Influence of ungulates on the vegetation composition and diversity of mixed deciduous and coniferous mountain forest in Austria

The often highly elevated stocks of ungulates (red and roe deer and chamois) in the Alps shape the composition of the woody vegetation. The aim of this study was to investigate the influence of ungulates on the mixed deciduous and coniferous mountain forest in the district of Reutte, which boasts the highest density of ungulates in Tyrol (Austria), with a special focus on the effect of browsing by ungulates on plant diversity of the herb layer, different shrub layers. and the tree layer. Our results showed that within the fenced ungulate exclosures, (1) the composition of trees shifted towards fir (Abies alba) and various deciduous trees, whereas outside the fences, spruce became the dominant species; (2) the cover of dwarf shrubs and upper and lower shrub layers (1.3–5.0 and 0.5–1.3 m, respectively) increased significantly; (3) the cover of grasses decreased significantly and (4) the diversity decreased as an increase in the diversity of the tree and shrub layer was overcompensated by a significant decrease in the diversity of the undergrowth vegetation. Browsing by ungulates benefited grass species in the understory and altered the relative abundance of tree species in the lower layer which could, over time, result in compositional shifts in the canopy.