May 18 2011

12:00 LSB 2320

Elsa Cleland
UC San Diego

The role of timing in plant community responses to global change and biological invasions


Abstract: Phenology, or the seasonal timing of activity, is an important trait that can contribute to temporal resource-partitioning among species, and hence plays a role in both community assembly and ecosystem functioning. Shifting phenology observed worldwide provides some of the best evidence that species and ecosystems are already responding to global change, and may result in substantial reorganization of plant communities. For instance, evidence from the Jasper Ridge Global Change Experiment shows that species can respond to different aspects of global change in diverse ways, resulting in decreased phenological complementarity that could reduce local species richness over time. In a broader context, a meta-analysis of species phenological responses to warming finds that species that cannot "track" climate are at increased risk of decreased performance. Finally, invasion by exotic species is another aspect of global change where phenology may play a critical role. An experiment in a Southern California coastal sage scrub community found that abundant exotic annual grasses became active earlier than native species under ambient rainfall regimes, potentially a result of a "seasonal priority effect." A summer watering treatment prompted the exotic grasses to germinate and subsequently die, leaving the native species to dominate the assemblage, suggesting a promising strategy for manipulating phenology in the context of ecological restoration.















































































































































































































































































































































































































































































































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