March 24, 2011 – "Maintaining and Restoring Biodiversity in a Human-Dominated World"
John Chase, Professor of Biology and Director, Tyson Research Center, Washington University in St. Louis
Biodiversity in any given locality is determined by a combination of ecological factors, including those that are more 'deterministic' (e.g., environmental conditions, interspecific interactions, and those that are more 'stochastic' (e.g., dispersal limitation, colonization/extinction dynamics). Anthropogenic activities alter both of these processes, and thus it is important to recognize their relative roles when attempting to conserve and/or restore biodiversity in the face of a growing human population. Ecological studies have tended to focus on the small-scale processes that interact to determine how many species can co-occur in a given location. However, at larger scales, factors that influence the site-to-site variation in species composition are critical to understanding biodiversity at larger spatial scales. Chase first develops a conceptual framework for the contributions of deterministic and stochastic factors to site-to-site variation using simple probability theory. Next, using a series of long-term experiments and observations, he shows how deterministic and stochastic processes interact to structure the biodiversity at larger spatial scales. He discusses how this perspective changes our understanding of how habitat loss, habitat degradation, and habitat restoration influence patterns of biodiversity, and compare those outcomes among regions that vary in their incipient levels of biodiversity (i.e., biodiversity hotspots versus coldspots).
Jon Chase's research interests are broad but generally focus on the rules (or lack thereof) underlying the diversity, distribution, and abundance of animal and plant species from the population/community/ecosystem perspective. He is particularly interested in the patterns and processes that develop at the interface between local and regional spatial scales. To approach these questions, he combines mathematical theory, observations and statistical approaches, rigorous experimentation in both the field and lab, and a knowledge of natural history.