Event Detail

Event Type: 
Department Colloquium
Wednesday, January 21, 2009 - 04:00
1001 Kelly Engineering

Speaker Info

Colorado State University

The persistence of ecological systems also depends on their response to disturbance. In recent years, study of complex adaptive systems (e.g., engineered, weather, biological systems) has begun to impact ecological thinking suggesting, among other things, that resilience to disturbance in ecosystems may be enhanced by intermediate levels of modularity within the system. Spatial modularity, corresponding to the level of aggregation or clustering of individuals, affects a population's recovery following a spatially spreading disturbance. My simulation results showed that populations with intermediate spatial modularity had the largest remaining population post-disturbance and that this intermediate optimum results from a tradeoff in local versus global connectedness. Spatial patterns with intermediate modularity can be generated by organisms with rare long distance dispersal. Both fairly small and large amounts of long distance dispersal give similar times until the system returns to the original population size post-disturbance, although large amounts of long distance dispersal are optimal. This result suggests that different forms of resilience (population remaining vs. return time) do not necessarily tradeoff with one another, contrary to what has been suggested in the literature. Extensions to this work suggest that under constrained tradeoffs, individual-level selection on dispersal ability can result in rare long distance dispersal of organisms and intermediate spatial modularity at the system-level. I am currently exploring these ideas in a multispecies context, looking at how dispersal patterns constrain the persistence of detritus-detritivore interactions. Background: Dr. Colleen Webb received a B.S. in Applied Mathematics from The University of Chicago (1993), a M.S. in Biology from The University of Oregon (1994), and a Ph.D. in Ecology and Evolutionary Biology from Cornell University (2001). Her dissertation work focused on modeling how natural selection can result in extinction in certain types of ecological interactions. Dr. Webb went on to a joint postdoctoral position at Princeton University and The Santa Fe Institute. Her postdoctoral work focused on the role of spatial modularity in resilience. In 2003, she became an Assistant Professor in Biology at Colorado State University with a joint appointment in Mathematics. She is also an External Professor at The Santa Fe Institute. Dr. Webb's current work involves theoretical evolutionary ecology approaches to problems of how systems persist including continuing her work on spatially explicit resilience models, as well as developing trait-based approaches to understanding ecosystem level response to environmental change, and investigating mechanisms of persistence for highly virulent diseases.