Influence of forest stand structure on the occurrence of bird community in Skalná Alpa National Nature Reserve in the Veľká Fatra Mts. (West Carpathians)

The study deals with the influence of the structure, texture and dynamics of a spruce-beech primeval forest on the bird community in Skalná Alpa National Nature Reserve in the Veľká Fatra Mts. (West Carpathians, Slovakia) in the years 1982-2002. The abundance of Norway spruce (Picea excelsa Lam.) was highest both in the optimum and decomposition stage. In the growth stage the number of Norway spruce (Picea excelsa Lam.) trees was quite low. The texture of spruce-beech virgin forest was very variable. Percentage ratios of individual stages on the area of 42.16 ha were as follows: growth stage 38.3%, optimum stage 20.1% and decomposition stage 41.6%. Altogether 46 bird species were represented in the bird community during the spring season. Mean total density was 85.8 ind/10 ha. The bird community consisted of 52 species in the summer season, 45 in the autumn migration season, 34 in the winter season, and of 47 in the spring migration season. The highest density was found in the bird community during the autumn migration season (109.8 ind/10 ha), the lowest in the winter season (24.6 ind/10 ha). During the spring migration season, both the spectrum of bird species and total density of bird community increased by the number of migratory species that came back from winter habitats.