Abstract: Sheep grazing in the Norwegian mountain ecosystems has been described as the prerequisite for a high productivity and species richness or, alternatively, as the cause of degradation of grazing resources and subsequent reduction in populations of smaller herbivores. The present project aims for a better understanding of the significance of different nutrient availability and grazing pressure on the ecological effects of the grazing. We used transect sampling for soil properties, vegetation, insects, passerine birds, rodents and faeces from sheep, hare and ptarmigan. In addition, habitat use by sheep and (in other areas) by domestic reindeer was studied with GPS Telemetry. We found a positive relationship between soil nutrients, palatable plants, species richness of insects and densities of passerine birds, rodents and faeces from sheep and hare. Intense sheep grazing in resource rich areas was related to an increase in plant traits for low palatability. We found a profound difference in grazing pattern between sheep and reindeer, in that sheep grazed intensely in preferred patches leaving adjacent areas untouched whereas reindeer grazed more evenly while moving over large areas.
The project is further described in:
- Skarpe, C., Dhillion, S., Gjershaug, J-O., Halley, D.J., Nygård, T, Pedersen, H-C., Rusch, G. & Ødegård, F. 2005. Sau og fjelløkosystemet. In: Jonsson, B. & Yoccoz, N. (eds.) Økosystemdynamikk: menneskelig påvirkning på biologisk mangfold. NINA Temahefter 33.
- Rusch, G.M., Nygård, T., Spörndli, C., Gjershaug, J-O. & Skarpe, C. 2003. Fjellet og sauen – og samspillet. Villreinen 2003:104-111.
Latest news: Solveig Angell-Petersen (NTNU) wrote her MSc thesis “Ungulates and biodiversity in Norwegian mountains: effects on other mammals and selected birds” 2008 on the comparison between areas grazed by sheep- and by reindeer
Sheep in the Forolhogna mountains (photo Solveig Angell-Petersen)