Bird assemblages in silvicultural habitat mosaics in southern Finland during the breeding season

Abstract

We studied the significance of successional forest mosaics, created by modern forestry, for forest birds by censusing breeding birds during three summers in 12 study areas with variable habitat composition and configurations and in a reference area of old forest. The number of bird species relative to sample size didnot differ significantly between the silvicultural mosaics and old forest . However, in the silvicultural mosaics the total bird abundance was only about one third of that in the reference area . The relative abundances of different species also differed considerably . We divided the bird species into five groups on the basis of their observation frequencies and the way in which they used the silvicultural mosaics. The mosaics provided nesting habitats for the most common forest birds and for species favouring open habitats and forest edges. All other forest species visited the mosaics more or less irregularly. The total bird abundance in the silvicultural mosaics increased with habitat diversity, habitat productivity and the proportion of forested habitats . The effects of management practices on birds are discussed.