PARENT SESSION
Poster Session #37: Invertebrate Ecology.
Thursday, August 9, 2001. Presentation from 10:30 AM to 12:00 PM. Exhibition Hall

Effects of fire and clear-cut logging on the stability of beetle assemblages in boreal forests.

COBB, TYLER¹, JAMES, PAUL¹, VINEBROOKE, ROLF¹, ¹

ABSTRACT- There is increasing agreement among ecologists and boreal forest managers that the most sustainable forest harvesting strategies will be those that emulate natural disturbances. However, responses of boreal organisms to natural (e.g. fire) and anthropogenic disturbances (e.g. clear-cut logging) are poorly understood. We hypothesized that beetle assemblages in jack pine (JP) and spruce-aspen mixed wood (MW) forest stands are better adapted to fire than clear-cut logging due to the importance of fire in the boreal region. To test this hypothesis, we conducted an experiment that included three disturbance treatments (burned, clear-cut, control) nested within the two forest types. Key response variables included resistance (capacity to withstand disturbance) and resilience (recovery rate following disturbance) of beetle community biomass. Assemblages in both forest types appeared to be better adapted to the effects of fire than to clear-cutting, but for different reasons. MW assemblages were more resistant to the effects of fire, while JP assemblages were more resilient to this natural disturbance. In contrast, both assemblages were comparatively resistant, but not resilient to clear-cutting. Our findings show forest type-specific responses of beetle assemblages to fire and clear-cut logging and demonstrate differences between these two disturbances.

KEY WORDS: beetles, disturbance, resistance , resilience