October 13 2010

12:00 LSB 2320

Michael Allen
Center for Conservation Biology, UC Riverside

Large Disturbances and Mycorrhizae: Legacies, Succession, and Long-Term Ecosystem Implications


Large disturbances occur at repeated but infrequent intervals. Their impacts are spread across landscapes, such that a single event affects different communities and successional seres. Examples that I will address include Hurricane Wilma in the Yucatan Peninsula in 2005, the volcanic eruption of Mount St. Helens of 1980, and the severe 2003 drought across the southwest US forests. Mycorrhizae are mutualistic associations between plants and fungi, which are ubiquitous across terrestrial ecosystems. In general, mature ecosystems are more intensely affected by the disturbance than early-seral communities, such as high mortality of large trees. However, the fungi that interact with the surviving trees utilize physiological mechanisms that facilitate survival of mycorrhizal fungi and their ecosystem functioning. In early seral systems biotic interactions, particularly animals, subsequently re-disturb sites, and facilitate early-seral vegetation and re-establishment of mycorrhizae. Although these mechanisms all facilitate succession, legacy effects persist.















































































































































































































































































































































































































































































































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