Huftierbestände und Verbissintensitäten nach der Luchswiederansiedlung im Kanton St. Gallen

Abstract

In the context of the project "Lynx resettlement north-east Switzerland" (LUNO), the Eurasian lynx (Lynx lynx L.) was reintroduced in the canton of St. Gallen from 2001. As a consequence of reduced roe deer (Capreolus capreolus L.) and Alpine chamois (Rupicapra rupicapra L.) population sizes, one goal was the reduction of browsing intensities in young forest stands. This study investigates interactions between the levels of this trophic cascade by means of data on lynx distribution, roe deer and chamois populations (hunting statistics and population estimations) as well as browsing intensities. The results have shown significantly reduced roe deer and chamois population sizes in the years after lynx reintroduction. The effect of lynx could have worked cumulatively with factors like hunting, weather conditions and diseases (chamois). Within the chamois population, the lynx probably affected primarily the forest chamois, although before and after the lynx presence other causal reasons have been responsible for population decreases. Furthermore, there was noted a significantly positive relationship between hunting statistics (as an indicator of local ungulate population sizes) and browsing intensities, although the size of local ungulate populations was one influencing factor among many more. The browsing intensity of silver fir (Abies alba Mill.) was significantly reduced after lynx reintroduction in the core area of lynx distribution. All results have shown significant correlations and suggest an indirect influence of lynx on browsing intensities of silver fir. However, causal connections should be analysed in further studies.