nests, however, are
not protected all year round. Landowners are, outside the breeding season, allowed to remove nesting
trees and nests. Before doing this, the surrounding area needs to be checked for possible alternative
nesting sites. If no possible nesting sites are present, the removal of nesting trees and nests is
prohibited. An independent ecologist could carry out the survey. (Oosterveld 2011)
In the case of Common Buzzard, this species is protected under the Dutch ‘Flora- en
faunawet’. In contrast with Gray Heron, nests are protected all year round. Dispensation is needed to
be able to remove nesting trees and nests outside the breeding season. In order to be eligible for
dispensation, alternative nesting sites will have to be present in the neighboring area. Furthermore, it
will have to be demonstrated that Common Buzzard is a source of nuisance and that other measures
have been taken to protect, in this case, meadow bird populations. Because roughly 60% of nests of
Common Buzzards is situated at preexisting nesting sites, the removing of nests is an effective way of
protecting meadow bird populations. Provinces are responsible for granting dispensation. (Oosterveld
2011)
Stoat is protected under the Dutch ‘Flora- en faunawet’. It is, however, permitted to decrease
the suitability of a certain area in order to decrease the suitability of this area as Stoat territory. For
this, no dispensation is needed and measures are relatively simple. Some examples are: the removal of
wooded banks, old stables, vast areas of reed, etc. The removal of these (vegetation) structures
diminishes the availability of hunting infrastructure and suitable nesting spots. (Duiven et al. 1999;
Oosterveld 2011)
6.6 Site selection
Besides the attraction of breeding pairs and the measures being taken to protect these breeding pairs
and their offspring throughout the breeding season, the location of the areas protected under SNL are a
key factor. It was stated that meadow bird attraction is one way of optimizing the positive effects
protection measures have on the reproductive output of meadow birds. Instead of purely focusing on
the attraction of breeding pairs, the selection of areas that already house high numbers of breeding
meadow bird species could increase the positive effects protection measures have on the reproductive
output. In the ideal situation, a combination of both meadow bird attraction and accurate site selection
will result in nesting areas with meadow birds breeding at carrying capacity. Dutch provinces should
nominate ‘meadow bird hotspots’ as eligible for subsidy under SNL. Since different meadow bird
species have different habitat preferences, the variety of vegetation types that develops under mosaic
management will provide suitable habitats for different species.
Not only the area eligible for mosaic management, but the design of these areas is also
important. The accessibility and availability of chick land had been discussed. The management
packages described in table 6, however, are multiple. It therefore is important to determine the ideal
mix of management packages in terms of, for example, percentages of the total mosaic area. In this
way, mosaic areas can be organized in an optimal way.
Several studies showed that meadow birds tend to return to the same breeding ground annually
(Groen et al. 2002; Kleijn et al. 2003; Swagemakers et al. 2009). This indicates that site selection is a
process that should aim at protecting meadow bird hotspots and at organizing an optimal mosaic that is
constant through time. By offering suitable nesting areas at a fixed location through time, protection
measures causing increased breeding success can increase meadow bird breeding populations through
54
time. Eventually, this process will cause meadow bird populations to breed at carrying capacity. These
populations will then become so called ‘source populations’, that produce offspring that will be forced
to breed in so called ‘sink areas’. These areas contain lower breeding densities and will benefit from
the protection measures in the source area.
6.7 Multi-Criteria Analysis (MCA)
The previous paragraphs described the different factors that should be taken into account in order to
successfully protect Dutch meadow bird populations. These factors can be interpreted in several ways,
resulting in different sets of protection measures. This paragraph will refer to these sets as designs. A
Multi-Criteria Analysis will be performed in order to pick the design most suitable for the protection
of Dutch meadow bird populations. Before performing the MCA, the different designs will be
introduced (table 8).
Design 1 represents the current state of Dutch meadow bird protection and offers a reference
design. In this design, the aim is to create a mosaic of vegetation types throughout the breeding season,
using the management packages presented in table 6. The standard of 1 ha of chick land per breeding
pair is used and problems like predation and the inaccessibility of chick land are not addressed.
Design 2 represents an improved version of design 1. In this case, individual nest protection
will take place in areas lacking postponed grazing and mowing. Markation points will be removed if
threats disappeared. The search for nests will be banned during the late afternoon and evening, since
most mammal species become active then. The amount of field visits will be minimized and these
visits will take place in an inconspicuous way, by walking in straight lines and with regular stops. In
this way, predation losses caused by nest protection will be minimized. Besides this, the standard of 1
ha of chick land per breeding pair is increased towards at least 1.4 ha per breeding pair. Instead of
solely paying attention to the area of chick land present, the accessibility and spatial organization will
be taken into account to guarantee an optimal mosaic. Attraction measures, lacking in design 1, will be
taken in the form of inundation or increased fertilization and water table level elevation. The
inundation is part of design 1, since it is included in one of the packages presented in table 5. In design
2 it will be obligatory to incorporate inundated areas into the mosaic near nesting hotspots.
Alternatively to inundation, the elevation of the water table level and fertilization will have to be
implemented near nesting hotspots.
Design 3, like design 2, represents an improved version of design 1. Instead of aiming at the
attraction of birds to increase the effect of mosaic management (design 2), design 3 incorporates
protection measures against both nest and chick predation. Specific measures will include hunting, the
removal of nests, the removal of nesting trees and maintaining or regaining the openness of the
landscape.
The idea behind design 2 and 3 is that both the obligatory attraction measures and additional
protection measures against predation will decrease the willingness of farmers to participate in
meadow bird protection under SNL and that a design containing a combination of both will therefore
be unrealistic.
Now that the different designs were explained, table 9 presents the MCA. Three criteria (i.e.
nesting density, reproductive output, feasibility) with different weights were used to test for the
effectiveness of the designs. The criterion ‘feasibility’ has the highest weight (0.50), since the extent to
which a design is applicable determines the success of a design. In the case of design 2, the feasibility
is relatively low (+). This is caused by the attraction measures, that will not be achievable in every
situation. The criterion ‘reproductive output’ stands for the goal of the designs and therefore has a
weight (0.40) just below the weight of feasibility. The effects of the designs on this criterion rises from
design 1 (+) towards design 3 (+ + +). The lowest weighted criterion (0.1), ‘nesting density’, focuses
on attraction measures. The fact that meadow bird attraction has no direct effect on meadow bird
protection accounts for the low weight of the criterion. Design 2 performs in the best way under this
criterion (+ + +), since the focus of the design is on meadow bird attraction. Design 3 has a slightly
better performance under this criterion (+/+ +) than design 1 has (0/+), because a better score on the
55
criterion reproductive output can be expected to result in the attraction of higher future breeding
densities of meadow birds.
The abovementioned weights represent one of the two scenarios in table 9 (‘weight 1’,
‘score (weight 1)’). The other scenario (‘weight 2’, ‘score (weight 2)’) contains different weights, with
the criterion reproductive output being the most important (0.5), followed by feasibility (0.3) and
nesting density (0.2).
Table 8: Descriptions of the three different meadow bird protection designs used in the MCA.
Design
Design 1
Design 2
Measures
- Individual
- nest protection
- Mosaic - management
- Individual -------nest protection
- Mosaic
- management
Design 3
- Individual -------nest protection
- Mosaic
---------management
- Predation --------- -measures
Improvements
-
Attraction measures
-
- Unprotected fields
- Limited markation time
- Inconspicuous field visits
- Limited field access
--------- --- (number and time)
- > 1.4 ha chick land/breeding pair
- Accessibility
- Spatial organization
- Unprotected fields
- Limited markation time
- Inconspicuous field visits
- Limited field access
-------------(number and time)
- > 1.4 ha chick land/breeding pair
- Accessibility
- Spatial organization
- Hunting
- Removal nests/nesting trees
- Openness
- Obligatory --------------- inundation
- or
- Elevated water --------table- and ---------------fertilization levels
-
Table 9: MCA of the three designs presented above. The designs were evaluated on three criteria with different
weights.
Criteria
Nesting density
Reproductive output
Feasibility
Score (weight 1)
Score (weight 2)
Design 1
0/+
+
+++
0.4875
0.375
Design 2
+++
+/+ +
+
0.35
0.4125
Design 3
+/+ +
+++
+++
0.7125
0.675
Weight 1
0.10
0.40
0.50
Weight 2
0.20
0.50
0.30
Legend: (0) indifferent/not feasible, score: 0; (+) moderate positive effect/partially feasible, score: 0,25; (+ +) positive
effect/largely feasible, score: 0.50; (+ + +) strong positive effect/feasible, score: 0.75. 0/+ and +/+ + have scores of 0.125
and 0.375 respectively.
The scores showed in table 9 are the weighted summations for all three designs. It turns out that design
3 is, according to both scenarios in the MCA, the best option when it comes to meadow bird
protection. It is important to realize that the effect of design 3 could be optimized if regulation
concerning the measures that are allowed to minimize predation will be liberalized in important
meadow bird areas (Oosterveld 2011). Furthermore, protection measures could be specified, based on
the regional set of predators. It was shown before that the range of predators is broad and that the
predation pressure differs regionally (Teunissen et al. 2005). In the ideal situation, a national
procedure concerning predation measures, that could be applied nationwide, would be developed.
56
Regional differences, however, indicate the need of a regional approach (Teunissen et al. 2005). Since
provinces determine the areas eligible for financial compensation for meadow bird protection and map
these regions, it is recommended for the Dutch provinces to map predation levels in these regions.
Furthermore, an inventory of the species responsible for predation in meadow bird areas should be
performed. In this way, the Dutch provinces can guide farmers in minimizing the effect predation has
on the reproductive output of Dutch meadow bird populations.
It turns out that the removal of a single threat opposing Dutch meadow bird populations is insufficient
to guarantee stable meadow bird populations. Since predation is responsible for a large part of the
losses of nests and chicks, measures aiming at minimizing predation will have a relatively large
positive effect on the reproductive output of Dutch meadow bird populations. The MCA demonstrates
that an optimization of mosaic management combined with measures to tackle predation is the most
effective way of protecting meadow birds. Since predation levels and the set of predators responsible
for predation vary throughout the Netherlands, a provincial based mapping system should be
developed in order to advice farmers on specific measures that could be taken to tackle predation.
57
7. Discussion and conclusion
Current protection measures concerning Dutch meadow bird populations aim at the protection of nests
and chicks through the development of a mosaic of different vegetation types combined with voluntary
nest protection. Under SNL, six different management packages were invented, with the goal of
financially compensating farmers that take part in mosaic management. Mosaic management can be
seen as an optimized form of the individual agri-environment schemes that were first implemented
after the introduction of the Dutch Relatienota. Despite this optimization, the reproductive output of
the four focus species of this thesis will need to be optimized in order to guarantee stable Dutch
populations. The problem with the available data on the effect mosaic management has on the
reproductive output is that the focus is on the development of breeding populations through time.
Since the aim of the combination of individual nest protection and mosaic management is to increase
the reproductive output of Dutch meadow bird populations, the focus should be on monitoring the
reproductive output in terms of the number of chicks reaching the age of being fully-fledged instead.
In spite of research indicating the tendency of meadow birds to nest in the area they hatched, the
availability of earth-worms and the carrying capacity of a breeding area are key element in the
selection of a nesting spot. These factors might cause meadow birds to shift their nesting location
through time, independent of the nesting success.
Another problem with the monitoring of the success of mosaic management is that most data
applies to Black-tailed Godwit. In the case of the four focus species of this thesis, Black-tailed Godwit
will be representative to a high degree, since all species are waders. However, the term meadow birds
was shown to be a very broad term. Data concerning Black-tailed Godwit will therefore not be
representative for all meadow bird species. And also within the group of focus species of this thesis,
differences exist. Data on the effectiveness of mosaic management on the reproductive output of
species other than Black-tailed Godwit is thus desirable. Conclusions being drawn in this thesis can
thus not be seen as conclusion concerning meadow birds in general, since the focus of this thesis was
on a limited set of bird species. Furthermore, because national-scale threats and protection measures
concerning meadow bird populations in agrarian areas were discussed, threats in overwintering spots
and the situation in meadow bird reserves were discussed briefly or were not discussed at all.
The general view on the effectiveness of mosaic management in terms of the reproductive
output is variable and depends on the connection between the amount of chick land per breeding pair
and the quality of this chick land. A standard of 1 ha of chick land per breeding pair throughout the
breeding season proved to be insufficient, whereas a standard of 1.4 ha of chick land per breeding pair
showed more positive effects. Again, this standard concerns Black-tailed Godwit. The MCA
performed in the previous chapter indicated that, in order to optimize the protection of Dutch meadow
bird populations, the combination of mosaic management and voluntary nest protection should be
further optimized. Furthermore, measures against predation should be taken, since the removal of a
single threat will be insufficient to guarantee stable Dutch meadow bird populations.
Since the set of predators and the predation pressure differ throughout the Netherlands, a
national approach is not feasible. Instead, a provincial approach is advised, also because the provinces
determine the areas eligible for financial compensation for meadow bird protection. By not just
mapping the areas eligible for financial compensation, but by also performing surveys on provincial
predation patterns, provinces can advice farmers in fighting meadow bird predation. Before data on
local predation is gathered, more general measures, described in the MCA, can be taken to tackle
predation.
Besides drawing up an inventory on local predation to maximize the effectiveness of measures
aiming at minimizing predation, the current measures allowed should be liberalized in important
meadow bird areas. It will be virtually impossible to totally remove the negative effects predation has
on Dutch meadow bird populations, but by maximizing the effectiveness of measures, the negative
effect of predation could be minimized. The recommendations that were made in the previous chapter
(e.g. increasing the amount of hunting techniques permitted or shifting hunting practices towards the
breeding season), however, are illegal right now. Social resistance is likely to occur if the introduction
of the recommendations will take place and it therefore seems necessary to raise public support before
implementation takes place.
58
In the previous chapter, it was assumed that an approach combining both obligatory meadow
bird attraction measures and additional measures to counteract predation was not feasible. This
assumption was based on the obligatory character of the attraction measures and the additional work
that goes with measures against predation. It might, however, turn out to be possible to combine both
designs in certain areas where farmers are willing to cooperate. Since the effect of a set of protection
measures will be more positive than the sum of the positive effects of the individual protection
measures making up this set, such a design will be preferred.
In order to be able to say something on the effectiveness of the advised design, there has to be
a goal. The reproductive
http://www.telegraaf.nl/mijnbedrijf/article20801349.ece
output of 0.6-0.7 Blacktailed Godwit chicks
reaching the age of being
fully-fledged
is
an
example of such a goal.
This goal aims at
stabilizing
the
total
current Dutch Blacktailed Godwit population.
Of course the aim has to
be high, but the CAPdriven
agricultural
intensification during the
second part of the last
century showed that
Dutch meadow bird
populations are very
sensitive when it comes
to changes in agricultural
practices. More recent
forms of agricultural
extensification
(e.g.
decreased
livestock
densities and decreased
fertilizer
application)
offer hope when it comes
to Dutch meadow bird
populations,
but
a
growing
world
population,
with
an
expected growth of two
billion people by 2050,
will
require
the
availability of food to
rise. The newspaper
article presented here,
that
was
recently
published
in
‘De
Telegraaf’, clarifies this.
It is impossible to predict
the future, but since the Netherlands forms the second largest exporter of agricultural products, it is
likely that a growing demand for these products will affect the Dutch agrarian sector (Rijksoverheid
20122). Extensive farming practices, necessary for Dutch meadow bird populations to bloom, thus,
could become scare. My opinion, as a writer, therefore is that goals concerning the protection of Dutch
meadow bird populations aiming at maintaining these populations at the current, relatively high
population densities, could prove to be unrealistic in the near future. It is obvious that protection
59
measures should be optimized. But not reaching the goal of, in the example of Black-tailed Godwit, an
annual reproductive output of 0.6-0.7 chicks reaching the age of being fully-fledged per breeding pair,
should not be termed unsuccessful. Dutch meadow bird populations are the victim of changes in Dutch
agricultural practices, and historical, pre-‘meadowbirdification’ population densities, rather than more
recent, relatively high meadow bird population densities, should be taken as reference values
(Beintema et al. 1995).
The goal of this thesis was to evaluate the current state of Dutch meadow bird protection and
to give recommendations for the optimization of this protection. What is the most effective way of
protecting meadow birds (i.e. Black-tailed Godwit (Limosa limosa), Common Redshank (Tringa
totanus), Eurasian Oystercatcher (Heamatopus ostralegus) and Northern Lapwing (Vanellus vanellus))
in the Netherlands? It turned out that current protection measures aim at reducing the negative effects
of agricultural practices. However, when the amount of chicks reaching the age of being fully-fledged
was observed, this reproductive output proved to be insufficient in most cases. Still, there seemed to
be a tendency of increasing chick survival through time. The MCA indicated that a combination of
both the optimization of current protection measures and the implementation of protection measures to
counteract predation will be the most effective way of protecting Dutch meadow bird populations and
this. This simultaneously forms the general conclusion of this master’s thesis. Since predation levels
and the set of predators responsible for predation vary throughout the Netherlands, a provincial based
mapping system could be developed in order to advice farmers on specific measures that could be
taken to tackle predation.
60
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