Bird community in a Beech forest in Lower Savinja Valley (Slovenia)

Vogrin M.



Abstract:

Bird census work was carried out in the forest (30.8 ha) at the edge of the Dobrovlje karst plateau in Lower Savinja VaIley (Slovenia), belonging to the Luzulo-Fagetum phytocenosis and Blechmo-Fagetum forest. The main species of the forest are: Fagus sylvatica, Quercus petraea, Pinus sylvestris and Picea abies. Twenty-six bird species were reported in the forest and the average density was 30.2 pairs/10 ha. The abundance (biomass) of the bird community is 2078 g/10 ha. The highest densities of breeding pairs were noted for Parus ater and Erithacus rubecula. The Index of Diversity (H’) was 2.82 and the Evenness Index (Je) was 0.87. Breeding communities were also analyzed in relation to the nesting site, feeding and migratory habits. Among the breeding species, five were trans-Saharian migrants and five were only short-distance migrants. Nine species (33.6 %) are insectivorous (carnivorous) species, four (15.4 %) are herbivorous and thirteen (50 %) are omnivorous. The density of the breeding avifauna in the beech forest depended primarily on the density of species nesting in the crowns of trees and from hole-nesters (both 11.4 pairs/10 ha), on the density of omnivorous species (19.1 pairs/10 ha) and residents (16.2 pairs/10 ha). The breeding population of the Zovnek beech forest has a species composition markedly different from other forests compared here(Sorensen’s lndex of Similarity varied from 27 to 75, and the Renkonen lndex varied from 14.3 to 61.2).