PATTERNS AND PROCESSES OF COMMUNITY STRUCTURE IN BOREAL BIRD ASSEMBLAGES

Sarah Wyshynski

University of Guelph, 2004

Advisor: T.D. Nudds

As timber harvest replaces fire as the main agent of disturbance in the boreal forest, managers are striving to minimise the effects of forestry by emulating patterns of natural disturbance. I used randomized null models with presence/absence and abundance data to investigate the relative contributions of local vs. regional processes in structuring local avian communities, and tested for redundancy in avian assemblages. Despite the notoriously variable nature of boreal forests generally, local (stand level) bird assemblages exhibited highly non-random structure, regardless of stand origin, consistent with the hypothesis that strong local processes, such as competition, structure avian communities. Further, local community structure more strongly depended on species’ ecological traits, rather than on taxonomic identity, suggesting functional redundancy. Because ecosystem function may persist in the absence of some species if functionally similar species replace them, maintaining a diversity functional groups may be an effective means to ensure ecological integrity in Ontario’s boreal forest.