OOS 27

Demographic Buffering Beyond the Comfort Zone: Species’ Responses to Anthropogenic Disturbances

Many species across the animal and plant kingdom have evolved traits and life-history strategies to adapt to frequent natural disturbances. Humans, managing a large part of the world´s natural areas, have altered the frequency and severity of such disturbance regimes and introduced novel disturbances. Such changes may affect demographic processes (e.g. survival, growth, reproduction) of disturbance-adapted species, resulting in changed population dynamics and structure and vulnerability to local extinction. Synthesizing information on how humans change population dynamics of such species, either through direct alterations (e.g. fire suppression, dam-controlled flooding, deforestation) or through climate change (droughts, hurricanes, frosts), is crucial as the anthropogenic footprint will likely increase in the future. Theoretical models, supported by empirical studies, predict that species living in frequently disturbed habitats are more flexible to adapt to changes in disturbances than those in more stable environments. Recent studies, however, suggest that some these disturbance-adapted species, long believed to profit from novel disturbance regimes, may indeed be at the risk of extinction. The discrepancies between theory and current empirical studies may be partly explained by (a) an incomplete knowledge of the life cycle of disturbance-adapted species and (b) the multiple and complex ways in which humans change disturbance regimes. This session will aim to address the question “What are the life-history peculiarities of disturbed-adapted species that allow them to buffer against anthropogenic effects, and under what circumstances are these strategies not successful? Speakers will offer novel perspectives to this timely question by drawing from various disturbance types (fires, droughts, hurricanes, deforestation and frost) and taxonomic groups (plants and insects).