Download Managing change in the uplands

Managing change in the uplands
Mariecia Fraser
I nt ro d u c t i o n
Land with Less Favoured Area (LFA) status accounts for around
45% of the agricultural area of the UK, while for Wales this
percentage rises to almost 80%. The traditional basis for farming
these LFA areas is the raising of sheep and beef cattle, with the
UK hills and uplands carrying around 12 million breeding ewes
and more than a million suckler cows,in each case just over 60%
of the UK total. Incomes on hill farms have always been low,with
producers heavily reliant on government support and subsidies.
In the decades following the Second World War, great efforts
were made to improve agricultural productivity in the uplands.
Large areas of hill land were set to the plough, and new swards
of cultivated grasses specifically bred to cope with marginal
conditions were established. Improved permanent pasture and
temporary grass leys account for around one-third of the grazed
areas of the hills and uplands today. Crucially, herbage
production from these improved swards can be over five times
higher than that from the indigenous grasslands and,
consequently, such pastures are vital to the viability of livestock
farming in the hills. The remaining two-thirds of UK grazed
uplands which remain unimproved include some of the
country’s most stunning and evocative landscapes. However,
these rugged and diverse spaces, so valued for their aesthetic
and amenity value, are also the product of man’s intervention,
and while they contain habitats that are recognised as having
international importance from a nature conservation
perspective, there has been a significant decline in both the
condition and extent of many of these ecosystems as a result
of inappropriate management.
Figure 2.1: Heather moorland, an upland community with
international conservation significance.
Prior to reform of the Common Agricultural Policy (CAP) in 2003,
support for livestock farming in the LFAs was based on headage
payments. This encouraged overstocking, which not only
resulted in overproduction of livestock but also the overgrazing
of fragile grassland environments. The oversupply of upland
sheep and cattle had a negative impact on the development
and availability of the high quality livestock needed to restore
UK and export markets, while the overgrazing led to ecological
imbalance and environmental deterioration. In particular, heavy
grazing by sheep has been linked to a reduction in heather
(Calluna vulgaris) and other dwarf shrub species, and their
replacement by the invasive grasses Molinia caerulea and
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Nardus stricta. The loss of key plant species from these
ecosystems impacts upon their habitat value, which, in turn,
has implications for internationally important insect and bird
populations. Innovative management strategies that deliver
both economically and environmentally sustainable upland
systems, being multi-functional in terms of farming, rural
development and the environment, are therefore urgently
required. While the policy drivers for the hills and uplands may
have changed substantially over the course of the last half
century,the requirement for sound scientific evidence on which
to base new policies is consequently as great now as it has ever
been.
The role of the grazing animal
Critical to the development and refinement of management
guidelines for such areas is an improved understanding of
plant/animal interactions within grazed ecosystems, and
recently our research has focused on quantifying the economic
and environmental impacts of alternative grazing options. There
is evidence from studies of both wild and domestic herbivores
that variations in grazing habits exist between different livestock
species. In general, larger animals with higher body weights
have a greater requirement for nutrients in order to maintain
body function and support growth and production. Crucially,
this increase is not linear and, consequently, a larger grazing
animal will have less time to spend selectively foraging for food,
per unit of nutrition consumed, than a smaller animal. As a
result, cattle are generally less selective in their feeding than
sheep and will tend to focus their grazing on taller,less digestible
patches of vegetation in order to maximise their intake.
Furthermore, cattle are more likely to need to move to more
accessible parts of the sward or to graze other communities
once preferred areas have been grazed too closely to allow
intakes to be maintained. Extending this hypothesis,
experimental work has shown that periods of grazing by cattle
can be beneficial in terms of controlling invasive hill species such
as Molinia and Nardus.
Studies investigating the foraging behaviour of free-ranging
herbivores grazing complex swards have demonstrated that
differences in selectivity can lead to niche separation between
animal species, and hence give opportunities for
complementary pasture use. Thus, the presence of one species
can be beneficial to the productivity of other species in
particular areas. Previous experiments with sheep and beef
steers grazing permanent pasture have shown that both mixed
and sequential grazing systems have the potential to deliver
improved sheep performance without compromising cattle
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productivity,leading to a higher total output per unit area. These
benefits appear to arise from a combination of different
preferences for plant species and parts, a reduction in sward
rejection due to dung contamination, and a lower intestinal
parasite burden. These findings demonstrate that, through
changes to grazing management, it is possible to increase
productivity without increasing inputs, thereby improving both
economic and environmental sustainability. This work is now
being extended to suckler-based beef systems, as the grazing
behaviour of mature cows is known to be different to that of
growing stock. On-going work is also clarifying the effect of
adjusting the cattle to sheep ratio within mixed grazing systems,
since national statistics reveal that there is considerable regional
variation in the ratios of these two species. There is potential to
extend this species comparison work to assess the impact of
alternative livestock species and to explore the associated
opportunities. In Wales, there is particular interest in
understanding the potential role of hill ponies as grazing
management ‘tools’. There is also an urgent requirement
for improved knowledge of the ways in which interactions
between animal species, diet selection and plant chemistry
influence diffuse pollution from grazing systems, in order to
deliver the biodiversity benefits of grazing while minimising
nutrient losses to soil, water and air.
Exploring breed differences
In recent times, there has been a growing number of schemes
encouraging the use of ‘rare’ or ‘at risk’ breeds as conservation
grazers. While evidence in support of claims that grazing by
these animals is beneficial in terms of improving biodiversity is
largely anecdotal, it remains possible that differences in body
size could give rise to breed differences in feeding behaviour.
To explore this issue further,a series of grazing experiments with
continental-cross and traditional beef steers investigated
genotype x environment interactions when grazing improved
permanent pasture and Molinia-dominated rough grazing.
These studies established that utilisation of Molinia caerulea by
the continental-cross and traditional breed steers was broadly
similar. Performance results indicate that, while genotype may
influence the liveweight gain of younger calves, breed type has
little impact on the performance of older steers. In contrast, the
type of sward grazed was found to have a highly significant
effect on growth rates regardless of age (Figure 2.2). Likewise,
while breed was found to have comparatively little effect on
meat colour or stability, pasture type had highly significant
effects on both. Pasture type also had greater impact on the
fatty acid composition of the meat, but there was no effect on
meat flavour.
Figure 2.2: Effect of pasture type and genotype on the
growth of finishing steers.
More recently, detailed preference experiments with different
breeds of sheep and cattle grazing heather moorland have been
conducted. The results highlight the substantial difference in
diet composition between cattle and sheep when grazing this
type of vegetation (Figure.2.3) and suggest that sheep exhibit a
greater degree of individual variation in grazing behaviour.
Significant differences were identified in the proportions of key
plant groups consumed by the two sheep breeds, with the
Scottish Blackface diet containing a greater proportion of
heather. These results demonstrate that important differences
in forage selection exist between commercial breeds of hill
sheep, and imply that there is potential for specific
environmental goals to be met more effectively without
compromising returns from conventional production systems.
Given the wide regional variation in hill and upland sheep
breeds across the UK,there is a pressing need for this work to be
extended. Information on the comparative grazing behaviour of
crossbred and composite sheep breeds is also required, given
recent predicted changes to the structure of the sheep industry.
Although the forage selected and consumed by the two breeds
of sheep were different, the diets selected by the modern and
traditional breeds of suckler cow were found to be broadly
similar. These findings,along with those from the Molinia studies
outlined above, imply that commercial breeds of cattle could
potentially deliver many of the environmental benefits of
grazing currently associated with traditional breeds. However,
the continental cattle failed to thrive at exposed, high altitude
sites. Thus, although the impact on the vegetation of such
animals would be similar, there are likely to be production, and
possibly welfare, implications associated with using this type of
stock in very marginal areas. On-going research is determining
the economic and environmental impacts of grazing options
which integrate different sward types, and the longer-term
performance of suckler systems based on Limousin-cross and
Belted Galloway cattle.
Figure 2.3: Principal component analysis of faecal concentrations of n-alkanes and
long-chain fatty alcohols sampled in September from animals grazing heathland
with 60% cover of Calluna vulgaris.
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New challenges
Looking to the future, climate change will impose further
demands on upland systems. It has already brought greater
awareness of the role the uplands play in providing ‘ecosystem
services’ which help maintain a well-balanced, regulated
environment. This has raised questions with regards to how to
define ‘public goods’, how to pay for them, and how to balance
these public goods with the need for food production.
Uplands provide 70% of the UK’s water supply, and
management in these areas strongly influences water quality.
Predicted changes to rainfall pattern will lead to upland areas
playing an even greaterrole in water management and flood
control for low-lying areas downstream. At the same time,
temperature rises are predicted to be greater at higher altitudes,
and this, together with a reduction in summer rainfall, will
increase the risk of summer drought and wildfires in hill and
upland areas. However, such temperature changes and an
associated lengthening of the growing season could enable the
uplands to become agriculturally more productive. Such
changes may lead to the adoption of new crops and livestock
breeds in the uplands, potentially compensating for a loss of
food production in lowland areas associated with the growing
of bioenergy crops. The uplands could therefore play a crucial
role in ensuring food security, but this capacity is as yet largely
undefined and untested. There is also a pressing need for more
information regarding the effect of agricultural land
abandonment in the hills and uplands, notably on landscape,
ecosystems, water retention, carbon balances and biodiversity.
With so many policies and support schemes relating to the
uplands currently under review, perhaps the greatest challenge
of all will be agreeing an evidence-based vision for these areas
and developing an integrated framework for delivery.
Mariecia Fraser
email: [email protected]
Figure 2.4: Belted Galloway cattle grazing Molinia-dominated
rough grazing at Bronydd Mawr.
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