Data from: 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 spring and autumn assemblages were mixed. Thus, waterbird
assemblages were primarily shaped by interspecific competition in winter.
Random processes tended to shape assemblage in spring. Environmental
factors played a more important role in summer . In addition, phylogenetic
distance of probability of co-occurrence of species pairs was
significantly larger in winter than in summer. These results suggest that
the relative importance of assemblage mechanisms can vary seasonally in
response to changing environmental conditions, suggesting that studies
attempting to infer a single dominant assembly mechanism may ignore
important assembly processes. Temporal shifts in assembly mechanisms may
play an important role in maintaining diversity of subtropical and
temperate wetlands and perhaps other dynamic systems.