Einfluss wildlebender Huftiere auf die Waldverjüngung: ein Überblick für die Schweiz

Influence of wild ungulates on forest regeneration: overview for Switzerland Terminal shoots of tree saplings are part of the diet of chamois, roe and red deer, which in turn can affect forest regeneration. We investigated the current extent of browsing influence on the Swiss forest and the existence of regional differences. Our overview includes all available, regionally assessed data on the influence of roe deer, chamois and red deer in Switzerland, i.e. data of the fourth Swiss National Forest Inventory (NFI 2009/13) and data from the cantons derived from 1) representative sample plot inventories, 2) surveys in selected forest areas and 3) assessments by expert opinion. In the time period between approx. 2009 and 2014 no larger region of Switzerland stood out with respect to browsing influence. On the level of the ungulates home range or forest districts we found large differences in the browsing impact, but on at least two-thirds of the assessed forest area of Switzerland browsing had no major influence on single tree species nor on forest regeneration in general (browsing level 1). In the colline vegetation belt frequent browsing has the most adverse influence on oak, in the montane belt on silver fir and in the lower subalpine belt on maple and rowan. Investigations focusing on a better understanding of the relationship between the objectively measurable browsing intensity and regeneration density as well as data on seedlings <10 cm would allow an even better assessment of the browsing influence on the forest. With Swiss-wide standardized assessments by expert opinion within uniformly defined ungulate home ranges, the comparability of data on the impact of wild ungulates on the Swiss forest could be further improved.