Seasonality in spatial distribution: climate and land use have contrasting effects on the species richness of breeding and wintering birds

Aim: Many studies have examined large-scale distributions of various taxa and their drivers, emphasizing the importance of climate, topography, and land-use. Most studies have dealt with distributions over a single season or annually without considering seasonality. However, animal distributions and their drivers can differ among seasons because many animals migrate to suitable climates and areas with abundant prey resources. We aim to clarify seasonality in bird distributions and their drivers.

Location: Japan.

Methods: We examined the effects of climate (annual mean temperature, snow depth), topography (elevation), and land use (extent of surrounding habitat) on bird species richness, in the breeding and wintering seasons separately, using nationwide data (254 forest and 43 grassland sites, respectively). We separately analyzed the species richness of all species, residents, short-, and long-distance migrants in forests and grasslands.

Results: In the breeding season, the ann...