Impact of large herbivores on mountain forest stands in the Beskydy Mountains

Abstract

The impacts of three herbivorous mammals (brown hare Lepus europaeus, roe deer Capreolus capreolus and red deer Cervus elaphus) on woody species were investigated in the Kněhyně supra-regional biocentre (Beskydy Mountains, Czech Republic, 950–1257 m a.s.l.) in relation to forest management. The study focused on the question of whether large herbivores may prevent shrub layer development, and thereby disturb natural forest regeneration. Rowan ( Sorbus aucuparia) was used as a model woody species for the study. The browsing intensity on rowan annual shoots showed that large herbivores delayed the growth of saplings, though stand development was essentially not disturbed. Moderate winter browsing (approximately 30%) was determined by the fact that roe deer and red deer stay in the region only from spring to autumn and tend to move to lower altitudes during the period of continuous snow cover. The density of hares, which remain in the region throughout the course of the year is permanently low. Summer browsing is low (approximately 10%) as a result of a plentiful availability of good quality food in the vegetation period. Leaves of Rubus idaeus form approximately 80% by volume of the diet of roe deer and red deer, while brown hares feed on grasses. For the Kněhyně biocentre management, it appears unnecessary to take any regulation measures to reduce the impact of large herbivores on vegetation. Similar conclusions would probably apply to other mountain areas under the same conditions. However, this conclusion might not apply to other mountains where there are different environmental conditions (different density of large herbivores and different food supply in the herb and shrub layers).