Traits and ecological space availability predict avian densities at the country scale of the Czech Republic

Species geographical distributions and abundances are a central focus of current ecological research. Although multiple studies have been conducted on their elucidation, some important information are still missing. One of them is the knowledge of ecological traits of species responsible for the population density variations across geographical (i.e. total physical area) and ecological spaces (i.e. suitable habitat area). This is crucial for understanding how ecological specialisation shapes the geographical distribution of species, and provides key knowledge about the sensitivity of species to current environmental challenges. Here, we precisely describe habitat availability for individual species using fine-scale field data collected across the entire Czech Republic. In the next step, we used this information to test the relationships between bird traits and country-scale estimates of population densities assessed in both geographical and ecological space. We did not find any effect o...