The Long-Lasting Territories of Forest Apex Predators Sustain Diverse Bird Communities throughout the Year

Abstract

Apex predators, such as raptors, are used as surrogates to attain conservation objectives; however, their presence in a particular area does not necessarily mean long-term occurrence. Here we used data on long-lasting (20–40 years) territories of two generalist raptors: the diurnal Northern goshawk and the nocturnal Ural owl in deciduous and coniferous forests of southern Poland to assess their role as hotspots of bird diversity. Species richness and abundance of birds were much higher in the long-lasting territories of both apex predators than in random never-occupied sites and this pattern was common for breeding and wintering periods. These differences were more pronounced in deciduous than coniferous stands. Rare bird species (e.g., annexed in the Bird Directive of the European Parliament and of the Council on the conservation of wild birds such as some woodpeckers and flycatchers) were found to be particularly associated with long-lasting territories of raptors. Long-lasting territories were also characterized by greater forest habitat quality (e.g., higher number of old trees and deadwood) with lower management intensity. These results strongly point to the role of long-lasting territories of raptors as surrogates of biodiversity. Such territories, if known in forests, could be excellent for the designation of protected areas or logging there should at least be reduced to allow for the continuous breeding of apex predators and associated bird assemblages.