Avian community assembly processes during primary succession

Background/Question/Methods

Colonization and community assembly dynamics incorporate both local and regional processes.  For animals with high dispersal capabilities like birds, dispersal is unlikely to constrain colonization, though some studies of smaller-scale disturbance have highlighted the importance of dispersal at the local scale.  Community ecologists have developed competing models of community assembly, many of which are still debated.  The eruption of Mount St. Helens in 1980 provided the opportunity to examine community assembly processes as they occur during primary succession.  We examine the dynamics of local community structure and composition of bird assemblages in primary successional habitats at Mount St. Helens in order to assess the role of competing community assembly models at different spatial and temporal scales. 

Results/Conclusions

Bird assemblages in primary successional habitats at Mount St. Helens currently demonstrate high beta-diversity across space but relatively low inter-annual turnover.  Preliminary results indicate that regional range size is an important predictor of local occupancy, but that habitat filtering is also occurring in these early successional environments.  Examining community patterns across time indicate that regional dispersal is more important at larger time scales.  Our findings stress the importance of considering temporal scales of regional patterns and local processes to understanding local community assembly.