Climate change, phenology and the nature of consumer–resource interactions: advancing the match/mismatch hypothesis

Introduction Understanding how species cope with ecological and environmental variation is a fundamental concern of ecology. Over the course of their lives, many organisms alter their phenotypes in response to biotic and abiotic pressures (Miner et al. 2005), responses that cascade through the food web to, in turn, affect the dynamics of species interactions. These effects, called trait-mediated effects, are pervasive in ecological communities, and their study has offered new insights into community ecology, a subject previously dominated by a density-mediated understanding of species interactions (Werner and Peacor 2003). Most analyses of trait-mediated effects take a top-down perspective where variation in consumer traits causes phenotypic responses by prey species. These phenotypic responses include behavioural, morphological and/or physiological plasticity that have ramifying consequences for the food web by influencing how predators and prey interact (Werner and Peacor 2003). This top-down perspective on the influence of traits in communities suggests that it is consumers that determine the nature and strength of the mediated effects. Climate change is anongoing global perturbation that also affects thedensities and traits of interacting species, although these effects are not necessarily related to food web trade-offs. Cohesive shifts in phenology – the timing of periodic biological events, such asmigration, flowering ormating – reveal the global scale of climate change’s influence on species’ traits (Parmesan and Yohe 2003; Root et al. 2003). These phenological changes affect conditions that influence