SAC Research

The overall aims of the project were:

• To monitor the impact of changed grazing management on a range of key NATURA 2000 habitats on the Cam Chreag (part of the Ben Heasgarnich SAC).
  
• To promote the development of montane willow scrub within the Ben Heasgarnich SAC, by the introduction of new plant material and through the positive management of the existing habitat.

The management objectives of the project were:

• To avoid deterioration of the key NATURA 2000 habitats – species-rich Nardus stricta grassland (CG10 and CG11), alpine pioneer formations of Caricion bicoloris-atrofuscae (M10 and M11), and alpine calcareous grasslands (CG12 and CG14), plus their associated rare plant and invertebrate species by implementing an appropriate monitoring programme and livestock grazing regime.
  
• To avoid deterioration of the montane willow scrub, eutrophic tall-herb and chasmophytic vegetation by implementing an appropriate livestock grazing regime and monitoring programme.
  
• To maintain, and where necessary, improve the condition and extent of the montane willow scrub, eutrophic tall-herb and chasmophytic vegetation and their associated rare plant and invertebrate species by erecting sheep exclosures and by introducing new plant material derived from plants already on site.

Approach & Measurements:

1. NVC quadrat survey of the Cam Chreag (42 random quadrats)

2. NVC vegetation map of the Cam Chreag

3. Condition survey and grazing impact assessment

4. Quadrat monitoring (re-survey of quadrats initially surveyed in 1985)

5. Monitoring of the grazed sward surface height

6. Monitoring of the vegetation within the fenced enclosures (quadrats and sward surface heights)

7. Monitoring of tall herb vegetation

8. Monitoring of nationally scarce species

9. The propagation, planting and monitoring of Salix arbuscula on the Cam Chreag

10. Mountain Ringlet (Erebia epiphron) monitoring

1. Grazing is necessary in order to maintain the species-rich grasslands. The removal of grazing rapidly leads to changes in the structure and species composition of the sward. A number of low growing herbaceous species, including some scarce montane plants, declined following the removal of grazing. There was an increase in the frequency of some of the tall herb species following the removal of grazing, but few of the tall-herbs flowered and many remained short in stature. The conservation value of the Cam Chreag would be considerably reduced if sheep were removed entirely from the site.

2. The condition of the alpine calcareous grasslands was maintained following the change from all-year-round grazing to spring-to-autumn grazing. However, the sward height of the vegetation increased and is above the ‘favourable condition’ target height. In the short-term, off-wintering did not result in an increase in the height or flowering of the monitored tall-herb or scarce species.

3. The propagation and planting of Salix arbuscula appears to have been successful. Most of the plants have survived and grown, however growth rates have been slow and it will be a number of years before they become fully established.

4. Fenced exclosures are necessary in order to both promote the development of montane willow scrub and to maintain the short, grazed species-rich grassland. The size and location of any exclosures needs to be carefully considered and a value judgement has to be made between the loss of species-rich grassland that will occur compared with the gain in willow scrub and tall-herb vegetation.