Bird seasonal beta-diversity in the contiguous USA

Beta-diversity, the measurement of community changes along gradients, is an important component of diversity, and is needed to understand how local communities are assembled from a regional pool. Although they have rarely been quantified, seasonal changes in species composition have important management implications, as they can hamper the representativeness of snapshot community studies. The present study thus maps bird seasonal changes in species composition (beta-diversity) across the contiguous USA, using weekly data from the eBird project. Besides management implications, this map also provides insights into the mechanisms driving seasonal beta-diversity, namely that it is mostly related to the annual temperature range and the size of the species pool.