Lowland wetlands - North York Moors National Park

North York Moors National Park
Lowland Wetland Habitat Action Plan
2008– 2012
North York Moors National Park Authority
Lowland wetlands
Habitat action plan
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Lowland Wetlands
North York Moors National Park
Lowland Wetland Habitat Action Plan
2008–2012
Objectives
1. To maintain the quality and extent of lowland wetlands in favourable conservation
condition, according to Natural England criteria.
2. To improve the ecological quality of degraded lowland wetlands.
Introduction
Diverse lowland wetlands are among the most productive UK habitats and can
support one of the most varied floral assemblages of all UK habitats. They support a
vast and varied invertebrate biomass which in turn supports many breeding birds,
notably waders and their chicks. Water voles, water shrews, otters and a variety of
bats species are among the mammals that depend on good wetland habitat.
The UK Biodiversity Action Plan priority habitats included in this plan are set out
below. Some flush and swamp habitats may also be included, although those found
at an elevation above enclosed farmland in the North York Moors are included in the
Moorland Habitat Action Plan.
• Lowland fen
Fens are areas of wetland, often overlying peat, that are fed by groundwater
as well as rainfall. Calcium-rich fen habitats are often very diverse botanically,
and may contain rare plants such as globeflower and bird’s-eye primrose.
They are often found in close association with flushes and springs. Fens in
the National Park are exceptionally important for their invertebrates, including
Eubria palustris, Vertgio geyeri, and a wide range of rare Diptera.
• Reedbeds
These are marshes dominated by the common reed Phragmites australis,
where the water level remains above or at ground level all year. They contain
few plant species, but contain a huge biomass of plant and invertebrate
material, which in part explains why they are considered one of the most
important UK habitats for birds.
• Floodplain grazing marsh
Grazing marshes are grasslands found on the floodplains of rivers, or in lowlying
coastal zones that are known to flood at least once every 100 years. The
best examples have high water levels, maintained by ditches rich in flora and
fauna. Most have been improved for agricultural use by adding fertilisers;
however, their wet nature makes them particularly valuable for breeding
waders and wintering wildfowl.
• Species-poor examples of purple moor grass and rush pasture
Lowland purple moor grass Molinia caerulea and rush pastures are found on
poorly drained soils in lowland areas with high rainfall. They are usually
situated on undulating plateaux and hillsides, as well as in stream and valley
mires.
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North York Moors National Park
Lowland Wetland Habitat Action Plan
2008–2012
National status
Wetlands can be found in most parts of Britain, but intensive drainage for agriculture
has greatly reduced their size and extent. Where they remain, it is only as isolated
pockets of habitat which are often degraded as a result of intensive agriculture.
The UK has about 56,000 ha of purple moor grass and rush pasture habitat, mostly
concentrated in Scotland and Wales. There are about 5000ha of reedbeds remaining
nationally, although of the 900 or so sites contributing to this total only 50 are greater
than 20ha, and larger sites are mainly concentrated in the south-east of England.
There is thought to be over 200,000ha of floodplain grazing marsh in England, but
only 5000ha is deemed of good quality.
Local status
Wetlands have followed the national pattern of decline, largely because of
intensification of farming. The small size and isolated nature of many of the patches
of marsh and fen left within the National Park make these habitats particularly
vulnerable to further degradation.
Very little detail is available on the extent of wetland habitats within the Park. This is
largely because the majority of sites form part of an intricate mosaic with other
grassland, heathland and woodland habitats. Many potentially important sites have
not been formally surveyed. Current knowledge suggests that there are only two sites
remaining with extensive reedbeds, totalling 13ha. The Park’s most important
lowland fens and purple moor grass and rush pastures are mostly found in and
around forestry, where agricultural land management has been restricted. Forestry
areas are particularly rich in calcareous fen with several important tufa-forming
springs scattered within the Dalby Forest area.
Many of the Park’s fen communities, such as M13 Schoenus nigricans mires, M22
Juncus subnodulosus fen-meadows and Cirsio-Molinietum fen-meadows, are of
national significance as they are at the edge of their geographical range.
Legal status
There are 18 ha of SSSI fen within the park, and many other designated sites contain
some element of lowland wetland. Sites without designation have no specific
protection from agricultural improvement.
Links to other action plans
Habitat Action Plans: Species Action Plans:
Rivers and Streams*# Water vole*#
Species rich grasslands Bats*#
Farmlands Farmland birds*#
Great crested newts*#
Common toad*#
Small pearl bordered fritillary*#
* = Local Species Action Plan Orchids*#
# = UK Species Action Plan(s) Geyers whorl snail#
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Threats
North York Moors National Park
Lowland Wetland Habitat Action Plan
2008–2012
Odontomyia hydroleon#
• Drainage to improve the value of land for agriculture has been the major
cause of decline in lowland wetland habitats in the National Park.
• Valley fens are particularly susceptible to pollution. Eutrophication from
fertiliser run-off leads to increased plant growth and reduced species
diversity. Trapped silt can dry out wet habitats, and toxins from agricultural
chemicals can kill associated wildlife.
• Many wetland sites are no longer being actively managed through grazing or
cutting and many of these are showing an increase in coarse vegetation and
encroachment by willow and alder scrub.
• Lowland wetlands are not currently seen as a valuable agricultural resource
and payments for maintaining them under agri-environment schemes often do
not reflect their importance to wildlife or the cost of their management to the
farmer.
• There is a lack of up-to-date knowledge concerning the distribution and
condition of lowland wetlands in the National Park, so valuable sites can be
inadvertently lost.
• Lowland wetland habitats cover a small total area in the National Park and
have a highly fragmented distribution. Associated populations of plants and
animals are vulnerable to local extinction because of their small size and the
lack of connectivity.
Requirements
• Inappropriate drainage systems can be deliberately broken up to allow
flushes and marshy grassland areas to redevelop.
• Sensitive livestock grazing and/or cutting regimes are needed to keep
invasive species and scrub at bay whilst breaking up, but not poaching, the
soils and allowing the majority of plants to set seed in at least one year in
three. Cattle and ponies may be particularly useful for this task.
• Continuity of low-input management should be maintained, with the
application of no inorganic fertiliser, no manure and no herbicides.
• Invasive weeds such as creeping thistle and bracken may need to be topped,
trampled, weed-wiped or spot-sprayed to prevent their spread.
• Scrub should be managed to prevent it encroaching on wetland areas. Where
wet woodland is an important component of the habitat, a diverse scrub edge
zone should be encouraged.
• Leave wide arable margins as buffer strips to adjacent wetlands.
• Funding is needed for wetland restoration tasks to be carried out and to
ensure the conservation management of a wetland network.
• Further survey work is needed to identify wetland areas within the national
park.
Current Local Action
• In agri-environment schemes, such as Countryside Stewardship,
Environmental Stewardship or National Park schemes, land managers agree
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North York Moors National Park
Lowland Wetland Habitat Action Plan
2008–2012
to maintain wetlands. Money is also available in severe flooding areas for
creating wetlands, usually through the blocking of land drains.
• Biodiversity leaflets have been distributed to all farmers in the National Park,
enabling them to identify wetlands on their land, describing how management
can maintain or enhance the resource, and outlining ways money can be
obtained for carrying out work through agri-environment schemes.
Opportunities
• There is potential for extending the wetland area within the park through the
restoration of former wetland zones. This work could be used to help alleviate
flooding and to allow for the movement and spread of wetland species.
• Re-visit all species-rich lowland wetlands identified in either the 1987 Phase 1
Habitat Survey, the 1991–1993 Phase 2 Survey or subsequently.
What you can do to help
Land managers:
• Implement the list of habitat requirements above.
• Liaise with the National Park over conservation land management.
Public:
• Assist the North York Moors National Park Volunteers with lowland wetland
management. Phone the Volunteers Service on 01439 770657 for details.
• Report flower-rich wetlands and rare plants to the National Park using the
online recording form on the National Park’s website:
www.moors.uk.net/recording
• Leave all wild flowers for others to enjoy.
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