Forest soil degradation in slopes of the low mountain range of Central Europe - Do deer matter?

The study area is located in the low mountain range of Central Europe (Eifel) and characterized by a, marked relief and high game densities. Especially red deer populations, calculated at 20 ind./100 ha, surpass the carrying capacity of the forests observed. Trampling (by red deer and moufflon) and, rooting (wild boar) result in extensive soil disturbances, visible as soil profile mixture and soil erosion. We examined eight oak forests (Quercus petraea) located on slopes ranging from 24 to 34 degrees. Four sites are exposed to the southwest (windward) and four sites are exposed to the northeast (leeward), each containing two sites with disturbed and two with undisturbed soils. The content of macronutrients (Ca2+, Mg2+, K+), pH-value and Al3+ content as well as biotic soil properties such as abundance of soil, mesofauna. (Collembola, Oribatei) were mainly affected by exposition with higher values (lower values for Al3+) at leeward sites. In contrast, organic carbon (C-org) and nitrogen (N-t) of the upper soil depended exclusively on soil disturbance (ANOVA) with lower contents in disturbed soils. Microbial activity and biomass as well as PO43--P and NO3--N contents were significantly influenced by both factors. We found lower values at disturbed windward sites. The results clearly demonstrate the impact of game on soil degradation especially at windward sites.