Numbers of individuals and endemicity for birds in three study sites of the Himalayas-Hengduan mountains of China

1. Describing the patterns and revealing the underlying mechanisms responsible for variations in community structure remains a central focus in ecology. However, important gaps remain, including our understanding of species abundance. Most studies on abundance-based relationships are from either temperate ecosystems or tropical ecosystems, and few have explicitly tested abundance-based relationships across a temperate to tropical ecotone.
2. Here, we use a comprehensive dataset of breeding birds across elevation spanning a temperate to subtropical gradient in the Himalayas-Hengduan mountains of China to examine the relationship between species abundance and (1) elevational range size, (2) body size, (3) elevational range center and, (4) endemicity.
3. We tested a priori predictions for abundance-elevational range size relationship, abundance-body size relationship, and abundance-elevational range center relationship and explored how these relationships change along this temperate to sub...