Resumen de Relationships between forest landscape structure and avian species richness in NE Spain
Assu Gil-Tena, Olga Torras, Santiago Suara
Aims: To examine how forest landscape structure (including composition and configuration features) affects forest bird species richness at the scale of 10 x 10 km in Catalonia (NE Spain), considering different degrees of specialization of forest birds.
Location: NE Spain.
Methods: Bird presence data were obtained from the Atlas of Spanish Breeding Birds and forest landscape variables were extracted from the Spanish Forest Map developed within the Third Spanish National Forest Inventory. The analyses were carried out through multiple linear regressions and considering multicollinearity and spatial autocorrelation problems.
Results: Forest landscape characteristics influenced more on specialist than on generalist bird species richness, explaining 62 % and 52 % of total variation, respectively. Forest area was the most important landscape factor, although bird species richness was also considerably favoured by tree species diversity and by the abundance of coniferous forest. Forests with too closed canopy cover (equal or bigger than 80 %) supported less bird species. The effects of forest landscape configuration were weak compared to composition; the only significant configuration index was the mean circumscribing circle index, as a potential indicator of the naturalness of forest landscapes.
Conclusions: Forest landscape management should focus on forest habitat availability and forest structure features rather than on a particular forest landscape configuration, promoting an amalgam of forest tree species and avoiding an excessively closed canopy. However, and especially for generalists, it is necessary to consider the characteristics of other non-forest land cover types for an adequate management and conservation of forest bird communities.
