Mountain, hill and moorland

How

Management aimed at developing a range of habitats across an upland area will provide the greatest benefits to the largest variety of wildlife. A mosaic of the habitats described above alongside scattered native woodland, scrub and bracken, is likely to provide suitable conditions for a wider diversity of wildlife than an area solely consisting of grass or heather. Different habitats support different species, but they also work in combination. A good example is the curlew. They typically nest in tall vegetation or tussocks, the adults fly to feed on earthworms and leatherjackets in nearby pastures, but then travel with their flightless chicks to areas of damp ground to feed on aquatic invertebrates – the loss of any one of these habitats can lead to the loss of curlews from an area. A little time spent finding out about the range of wildlife using the land will help land managers take account of any rare or threatened species present.

Grazing and burning are the two main management tools used to manage these large upland expanses. Restoration of peatlands and wetlands damaged by historic drainage is also a priority.

Planning Grazing regimes

The agricultural stocking capacity of an upland area and the impacts that grazing has on its wildlife varies considerably depending on the proportion of different habitats present and the climate. The large scale of unenclosed uplands, and their typically low stocking rates, allows animals to preferentially graze individual plant species or vegetation types as their palatability and nutritional value changes through the seasons. Shepherding livestock can help utilise available forage more effectively and ensure overgrazing of favoured areas is avoided.

It is possible to enhance, (and conversely damage) individual upland habitats by changing stocking levels, grazing periods or type of grazing animal.

Stocking Levels

High grazing pressure over a prolonged period will reduce the abundance of certain plants, alter vegetation structure and in time change plant communities. Less palatable or unpalatable plants (e.g. mat-grass, wavy-hair grass, purple moorgrass) may come to dominate vegetation in such situations. Vegetation, soils and water features can all be damaged by trampling and potentially lead to erosion (increasing sediment flow in watercourses) and pollution. High stocking densities during the summer months can result in plants being unable to flower, reducing both pollen and nectar resources for a range of pollinating insects and seed production. High stocking will typically cause reduced height of vegetation, and increased uniformity of vegetation, both of which will negatively impact many upland species.

Very low or no grazing over an area will allow taller and denser vegetation to develop and herbs to flower and seed. If this is extended for a long period, it can allow dwarf-shrubs to increase in extent and, in time, pockets of scrub and woodland to form. This can create more varied structure and habitat mosaics that benefit a wider range of species, such as nesting habitat for merlins, black grouse and ring ouzels, and for adders and common lizards.

Suggested sustainable stocking rates vary between 0.05 LU/ha (livestock units per hectare) and 0.20 LU/ha, averaged across the year, which corresponds to approximately 0.3 – 1.3 breeding ewe per hectare, however this should just be used as a guide. Stocking levels should be set and modified in response to changes observed on the grazing unit such as vegetation height, extent of different habitat types or damage to plants such as heathers.

Grazing Period

Timing grazing to coincide with times when vegetation is at its most attractive to livestock will utilise grazing forage most effectively and will help to maintain a more diverse upland habitat. Livestock are attracted to areas of bent and fescue grasslands throughout the growing season, whereas areas of mat-grass are only palatable in early spring. Cottongrass, deergrass and purple moorgrass all offer better grazing during the first flush of spring growth.

Heather will be targeted either once other grazing areas have been diminished or in autumn/winter when the grasses stop growing. Younger heather, for example young shoots following burning, is generally more attractive than older heather. Avoiding heavy autumn and winter grazing will ensure sensitive plants such as ling heather (which will be damaged if more than 30% of its annual growth is removed) will be maintained in a healthy condition.

Grazing animal

Different types of livestock, including wild herbivores, have different impacts on vegetation both in the way they graze, access water and generally move around.

Sheep will avoid certain grasses (such as mat-grass, wavy-hair grass), and favour bent-fescue grasslands. They will browse on ling heather and other dwarf shrubs throughout the grazing season, but graze these plants more heavily, sometimes causing damage, in the autumn/winter.

Cattle are less selective graziers than sheep and will more readily consume mat-grass and purple moorgrass (particularly when it is young). Cattle do not readily graze heather, but can cause damage through trampling, and ‘pulling’ at plants. Due to their larger size and weight, cattle can cause damage to sensitive habitat features such as moss areas or wet spring heads. Cattle dung can provide a useful food for invertebrates which in turn will benefit many bird species.

Horses and ponies will graze low quality vegetation such as sedges and fibrous grasses more readily than sheep.

Deer will generally make more use of heather than either sheep or cattle but as they range over a much larger area are less likely to cause local overgrazing. Where deer are common it is important to consider the impact of deer on habitats in addition to that of livestock, and plan grazing levels accordingly.

Restoring moorland vegetation

Where heather has been damaged or suppressed through heavy grazing it can be restored by reducing grazing levels, in particular by removal of sheep in the autumn and winter months. Restoring heather on more grassy areas can be more difficult, but using summer cattle grazing to reduce grass competition can help open up areas for heather to re-establish.

Restoring hydrology

Many blanket bogs have been subjected to significant drainage works, where drains or grips were dug at regular intervals across vast areas. From both an agricultural and sporting perspective this drainage was not very successful and has increased problems such as water run-off and land erosion. It has also damaged important blanket bog habitats and reduced cover of Sphagnum mosses (which are the plants that form peat).

Wet moorland can be restored by blocking up these drains and re-wetting the peat by placing dams across the grips at regular intervals. This will help increase the cover of Sphagnum mosses, providing valuable habitat for insects which in turn provides feed for chicks.

Other moorland management practices

Supplementary feeding livestock because the land does not have enough available forage should generally be restricted to emergencies, such as periods of bad weather, as it can lead to soil enrichment and localised overgrazing of heather.

Burning and cutting can be used to break up uniform stands of heather to provide mosaics of vegetation of different heights which is important for birds while also helping livestock move around. It also allows younger, more nutritional heather to regenerate to provide food for grouse and sheep.

A burning plan should be developed to identify sensitive wildlife habitats and no burn areas. This should also aim to maintain heather of all ages, including areas of tall and over mature heather which can support a different range of plants, such as lichens and mosses. In some cases, such as on peat, burning will not be an appropriate management tool. Burning can be very damaging to reptiles – see further advice below.

In some areas moorland grasslands such as purple moorgrass swards are burnt to provide fresh young grass growth for livestock. This is generally not encouraged as over the long-term it can lead to dominance by competitive, fire resilient grasses.