Download Conservation Impact Report 2016

Berkshire
Buckinghamshire
Oxfordshire
Conservation Impact Report 2016
Berks, Bucks & Oxon Wildlife Trust
T. Beckett, D. Lewis, M. Jackson, A. Coulson-Phillips
Protecting local wildlife
Abstract
This report provides a summary of the impact of
conservation work conducted by the Berkshire,
Buckinghamshire and Oxfordshire Wildlife Trust
(BBOWT). The aim of the report is to demonstrate that a
conservation strategy can have a significant impact on
nature, and that in a period where nature is in decline
these efforts are more important than ever.
management practices. As BBOWT has adopted
relatively low input conservation strategies that can be
used alongside hay making and grazing management,
the report presents these as options many landowners
could take up.
Fen, reedbed, wet grassland, lowland heath, pond, lake
and river species are under threat from habitat loss and
declining water quality: all these habitats require some
form of national protection.
This report identifies seven different habitats managed
by BBOWT where a conservation strategy has been put
in place. It reveals that these strategies have a positive
impact on indicator species. The report also reviews
these habitats within a national context.
The landholdings analysed in this report represent
some of the last havens for nature in the three counties.
What is required are joined up habitats allowing for
ecological connectivity across a landscape. It is hoped
that this report demonstrates that conservation
strategies have tangible benefits to wildlife that are
worthwhile taking.
The report concludes that in the wider countryside
species associated with woodlands, calcareous
grasslands, meadows, hedgerows, farmland and
rough grasslands, are in decline due to changes in
Chalk-fragrant orchids
1
Introduction
In the UK, which has the best studied wildlife in the
world, between 1970 and 2013 56% of monitored
species have declined1. Due to the pressures of
changing land use, biodiversity is in decline; the rate
of species extinction in England is probably around a
species each month, and possibly double that2. Climate
change is already affecting our wildlife, and some
species will struggle to adapt in a landscape where
suitable habitats are isolated. This fragmentation is
particularly bad in Berkshire, Buckinghamshire and
Oxfordshire, where only 2% of our land is considered
rich enough in wildlife to be given national protection.
The Berkshire, Buckinghamshire and Oxfordshire
Wildlife Trust manages over 2,500 hectares (0.5%) of
land in the three counties. Our reputation for careful
stewardship of land for wildlife and people has grown
significantly in recent years, and the landholdings
managed by the Trust have increased by 47% since
2012.
Every three years we carry out an internal audit of the
‘health’ of the wildlife we are directly responsible for.
The 2015 audit shows land management carried out by
BBOWT has improved the value of our land for wildlife
across the landholdings. This is in strong contrast to
the general backdrop of decreasing biodiversity in the
three counties.
For butterflies alone, more than three-quarters of the
species found in the UK have declined over the last
40 years3. Locally we have lost species like the pearlbordered and small pearl-bordered fritillary during the
last 10 years. In the last two years we have probably
seen the last marsh fritillary in our three counties. This
iconic species has not been seen at its only known
breeding site at all this year.
This report was compiled by our professional staff and
volunteers, with data from thousands of individual
surveys. By assessing our nature reserves using an
approach similar to the way government bodies, such
as Natural England, assess protected areas, BBOWT
has determined how many of our nature reserves have
wildlife in a good, healthy condition; and thus how
effectively our land management conserves wildlife.
This assessment is based both on the population trends
of individual indicator or specialist species and the
habitats in which they thrive.
Of nearly 8,000 species assessed using modern IUCN
Red List criteria, an accepted system for identifying
species under threat, 15% are threatened with
extinction in Great Britain4. 27.5% of British birds are
now on the Red List of conservation concern5 because
of population or range declines in the UK, or because
of their global population status. Losses of species
will have “potentially serious consequences for the
resilience of ecosystem functions on which humans
depend”, particularly in respect of pollination, pest
control and cultural values6.
1 D.B. Hayhow et al., State of Nature 2016,The State of Nature Partnership, 2016
2 C. Hambler, Evidence-based or Evidence-blind? Priorities for Revitalising Conservation, ECOS 36(3/4) p 22 – 25.
3 The State of the UK’s Butterflies 2015, Butterfly Conservation, 2015
4 D.B. Hayhow et al., State of Nature 2016, The State of Nature Partnership, 2016
5 M Eaton et al., Birds of Conservation Concern 4: The Population Status of Birds in the UK, Channel Islands and Isle of Man, British Birds 108, December
2015, p. 708–746
6 T.H. Oliver et al., Declining Resilience of Ecosystem Functions Under Biodiversity Loss, Nature Communications 6, 2015
2
Woodland
Conservation Status
Conservation Strategy
9.9% (1.3 million hectares) of England is woodland7, but
only 1.2% is semi-natural ancient woodland, around
158,000 hectares8. The structural diversity of woodland
provides niches for a huge range of species, and for
some types of species, such as lichens, woodlands
provide the most diverse habitat9.
Maintaining the diversity of woodland means some
areas are left to their own devices, while others need
intensive management to keep them in favourable
condition, and thus supporting rare and specialist
woodland wildlife. Woodland management primarily
consists of keeping a network of open, sunny rides and
rotational coppicing.
Woodlands support a diverse range of specialist
species including silver-washed fritillary (a species
which declined in the 20th century, but has increased
its range more recently10) willow warbler (an Amber
list species, which has had a modest decline in recent
years, with populations in the south east suffering
most11) and Bechstein’s bat (one of the UK’s rarest
mammals, with possibly only 1500 adults in the
entire population12). 11% of all woodland species are
threatened with extinction in Great Britain13.
In the first years following coppicing these areas are
flooded with sunlight allowing woodland flora such
as primroses and violets to flourish. As the trees start
to regrow, dense patches of scrub develop creating
the ideal conditions for dormice and birds such as
warblers. Some of the timber generated is stacked up
and allowed to rot down naturally, providing a home
for fungi and invertebrates. Scallops or bays along the
edges of rides are also cut on rotation, ensuring that
the rides slowly grade into the mature woodland, thus
providing a wide range of environmental conditions,
ideal for invertebrates and birds.
BBOWT manages 997ha of woodland, 479ha of which are classified as Ancient Woodland.
95% of BBOWT woodlands are classified as favourable or recovering.
Woodland ride
3
Conservation Impact
■■ Management of woodland rides has provided
the ideal ecological requirements for woodland
butterflies such as silver-washed fritillary (Argynnis
paphia). 15 woodland nature reserves support
populations of silver-washed fritillaries. 13%
are new populations with these sites being
colonised since 2002. 93% of silver-washed fritillary
populations are either increasing or stable (see
Figure 1).
Figure 1. Silver-washed fritillary population
trend at a nature reserve colonised in 2009
(r=0.79, P=6.7E-05)
■■ 6 woodland nature reserves support dormice
(Muscardinus avellanariu) populations. Population
trends are mixed across these sites. The
introduction of an active coppice regime at one
site has resulted in a population increase (mean
number of dormice per box was 0.005 in 2006,
and 0.074 2015). Other populations on sites with
similar management interventions are in decline.
This is possibly as a result of wetter, milder winters
(driven by climate change) increasing hibernation
mortality.
■■ Willow warbler (Phylloscopus trochilus) populations
on woodland nature reserves have remained stable
between 2007 and 2015.
Silver-washed fritillary
7 Woodland Area Stats 2010, Forestry Commission, www.forestry.gov.uk/pdf/NFI England_woodland_area_stats_2010_FINAL.pdf
8 UK Woodland Habitats, Joint Nature Conservation Committee, 2013, http://jncc.defra.gov.uk/page-1437, (accessed 12 March 2016)
9 C. Hambler, Evidence-based or Evidence-blind? Priorities for Revitalising Conservation, 2015, ECOS 36(3/4) p. 22 – 25.
10 The State of the UK’s Butterflies 2015, Butterfly Conservation, 2015
11 The Breeding Bird Survey 2015, British Trust for Ornothology
12 S. Harris et al., A Review of British Mammals: Population Estimates and Conservation Status of British Mammals Other Than Cetaceans, JNCC, 1995
13 D.B. Hayhow et al., State of Nature 2016, The State of Nature Partnership, 2016
4
Meadows
Conservation Status
Conservation Strategy
Historically meadows were a major part of England’s
landscape. However, between the 1930s and 1987,
97% of England and Wales’ semi-natural grasslands
were lost14. This decline has continued apace with the
overall extent of UK meadows declining by 2-10% in
some parts of the UK per annum since 198415, making
this habitat particularly important.
Since 2004 BBOWT has carried out 78ha of meadow
creation on land that was previously arable.
Hay meadow communities have evolved and thrived
over hundreds of years of traditional management, and
continuation of this is essential for the survival of the
community. Hay meadows are particularly susceptible
to changes in hydrology, such as summer flooding,
which can prevent traditional management. Hay
meadow management usually consists of an annual
hay cut in mid-July, followed by aftermath grazing with
cattle, or occasionally sheep, that graze the grassland
through until the autumn. These two strategies are
essential in removing nutrients from the system, which
if left, would encourage the dominance of coarser
grasses and weeds to the detriment of the more poorly
competitive wildflowers.
13% of grassland and heathland species are threatened
with extinction in Great Britain16. Meadows are
floristically diverse and support a range of threatened
flora, including the nationally vulnerable true fox sedge
(Carex vulpina) and green-winged orchid (Anacamptis
morio) (vulnerable in England). Both these species
are especially important within an English context
as England supports a significant proportion of the
British population. Meadows also support birds of
conservation concern such as the recently Red listed
curlew (Numenius arquata)17.
BBOWT manages 499 hectares of meadow, including 10% of the remaining floodplain meadows (MG4)
found within England. 94% of BBOWT meadows are classified as favourable or recovering.
Ridge and furrow at a hay meadow
5
Conservation Impact
Snakes-head fritillaries
■■ On areas restored to meadow communities from
arable; characteristic species indicative of MG4 and
MG5 meadows dominate, bird’s-foot trefoil (Lotus
corniculatus) is over 60% abundant and common
knapweed (Centaurea nigra) over 30% abundant.
■■ Green-winged orchid (Anacamptis morio)
populations are located on at least five meadow
sites. Populations vary greatly on an annual basis,
but on average number in their thousands.
■■ One meadow site supports a nationally significant
population of snake’s-head fritillary (Fritillaria
meleagris). The population varies annually as a
result of changes in the hydrological conditions,
such as prolonged flooding. However, meadow
management through taking a hay cut and
aftermath grazing is essential to provide the
environmental conditions required by the species
(see Figure 2).
Figure 2. Snakes-head fritillary population trend on one meadow site
14 R.M. Fuller, The Changing Extent and Conservation Interest of Lowland Grasslands in England and Wales: A Review of Grassland Surveys 1930–1984,
1987
15 UK Biodiversity Action Plan; Priority Habitat Descriptions. BRIG (ed. Ant Maddock) 2008 UK Biodiversity Action Plan; Priority Habitat Descriptions.
BRIG (ed. Ant Maddock) 2008.(Updated July 2010)
16 D.B. Hayhow et al., State of Nature 2016, The State of Nature Partnership, 2016
17 M Eaton et al., Birds of Conservation Concern 4: The Population Status of Birds in the UK, Channel Islands and Isle of Man, British Birds 108, December 2015, p. 708–746
6
Lowland Heaths
Conservation Status
Conservation Strategy
Lowland heathland covers 58,000ha18 in England.
Like many other semi-natural habitats heathland has
experienced a significant contraction in its range,
decreasing by 60% since the 19th century19. 13% of
grassland and heathland species are threatened with
extinction in Great Britain20.
Conservation grazing and rotational cutting of heather
help to ensure heather is present in a range of different
growth stages from very young and short to more
mature and bush forming. This provides the right
conditions for a range of different species that are
adapted to thrive in all stages of heather. Additionally
scrub and gorse are controlled and managed to ensure
that they do not start to dominate, shading out the
heather, but that some is present in dense blocks or as
single trees, providing perches and safe nesting sites
for a range of bird species and refuges for reptiles.
The UK has a special responsibility to conserve and
protect this habitat as it supports about 20% of the
lowland heathland found across Europe. Heathland is
also important in an historical context as much of this
habitat developed during Neolithic and Bronze Age
forestry clearances.
Many of the species associated with heathland are
susceptible to disturbance caused by visitors and dogs.
The wardening of sites and the focusing public access
away from key areas plays an increasingly important
role in helping the survival and breeding success of
these species.
Heathland supports a range of specialist species
including birds such as nightjar (Caprimulgus
europaeus) and Dartford warbler (Sylvia undata), all of
which are currently under threat. Other species include
invertebrates such as silver-studded blue (Plebejus
argus), keeled skimmer (Orthetrum coerulescens) and
small red damselfly (Ceriagrion tenellum) as well as a
range of herpetofauna including the increasingly rare
adder (Vipera berus).
BBOWT manages 445 hectares of lowland heath.
91% of BBOWT lowland heathland is classified as favourable or recovering
Heathland nature reserve
7
Conservation Impact
■■ 90% of BBOWT’s of heathlands support adder
(Vipera berus) populations. On one site, adders
have been radio tracked to assess their response
to habitat management and conditions. The
evidence showed that males travel further than
females (6.7m and 4.7mper day respectively); males
travelling further to find mates. Movement was
also significantly restricted by wide open, short
grassy areas which provide little protection from
predation.
■■ In 2010 silver-studded blue (Plebejus argus)
colonised heathland adjacent to an existing
population. Heather cutting to provide the
required pioneer heather has helped the species
to spread across the site. The population is also
increasing in abundance. Following colonisation
the previous year the maximum individual day
count was four in 2011; in 2015 this had increased
to 14.
■■ 50% heathlands support nightjars (Caprimulgus
europaeus). In 2015 18 pairs were recorded.
Populations at three sites are stable, one is
declining and the final site is increasing (see figure
3). The increase is partly due to site wardening and
improved habitat management.
Nightjar
Figure 3. Trend in number of churring Nightjar at one heathland nature reserve
18 Extent & Distribution of UK Lowland Heathland Habitats, Joint Nature Conservation Committee, jncc.defra.gov.uk/page-5941, (accessed 12 August
2016)
19 N.C. Symes J. and Day, A Practical Guide to the Restoration and Management of Lowland Heathland, 2003,The RSPB
20 D.B. Hayhow et al., State of Nature 2016, The State of Nature Partnership, 2016
8
Ponds, lakes and rivers
Conservation Status
Conservation Strategy
This habitat group covers a wide range of freshwater
habitats, including chalk streams. England has more
chalk rivers than any other country in Europe21, but in
2014 more than three-quarters (77%) of England’s chalk
streams were failing to meet the required “Good” status
required by the Water Framework Directive22.
This diverse range of aquatic habitats is managed
using a variety of different techniques. The focus is
often on striking a balance between providing dense
scrubby margins and open sunlit margins filled with
wildflowers. This is often achieved by rotational scrub
control. Creation of bare ground for associated ground
nesting birds is also important as is the creation of new
ponds.
Water bodies support a diverse range of species
from aquatic invertebrates such as caddisflies and
dragonflies to fish such as bullhead and brown trout.
13% of freshwater and wetland species are threatened
with extinction in Great Britain23.
Co-ordinated control of American mink across whole
river catchments is pivotal in protecting water vole
populations from this voracious predator. Floating
mink rafts are used to monitor and trap mink. Mink
control is co-ordinated strategically, with 160 rafts
carefully located across Berks, Bucks and Oxon.
Working closely with the 57 landowners currently
involved is also essential to the success of this strategy.
These habitats are also essential for mammals such
as water vole and otters. While otters have made a
significant population recovery from virtual extinction
across most of England in the 1970s (58.8% positive
site records in 2009-1024), water voles continue to be
under threat. In 2012 the National Water Vole Mapping
Project, indicated that during the previous three years,
water vole presence had declined by 22% across
England and Wales.
Many lakes also support a wide range of breeding and
over wintering birds, including some species that are
nationally under threat, such as pochard, the status of
which has recently moved from Amber to Red25.
BBOWT manages 137ha of ponds, lakes and rivers:
92% of which is classified as favourable or recovering.
9
Water vole
Conservation Impact
■■ Local Key Areas for water voles (Arvicola
amphibious) increased by 10% between 2012 and
2015, extending from 506 to 560 km2 (see Figure 4
below).
■■ In 2010, following ditch management and mink
(Neovison vison) control water voles colonised a
wetland nature reserve.
■■ Pochard (Aythya farina) populations on BBOWT
reserves has mirrored the national population
decline. Across 6 open water sites there has been a
drop in mean maximum count from 42 individuals
in 2005 to 4 individuals in 2015. Other species
such as tufted duck have remained relatively stable
(across 6 sites, mean individual max count in 2005
was 57, in 2015 it was 44).
Figure 4. Extent of water vole local key areas in Berks, Bucks and Oxon
21 J. Lawton, Making Space for Nature: A review of England’s Wildlife Sites and Ecological Network, 2010
22 The State of England’s Chalk Streams, WWF-UK, 2014
23 D.B. Hayhow et al., State of Nature 2016, The State of Nature Partnership, 2016
24 Fifth Otter Survey of England 2009 – 2010, Technical Report, Environment Agency, 2010.
25 M Eaton et al., Birds of Conservation Concern 4: The Population Status of Birds in the UK, Channel Islands and Isle of Man, British Birds 108, December 2015, p. 708–746
10
Calcareous grasslands
Conservation Status
Conservation Strategy
There is currently 30,687ha of chalk grassland in
England26. Chalk grassland develops on shallow limerich (pH range between 6.5 and 8.5) soils overlying
chalk. It is one of the richest habitats of Western Europe,
containing a great diversity of plants and animals,
many of which are nationally or internationally rare
or endangered. Chalk grassland may support over 50
species of flowering plant per square metre27.
The vast majority of chalk grassland was traditionally
managed as pasture and continuation of this traditional
management is essential in maintaining a floristically
diverse sward, in which coarse grasses are prevented
from dominating. This is primarily achieved through
late summer and autumn grazing using sheep or cattle.
Other vegetation including scrub is kept in balance by
hand control carried out by staff and volunteers.
Much of the flora found in these habitats are specially
adapted to the low nutrient, high pH conditions and
will simply not survive elsewhere. This specialism is
mirrored within the associated butterfly assemblage,
many species of which are dependent on key chalk
flowers and grasses as their caterpillars’ food plant, for
example small blue (Cupido minimus) and Adonis blue
(Polyommatus bellargus) butterflies.
Rare and threaten flora found on chalk grassland
include the Chiltern gentian (Gentianella germanica),
which grows only within the Chilterns in Great Britain
and monkey orchid (Orchis simia), both of which are
classified as Vulnerable28 in England. Between 1968 and
2006 pasque flower (Pulsatilla vulgaris) had disappeared
from 16 of its 33 known sites, with the losses being
largely due to inappropriate grazing management29.
BBOWT manages 130 hectares of calcareous grassland:
100% of which is classified as favourable or recovering.
Conservation Strategy
11
Conservation Impact
■■ Consistent grazing and scrub control help ensure
that chalk grassland sites remain floristically diverse.
One typical chalk grassland reserve has 34% cover
of rockrose (Helianthemum nummularium), 50%
cover of scabious species (Scabiosa columbaria
& Knautia arvensis) and 46% quaking grass (Briza
media); all of which are now classified as Near
Threatened, due to their decline in the ‘wider
countryside’.
■■ Silver-spotted skippers (Hesperia comma) are
expanding their range northwards in part due to
climate change. Management of chalk grassland
ensures the abundant short sward required by
this species is present, so promoting potential
colonisation by the occasional vagrants recorded
on sites. One site already supports a strong
population of this butterfly with a maximum count
of 19 individuals in 2014.
■■ Seven chalk grasslands support populations of
pure Chiltern gentian. Driven by the plant’s life
cycle requirements numbers vary significantly
between years. In any given year there can be over
10,000 individual plants. Following scrub removal
numbers have significantly increased at one of the
seven sites. Data is not available for years following
2013 as the population was too numerous to count
accurately (see figure 5).
Chiltern gentian
Figure 5. Chiltern gentian numbers at one chalk grassland nature reserve
26 Extent & Distribution of UK Lowland Grassland Habitats, Joint Nature Conservation Committee, jncc.defra.gov.uk/page-5848 (accessed 12 August
2016)
27 Meadows, Grass and Pasture: Introduction, Low Impact, www.lowimpact.org/lowimpact-topic/meadows-grass-pasture (accessed 12 August 2016)
28 P.A Stroh et al., A Vascular Plant Red List for England, Botanical Society of Britian and Ireland, Bristol, 2014.
29 K.J. Walker and C.E Pinches, Reduced Grazing and the Decline of Pulsatilla Vulgaris Mill. (Ranunculaceae) in England, UK, Biological Conservation,
144 2011, p. 3098–3105.
12
Fen, reedbed and wet grassland
This broad category draws together different habitat
types under the common requirement for the land
to be wet; or to put it another way, hydrology is a key
factor for habitat quality and sustainability.
Wet grassland in this context does not include haycut lowland meadow; but does cover wet grasslands
primarily managed for their wading bird and
invertebrate interest. The nesting sites of wading
birds including lapwing (Vanellus vanellus), redshank
(Tringa totanus) and curlew (Numenius arquata) are
wet grasslands with tussocky areas where fledging
chicks can shelter, and soft mud in which the adult
birds probe for their invertebrate food. Breeding by
the main wader species has been steadily declining in
the Upper Thames catchment, 43% since 200532. Taller
swards, particularly with species such as reed sweetgrass (Glyceria maxima) and greater tussock-sedge
(Carex paniculata) are the habitat of Desmoulin’s whorl
snail (Vertigo moulinsiana) – a rare European protected
species which has suffered declines and for which the
outlook is classed as “bad” 33.
Conservation Status
Fens occur where groundwater is at or around the land
surface all year round, maintaining wet conditions. Of
the estimated 3400km2 of fen present in England in
1637, only 10km2 remains today30. The water source for
a fen determines the plants and animals that make up
the wildlife present. All water ultimately comes from
rainfall; it is then fed into wetlands either from surface
flow or groundwater (soils or aquifers).
The water in fens fed from aquifers will have dissolved
minerals. The resulting vegetation communities
contain many species adapted to both the water
regime and the chemistry of the water. Base-rich fen
can be very floristically diverse, supporting a range of
specialist flora such as grass-of-Parnassus (Parnassia
palustris), black bog-rush (Schoenus nigricans) and
marsh helleborine (Epipactics palustris). The open water
found in the pools and streams on fen sites support
species such as common bladderwort (Utricularia
vulgaris) and a range of invertebrates including the
southern damselfly (Coenagrion mercurial) and the rare
calcareous fen specialist the clubbed general soldierfly
(Stratiomys chamaeleon).
BBOWT manages 92 hectares of fen, reedbed
and wet grassland: 99% of which is classified as
favourable or recovering.
Reedbeds are a type of fen, typically with very
high water levels and dominated by common reed
(Phragmites australis). Pure reedbeds often have very
low floral diversity, but do provide habitat for specialist
bird and invertebrate species such as bittern (Botaurus
stellaris), Cetti’s warbler (Cettia cetti), the scarlet tigermoth (Callimorpha dominula). Historically reedbeds
were widely distributed and covered large areas (e.g.
the Norfolk and Lincolnshire fenlands), but agricultural
management has reduced the current extent to around
6,500ha, with only around 15 sites being larger than
40ha31. The majority of sites are coastal, and sizeable
inland reedbeds in southern England are rare.
Fen at a nature reserve
13
Conservation Strategy
Conservation Impact
Fen and reedbed are semi-natural habitats, inasmuch
as they are not stable communities but mid-succession
habitats, and are maintained by human interventions
such as reed cutting (for thatching), peat digging or
grazing livestock. Copying traditional management
is required in the form of rotational reed and fen
cutting, low intensity grazing, and control over water
levels to be able to achieve the specific water regime
required by target species. Predator control may also
be required to safeguard the eggs and chicks of wading
birds. Targeted restoration of fen and reedbed habitat
is carried out to increase the habitat resource and link
extant patches. Scrape and ditch restoration in wet
grassland also benefits wading birds.
■■ Cutting dense sedge tussocks helps reduce its
competitive vigour. At one fen site this has resulted
in a significant increase in the number of early
marsh-orchid (Dactylorhiza incarnata), which has
risen from c.500 in 2009 to c.2300 in 2016.
Southern damselfly
■■ Across sites numbers of lapwing and curlew have
remained relatively stable between 2009 and 2015
(10 pairs and 11 pairs respectively), however total
numbers are low. This mirrors the national trend
of decline (50% since 197534). Management and
predation control measures are being implemented
to try and increase numbers of pairs breeding
successfully.
■■ Two calcareous fen sites support populations of
southern damselfly. The introduction of grazing
by Welsh ponies, ideally suited to the wetland
conditions, and increased vegetation cutting along
runnel edges has resulted in a significant positive
response in the southern damselfly population. In
2005 the maximum number of individuals recorded
was one; in 2015 the maximum count had increased
to 17 individuals.
Figure 6. Southern damselfly sightings at a
known local site
Southern damselfly
30 A. McBride et al. (ed), The Fen Management Handbook, Scottish Natural Heritage, Perth, 2011.
31 C. Hawke and P. José, Reedbed Management – for Commercial and Wildlife Interests. RSPB, Sandy, Beds, 1996.
32 C. Kinnear, Upper Thames Breeding Wader Report, RSPB, 2016 (unpublished)
33 Third Report by the United Kingdom under Article 17 on the implementation of the Directive from January 2007 to December 2012, Conservation status
assessment for Species: S1016 - Desmoulin’s whorl snail (Vertigo moulinsiana), Joint Nature Conservation Committee, 2013.
34 M. Eaton et al., Birds of Conservation Concern 4: The Population Status of Birds in the UK, Channel Islands and Isle of Man, British Birds 108, December 2015, p. 708–746
14
Hedgerows, farmland and rough grassland
Conservation Status
Hedges provide an important corridor for many wildlife
species, such as bats and dormice to travel across the
landscape. Many species of bird and insect also use
hedgerows as a primary habitat (to live in or on, rather
than simply travel through). The network of hedges at
Bernwood Meadows support a range of wildlife, but
of particular note are populations of black and brown
hairstreak butterflies. These butterflies have a restricted
distribution across the UK, particularly the black
hairstreak which is found only in the south and east
midlands. Since the 1970s the brown hairstreak has
experienced a 43% contraction in its range37, partly as a
result of intensive hedgerow flailing, which destroys the
new blackthorn growth the caterpillars depend upon.
8.9 million hectares (68%) of England is actively farmed
land35. Farmed land is an important habitat for native
wildlife. Birds, small mammals and invertebrates can
all thrive in agricultural systems. However, since the
Second World War farming practices have significantly
changed in response to domestic and global market
forces and advances in technology. This has resulted in
the decrease in the number of mixed farming systems;
the move from spring to autumn and winter sown
arable crops; the switch from hay to silage production;
increased mechanisation (contributing to hedgerow
loss) and increased pesticide and fertiliser use.
These changes have contributed to the loss of suitable
nesting and feeding habitats for farmland birds and
a general reduction in the availability of seed and
insect food, and a decrease in invertebrate biomass.
Between 1970 and 2013 the national populations of
corn bunting, tree sparrow, skylark and yellowhammer
declined by 91%, 90%, 62% and 54% respectively36.
We manage 10 hectares of hedgerows: 100% of which are in a
favourable or recovering state.
Rough grassland is very important for a range of
species, including small mammals, invertebrates and
raptors. The structure of the habitat provides safe cover
for small mammals, particularly harvest mice, to nest
and forage for food. Research has suggested that the
harvest mouse population declined by 71% between
1979 and 1997 due to changes in farming practices
across the UK38.
BBOWT manages 78 hectares of farmland: of which 99% is in a
favourable or recovering condition. We also advise numerous
farmers on practices that may promote wildlife.
BBOWT manages 57 hectares of rough and improved grassland,
of which 98% is in a favourable or recovering status.
15
Conservation Strategy
Conservation Impact
A wide range of measures to benefit farm wildlife are
in place on our agricultural holdings including in-field
skylark plots, beetle banks, margins sown with nectar
and pollen-rich species, uncropped headlands and
over-wintered stubbles to provide winter seed. These
measures are to specifically benefit seed and insecteating birds like corn bunting and skylark, but also have
benefits for pollinators, small mammals and overall
biodiversity.
■■ Creation of bespoke areas such as skylark plots and
arable margins within arable areas has benefited
farmland birds such as skylark (Alauda arvensis) and
corn bunting (Miliaria calandra). Arable populations
are stable with a mean 5 corn bunting territories
and a mean 8 skylark territories between 2010 and
2015.
Brown and black hairstreak caterpillars are entirely
limited to blackthorn, of specific, but different, ages.
Black hairstreaks require old, mature blackthorn
while brown hairstreaks need young, tender growth.
Management is therefore focused on ensuring that at
any given point in time there is sufficient blackthorn
at these different growth stages – coppicing and
laying are used to create the right balance. New
hedges containing a variety of native species have
been planted to benefit a range of birds and insects.
Blackthorn, common hawthorn and hazel are the
dominant species in the mixes, with other flowering
and fruiting shrubs included and oak and field maple,
these latter will be allowed to develop as standard trees
along the hedgerow. Tree sparrow boxes are put up in
suitable locations.
■■ One site with extensive rough grassland margins
supports a significant population of harvest mice
(Micromys minutus), with over 100 nests in 3 fields.
■■ The site also has a stable population of barn owl
(Tyto alba) (mean of 6 young fledged per annum
between 2005 and 2015); although this fluctuates
greatly in response to the weather.
■■ At least 8 sites support brown hairstreak (Thecla
betulae) populations. Rotational hedgerow
management is undertaken to provide the young
blackthorn growth required by the caterpillars. At
the sites with the largest populations, numbers are
currently stable.
Figure 7. Brown hairstreak eggs trend at one meadow site
Management of rough grassland is a careful balancing
act. Too frequent cutting or grazing will destroy the
tussocky grassland structure needed by the small
mammals, but too long a gap will result in scrub
invading and shading out the grassland altogether.
Currently, a mix of grazing and grass cutting with
the tractor is carried on a varied rotation to establish
which works best where to create the ideal structural
diversity. Any invading scrub which is too big to be cut
or grazed is removed by hand. In addition to the crucial
habitat management one site has six barn owl boxes.
These provide places for the owls to roost in, nest and
increase the population of this important farmland
bird.
35 Structure of the agricultural industry in England and the UK at June, DEFRA, www.gov.uk/government/statistical-data-sets/structure-of-the-agricultural-industry-in-england-and-the-uk-at-june (accessed 19 August 2016)
36 M. Eaton et al., Birds of Conservation Concern 4: The Population Status of Birds in the UK, Channel Islands and Isle of Man, British Birds 108, December 2015, p. 708–746
37 Brown Hairstreak, Butterfly Conservation, butterfly-conservation.org/50-1309/brown-hairstreak.html (accessed 22/8/16
38 UK Priority Species Pages, Joint Nature Conservation Committee, jncc.defra.gov.uk/_speciespages/2428.pdf (accessed 22 August 2016)
16
Conclusion
This Conservation Impact Report demonstrates
that conservation and enhancement of our natural
environment is possible. It also highlights that beyond
existing protected areas, such as our own nature
reserves, the pattern continues to be one of decline.
In fact across the UK, wildlife is in decline in all of the
habitats reviewed in this report.
central government can land managers deliver
enhanced biodiversity, alongside the provision of other
public goods such as flood relief and access to the
countryside.
BBOWT’s Conservation Impact Report coincided with
the publication of the State of Nature Report 2016,
produced by more than 50 conservation organisations,
including The Wildlife Trusts. This shows that more
than 10% of our species are threatened with extinction
within the UK. It also shows that the drivers of
decline are predominantly those associated with the
management of agricultural land.
BBOWT is able to show that when sites are managed
specifically for biodiversity, using best-practice
conservation techniques, key indicator species can be
maintained, and habitats can be restored and improved
for wildlife.
In particular, floodplain meadows in our region are of
major national importance. BBOWT is currently directly
responsible for over 10% of the national resource of
the UKs most wildlife-rich meadows. Our management
is protecting the sites that we are responsible for,
creating new habitats alongside existing meadows, and
supplying wild flower and grass seed for new meadows
beyond our nature reserves.
BBOWT takes the view that any effective strategy to
reverse the decline in wildlife in our region will have to
tackle the wider and largely agricultural landscape. The
decline of wildlife species on unprotected land will only
be halted when land managers improve habitats that
contribute to a network of wildlife-rich spaces between
the existing protected areas.
The management of protected areas, including our
own nature reserves, has also reduced the declines in
some key species. For example, conservation efforts
for nightjars and adders within protected areas, such as
Greenham Common, have had an impact on slowing
the loss of these key species. But protected areas only
cover a tiny proportion of our countryside.
Climate change is known to be a major threat to wildlife
internationally. Locally, the impact has been complex,
with some species able to take advantage of warmer
average temperatures, while others appear to have
declined as a result. For example, the hazel dormouse
appears to have been directly affected by the changing
climate, with warmer winters affecting hibernation.
If BBOWT and other conservation organisations are to
significantly reverse the declines in biodiversity across
the range of habitats covered in this Conservation
Impact Report, it is essential to have financial and
policy commitments from central government for
wildlife enhancement outside of existing protected
areas. Only when there is strategic support from
Acknowledgements
This report is based on data collected by hundreds of
volunteers and staff, during many thousands of surveys,
in over a decade of monitoring. Their continued
support and dedication has played a significant role in
enabling the understanding of the condition of nature
reserves and their value for biodiversity.
17
Photos: Kate Dent, Stacey Doran, Andy Fairbairn, Aubrey Jenkins,
Tom Marshall, Newbury Ringing Group, John O’Dwyer,
James Osmond, Alastair Rae, Helen Walsh, Colin Williams