by Lois Mansfield
The Cumbrian fells represent one of the ecologically richest Upland habitats in England. These have been developed through subsistence farming over millennia, but during the last 100 years changes in our economy and government policy have started to take a toll on their unique flora and fauna. It is an area where potential conflict between nature conservation and agriculture can become contentious. New ways of working are being developed by the Government and local organisations to help redress this balance.
There are various types of upland habitat, which can be grouped into different categories: Montane; Woodland; Moorland (including Dwarf shrub heath, Grassland and Wetlands/Bogs/Mires) and Inland rock. Like all classification systems there are gradations between these types. The diagram below shows schematically how they relate to each other. Altitude, rainfall, temperature, and underlying morphology of rocks below play a significant part in determining which type of habitat will dominate.
Each habitat has its own particular fauna and flora. Many of these are currently threatened. The EU’s 1992 Habitats Directive on the Conservation of Natural Habitats and of Wild Fauna and Flora lists 42 different habitats that require designation as Special Areas of Conservation, of which 8 are uniquely found in upland environments. Within and around the Ullswater valley examples of all such habitats can be seen.
This is one of the harshest environments and the features of the flora and fauna reflect this – plants tend to lie flat on the ground to reduce frost and wind damage; two to six times as much biomass of the plant is below rather than above ground; and pollination is mainly by insects. Mosses are tolerant to snow.
In the low alpine level, between 900 and 600 metres, shrubs make their first appearance. There are three typical plant communities referred to as ‘mountain heath’: bilberry is the dominant vegetation. At the base of this level – 600 metres - is the tree line. Dwarf birch, montane willows, rock white beam and juniper are collectively known as ‘montane scrub’. These communities support a range of invertebrates.
Until the late 1700s montane birds such as the dotterel, and ptarmigan were present in the Lake District, but they are now restricted to the Scottish Highlands, following habitat deterioration from overgrazing, recreation and predation pressures. Buzzards are often seen soaring above the habitat, and the peregrine falcon nests above Hartsop. Habitat can be impacted negatively by grazing (deer and sheep), heather burning, as well as human recreational activities such as mountain biking and walking. Because of cold temperatures and limited growth, recovery can take some time. Willow and juniper can be particularly vulnerable since they are dioecious, requiring the presence of both male and female plants to reproduce. Maintaining montane vegetation is important for reducing the threat of soil erosion.
There are good examples of juniper on Patterdale Common below Place Fell, on Arnison Crag, and on the Glenridding screes.
There are very few areas of ‘original’ woodland left, between 600 and 250 metres. Deciduous birch, as well as native pinewoods and Scots pine are found on mainly acid soil. Ash and oak are found on neutral or alkaline soils. The Ullswater Valley is fortunate to host some truly ancient woodland, notably in Glenamara Park at the southern end of the lake where 400 year old sessile oaks and wizened birches can be found. These are habitats that attract spotted flycatchers, greater spotted woodpeckers, red squirrels, and roe deer.
Hallinhag wood on the south eastern shore of Ullswater is a natural oak woodland, with other species such as rowan, beech and Scots pine. The understory is carpeted in mosses, lichens, ferns, wood sorrel and wood sage, with bryophytes and honeysuckle draping the upper layers of the trees. It’s a magical place. The diverse microhabitats in the tree trunks provide ideal habitats for many woodland birds: great and blue tits, tree creepers, pied flycatchers and woodpeckers, all nest in the wood.
Upland woodlands provide shelter for deer, sheep and cattle. Grazing of the understory vegetation can however be problematic. In former times, many species were pollarded (limbs pruned to about 2 metres above ground level) or coppiced (cut back at ground level), but between the 1890s and 1950s these practices have been reduced with the effect that the trees are even-aged, structurally less diverse and subject to toppling in high winds.
Woodlands have traditionally been managed for a variety of uses: charcoal production for iron and lead smelting and use in lime kilns, fencing, and production of timber for building. Examples of such uses are found throughout the valley. Such has been the pressure on woodlands that some forests marked on the OS map no longer exist – at Grisedale Forest near Ruthwaite there is not a tree in sight.
This archetypical upland habitat is a mosaic of three different habitats: dwarf shrub heath, grassland and wetlands/bogs/mires.
Dwarf Shrub Heath
The dominant species are ling, cross-leaved heath and bell heather. These live often in association with bilberry, cowberry and bearberry. The diversity of the invertebrate fauna is often surprisingly high, with many species of carabid beetles, and spiders. Golden plovers, ring ouzels and curlews favour this type of habitat, as well as rabbits. The soil tends to be peaty, with a low mineral content.
Grazing by sheep, burning to provoke regeneration, and other management methods have been applied to promote increased productivity. De-stocking can produce growth of bracken and gorse, which brings its own challenges. An innovative technique to produce peat-free compost from a mixture of bracken and wool is being tried at the northern part of the lake between the slopes of Heughscar hill and Askham fell.
Upland grassland is either enclosed – in the form of ‘inbye’ and ‘intake’ for sheep and cattle grazing, or unenclosed. There are examples throughout the Valley of a whole range of management regimes that have been applied over the years to improve the palatability and productivity of grasslands for fodder. This may involve leaving the grass for direct grazing; ‘improving’ the grass with fertilisers or muck spreading, or leaving it as natural meadow for hay. The quality of the grass will vary according to drainage, the underlying minerals, temperature and other factors. In the Ullswater Valley both acid and alkaline (underlying limestone) grasslands are found.
The diversity of the flora and fauna of these areas is intimately linked with the way in which the land is managed. The presence of skylarks, of particular types of butterflies: fritillaries, argus, mountain ringlet, and small blue all tell their own story on the history of land use. Corncrakes used to be widespread in Cumbria but are now very rare. Trampling of grass by cattle and sheep has been shown to have a significant impact on species diversity. This can impact soil quality and the microfauna within the soil in surprising ways when stocking rates are exceeded.
Walkers will be very familiar with these types of habitat! They vary significantly – some being more permanent than others. The areas around Sheffield Pike, Birkhouse Moor, Birks, Angle tarn and Beda fell are all subject to waterlogging at different times of the year. Sphagnum mosses are common, as well as sedges, cotton grass, butterworts, and insectivorous sundews.
Such habitats need an annual precipitation over 1200 millimetres, at least 160 wet days per year, and an annual mean temperature of no more than 15 degrees C.
In certain valleys, such as Grisedale, the zig-zag tracks of sledges used to bring down peat harvested from Birks’ fell sides are still visible, although peat cutting has stopped a long time ago.
Some areas of the valley have suffered from drainage and block planting of conifers and other species. But increasingly, more sensitive forestry management practices are being applied, using multi-species mixes and blending plantations with the landscape.
Inland rock: This category includes ledges, crags, scree slopes, and limestone pavements. The plants, lichens, mosses and invertebrates inhabiting these specialised places can often withstand extremely infertile conditions. They also avoid competition from more vigorous plant species, and can avoid the pressure of grazing animals.
The species that colonise such places are highly specialised, potentially vulnerable and rare. The John Muir Trust is currently engaged in a programme to restore some of these communities on Helvellyn, by breeding and planting purple saxifrage, water avens, alpine cinquefoil, and downy willow.
The Government has introduced various measures to ensure sheep are not allowed to graze these areas at certain times of the year. Winter climbers must follow strict guidelines to avoid disturbing plants that hang on to narrow crevices.
An increasing number of Government-financed schemes are now in place to ensure a proper balance between the conservation of Upland habitats and their management for farming. If farmers are to embrace successful low-input/low-output systems that helped to create the multiplicity of Upland ecological habitats, they need to be presented with options that ensure farm businesses are economically viable. There are also opportunities to improve peatland wetlands restoration for carbon sequestration to mitigate the effects of climate change.
The Cumbrian Fells of Ullswater are classified as 10+ (Outstanding) in terms of England’s Habitat Diversity status. Care is needed to ensure this rating is maintained.
by Professor Lois Mansfield