In the context of the LUNO-Project (reintroduction of Eurasian lynx in northeastern Switzerland) the Eurasian lynx (Lynx lynx L.) has been reintroduced to the canton of St. Gallen since 2001. One aim of the project was a reduction of browsing-intensities in young forest stands in consequence of reduced roe deer (Capreolus capreolus L.) and Alpine chamois (Rupicapra rupicapra L.) population-sizes. This master thesis investigates the interactions between the levels of this tri-trophic-cascade. Data about lynx distribution, browsing-intensities as well as roe deer and chamois population-sizes were available. The results showed a significant reducing effect of lynx on roe deer population size which, however, appeared to work cumulated with further factors (hunting pressure, climatic conditions). The significant decline in chamois population-size could not be solely attributed to lynx because of the spatial behaviour of this species, several additional factors (e.g. diseases) and declining population-sizes already years before lynx reintroduction. Furthermore, Browsing-intensities were higher in areas with high local wildlife stocks, although the size of local wildlife-stock was just one influencing factor among many more. The browsing intensity of silver fir (Abies alba MILL.) has been significantly reduced after lynx reintroduction in a selected part of the study area. The comparison of areas with different intensity of lynx presence suggested reduced browsing-intensities in lynx presence areas which, however, was statistically not significant. The results have been confirmed by local experts subjectively. Facing the dynamic spatio-temporal ecosystem processes this thesis deals only with a snapshot in time. It would be interesting to repeat the study at intervals of several years. Local habitat changes, the development of the red deer (Cervus elaphus L.) population-size as well as a homogenous (“lynx-free”) reference area should then be considered too.