IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Schnyder, J. | |
| Implications of the reintroduction of lynx (_Lynx lynx_) in Northeastern Switerland on the roe deer and chamois population and on the damage caused by game animals (Auswirkungen der Wiederansiedlung des Luchses (_Lynx lynx_) in der Nordostschweiz auf Reh (Capreolus capreolus) und Gamsbest„nde (_Rupicapra rupicapra_) sowie auf den Wildverbiss im Kanton St. Gallen) | |
| 2014 Full Book | |
In the context of the LUNO-Project (reintroduction of the Eurasian lynx in northeastern Switzer-land) the Eurasian lynx (_Lynx lynx_ L.) has been reintroduced to the canton of St. Gallen since 2001. A partial objective of this reintroduction was the reduction of the population size of roe deer (_Capreolus capreolus_ L.) and Alpine chamois (_Rupicapra rupicapra_ L.) and, in turn, a reduction of browsing intensities in young forest stands. This master thesis investigates the interactions between the levels of this tri-trophic cascade in the canton of St. Gallen. Data about lynx distribution, the development of browsing intensity as well as roe deer and chamois population-sizes (hunting statistics) were available. The results showed a significant reducing effect of lynx on roe deer population size. This effect, however, appeared to work cumulated with further factors like human hunting pressure and harsh climatic conditions. Furthermore, the analysis revealed a significant decline in chamois population size during the years after lynx reintroduction. This decline, however, could not be solely attributed to the lynx because there were several additional factors (for example diseases) involved which caused already years before lynx reintroduction a steady decline in chamois population. In addition, because the lynx prefers staying in the wood it is probable that it affected particularly these chamois which also prefer living there (and not high up in cliffs). Further analysis showed significant higher browsing intensities in areas with high local wildlife stock. But it appeared that the size of local wildlife stock is just one factor among many more, which influence local browsing intensities. Data about browsing intensity of a part of the study area showed a significant reduced browsing intensity of silver fir (_Abies alba_ MILL.) for years with lynx presence compared to years without. Large-scale analysis comparing browsing intensities of areas with different intensity of lynx presence suggested a reducing effect of lynx on browsing intensities, which, however, was statistically not significant. This master thesis gave an insight into the complex interactions between the levels of the tri-trophic cascade lynx-roe deer/chamois-populations and vegetation. However, facing dynamic spatio-temporal ecosystem processes the thesis deals only with a snapshot in time. It would be interesting to repeat this study at intervals of several years. Local habitat changes and the development of red deer (_Cervus elaphus_ L.) populations should then be considered too, as well as a homogenous ("lynx-free") reference area. Finally, this work also examined whether the partial objectives of the LUNO-project have been attained or not. An achievement of the objectives is evident, which has been confirmed by subjective impressions from local experts too. In addition, this study shows that - to investigate trophic cascades - it is recommendable to start a systematic data before the reintroduction of the predator, because before/after comparisons of data ensure more reliable results than the comparison of data of areas with different intensity of predator-presence. |
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