Impact of ungulates on structure and dynamics of natural regeneration of mixed mountain forests in the Bavarian Alps

For about the last 20 years, investigations have been carried out to determine the influence of various ecological factors on the natural regeneration of a mixed mountain forest (Picea abies (L.) Karst, Abies alba Mill., Fagus sylvatica L., Acer pseudoplatanus L.) in the Bavarian Alps. One of these factors is the influence of a ungulate population involving three species (Capreolus capreolus (L.), Cervus elaphus L., Rupicarpa rupicarpa (L.)). Investigation results show that ungulates play a very important part on the structure and dynamics of the regeneration of this forest. Without browsing, growth rate and species composition of the natural regeneration are mainly determined by the light conditions, which in turn are derived from difference silvicultural treatments. On the shelterwood and the clearcut plots height and height increment also increasingly depend on intra- and interspecific competition effects. The impact of ungulates brings about a complete change in the situation. A high percentage of fir and sycamore saplings is damaged. The survival rates of older fir plants are drastically reduced. In all species, except spruce, height is significantly reduced. A huge loss of estimated biomass was observed. Subsequently the interference processes amongst the saplings also changed. Competition, while still intensive, is no longer important.