Woodpeckers as Focal Species for an Ecological Network Design in the Po Plain (Northern Italy)

Habitat fragmentation is a major threat to biodiversity. Thus the improvement of connectivity in highly fragmented landscape is a crucial issue for animal conservation. In this study we designed an ecological network for woodland birds in the agricultural landscape of the Po Plain (Northern Italy) using woodpeckers (great spotted woodpeckers Dendrocopos major, lesser spotted woodpeckers Dendrocopos minor and green woodpeckers Picus viridis) as focal species. Habitat suitability for woodpeckers was evaluated by generalized linear models and multimodel inference handling data on land use, landscape metrics and surrounding context. Circuit theory was used to define the best corridors network, subsequently compared with the distribution of other woodland birds. Wooded riversides, extended agro-forestry plantations and scattered natural forest stands appeared as the best components of a corridor design for woodland birds. The fact that other species threatened by forest fragmentation (e.g. Eurasian nuthatches Sitta europaea and marsh tits Poecile palustris) mainly occurred in the corridors network defined in the present study emphasized these results.