Sensitivity of plant–pollinator–herbivore communities to changes in phenology

For many species in seasonal environments, warmer springs associated with anthropogenic climate change are causing phenological changes. Within ecological communities, the timing of interactions among species may be altered if the species experience asymmetrical phenological shifts. We present a model that examines the consequences of changes in the relative timing of herbivory and pollination in a community of herbivores and pollinators that share a host plant. Our model suggests that phenological shifts can alter the abundances of these species and, in some cases, their population dynamics. If historical patterns of interactions in a community change and herbivores become active before pollinators, the community could see a reduction in pollinators and an increase in herbivores, while if pollinators become active before herbivores, there could be a loss of stable coexistence. Previous studies have warned of the potential for climate change to cause large phenological mismatches whereby species that depend on one another become so separated in time that they can no longer interact. Our results suggest that climate change-induced phenological shifts can have a major impact on communities even in cases where complete phenological mismatches do not occur. © 2009 Elsevier B.V. All rights reserved.