Effects of habitat structure, floral composition and diversity on a forest bird community in north-western Italy

During the breeding period, I analysed bird community-habitat relationships in a managed broad-leaved forest of north-western Italy (a newly established nature reserve). Species richness, diversity, biomass and abundance of some ecological groups of birds were analysed with respect to habitat variables, summarising habitat structure, canopy and understorey floral composition. Two major patterns of relationships among bird and habitat were traced: the first involved changes in tree structure during their growth (canopy height and diameter of the dominant tree), the second was related to characteristics associated with floral richness. Bird diversity, species richness, the amount of hole nesters, of trunk and ground feeders were positively associated with stands age. The abundance of some groups of birds was positively related to plant species richness: understorey species richness influenced shrub feeders, shrub nesters and edge species; canopy species richness affected trunk feeders. Canopy species richness also affected bird diversity, richness, biomass, abundance of hole nesters, trunk feeders and forest interior species.