New Harvard Forest Publication: Predicting Species Abundance After Habitat Loss

Plant and animal population sizes inevitably change following habitat loss, but the mechanisms underlying these changes are poorly understood. In a new study published in PLoS Biology, University of Vermont biology professor Nicholas Gotelli and Harvard Forest senior ecologist Aaron Ellison provide the first experimental confirmation that trophic structure can determine species abundances in the face of habitat loss. In a carefully constructed field experiment Gotelli and Ellison altered habitat volume and eliminated top trophic levels of the food web of invertebrates that inhabit rain-filled leaves of the carnivorous pitcher plant Sarracenia purpurea. Path models that incorporated food-web structure better predicted population sizes of food-web constituents than did simple keystone species models, models that included only single-species responses to habitat volume, or models including both food-web structure and habitat volume. In sum, the incorporation of trophic structure into ecological models may yield more accurate predictions of species abundance in a world where available habitats are shrinking and becoming increasingly fragmented.

Gotelli, N. J. and A. M. Ellison. 2006. Food-web models predict species abundances in response to habitat change. PLoS Biology 4(10): e324.