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Unsustainable grazing impacts

On our moorlands and in our woodlands, domesticated and wild herbivores, including sheep, cattle, deer and feral goats are widespread. As well as being central to the land management economy, they are also part of the National Park’s cultural and natural heritage. Unsustainable levels of wild and domesticated grazing animals in upland and woodland areas can however lead to loss of species in the ground flora, simplified woodland structure without shrubs or climbing species, reduced tree cover and the erosion of soils, which are important carbon stores.

The condition of habitats outside of upland Designated Sites is largely unknown and SNH has been working with Deer Management Groups to collect data to assess the level of herbivore impacts on habitats, such as dwarf shrub heath and blanket bog.

There are 37 out of a total of 67 sites (some of them overlapping, i.e. SSSIs and SACs) where the designated features are under pressure from over grazing. But there are also five sites where designated features are under-grazed proving that this is a complex issue that needs careful collaborative management.

The Native Woodland Survey of Scotland (NWSS) published in 2014 identified the level of herbivore impacts within native woodlands. A low or medium level of herbivore impact is natural and required for sustainable woodland ecosystems and a low level of impact indicates natural regeneration is unlikely to be inhibited by herbivores and in general this is the ideal level of optimum long-term woodland condition.

Within the National Park there are 5,787 ha (NWSS 2014) of native woodland of which 5,063 ha has some herbivore impacts recorded. In the table below, the level of impacts recorded in the National Park is compared with the national (Scottish) average.

Herbivore Impact Category National Park Scotland
Low 3% 14%
Medium 60% 53%
High 17% 13%
Very High 21% 20%


A sustainable woodland ecosystem requires herbivore impacts to be in the low and medium categories; the national average is 67% in these two categories. The woodlands within in the National Park fall below this average at 63% demonstrating a higher level of unsustainable grazing compared to the national level.

Objectives by 2023

  • Work with Deer Management Groups to gain a greater understanding of the wild herbivore grazing pressures throughout the National Park.
  • Increase the number of land managers involved in habitat impact assessments and use this data to inform management decisions.
  • Decrease the number of designated sites with the pressure recorded as over-grazing from wild or domesticated herbivores, to be monitored via Herbivore Impact Assessments (Site Condition Monitoring) in future.
  • Decrease the percentage of native woodlands with High or Very High NWSS Herbivore Impact categories.
  • Improve upland and woodland condition by supporting rural businesses to achieve viable and sustainable grazing livestock levels through targeted land management advice and support in accessing the Scottish Rural Development Programme or equivalent.
  • Improve knowledge exchange with land managers, highlighting the damage that over-grazing can do to habitats, so that land managers know why they are being asked to do particular management.
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