PARENT SESSION
Oral Session #79: Conservation Ecology: Biodiversity Case Studies and Models. Presiding: T. Rooney.
Friday, August 10, 2001. 8:00 AM to 12:00 PM. Hall of Ideas J.

Breeding bird communities of closed-canopy boreal mixedwood forests following fire and logging disturbance.

CAMPBELL, BRIAN¹, MALCOLM, JAY¹, ¹

ABSTRACT- The southern boreal mixedwoods of Ontario harbor one of the most diverse assemblages of breeding birds in Canada. Within this region, forest harvesting represents a major form of disturbance that may alter the composition of breeding bird communities relative to natural disturbance regimes. We surveyed bird communities of closed-canopy, post-fire and post-harvest mixedwood forests in six replicated regions of northeastern Ontario and used general linear modeling and rarefaction methods to compare the relative influence of stand age, stand structure and landscape composition on breeding bird species composition and richness. Local habitat and landscape matrices explained 40.0% of bird community composition, with 25.0% explained by stand structure, 10.0% explained by landscape composition, and 5.0 % shared by both datasets. Post-fire sites were characterized by significantly greater heterogeneity of forest canopy structure, stand age, coarse woody debris, and landscape patchiness relative to post-harvest sites. Three guilds (overstory nesters, winter residents and neotropical migrants), and five species characteristic of mature, mixed-coniferous forest were significantly more abundant in post-fire versus post-harvest sites. Conversely, one guild (ground nesters) and five species characteristic of deciduous forest habitats were significantly more abundant in post-harvest sites. Our results indicate that, in addition to stand age and tree species composition, disturbance history and landscape composition need to be incorporated in forest management planning for biodiversity conservation.

KEY WORDS: boreal mixedwoods, breeding birds, disturbance regimes, bird conservation