Seasonal dynamics of waterbird assembly mechanisms revealed by phylogenetic and functional diversity in a subtropical wetland

Despite growing interest in phylogenetic and functional methods in ecological assembly, less attention has been paid to seasonal variation patterns of migrant species. Migrants can rapidly mediate influences of species interactions and environmental factors through seasonal movement, suggesting dynamical relative importance of different assembly mechanisms among seasons. Here we describe seasonal dynamics in phylogenetic and functional diversity of waterbirds in Mai Po Wetland, in a subtropical region with significant predictable temporal variation. Phylogenetic and functional structure of α diversity varied seasonally. Specifically, phylogenetic structures clustered in summer, while being over-dispersed in winter. However, phylogenetic structure in spring and autumn was intermediate with a transition to random. Functional structure was clustered in spring but showed over-dispersion in the other three seasons. For β diversity, summer and winter assemblages had two distinct groups, while...