OOS 9-7 - The importance of within-patch heterogeneity for metapopulation dynamics of a high elevation pine

Tuesday, August 8, 2017: 10:10 AM
Portland Blrm 256, Oregon Convention Center
Emily L. Schultz, Biosciences, Rice University, Houston, TX and Tom E. X. Miller, BioSciences, Rice University, Houston, TX

Many species are organized into metapopulations – disjunct local populations connected by dispersal. Current metapopulation models do not incorporate environmental variation experienced by individuals within populations, instead relying on average values for each population as a whole. However, when individual vital rates, such as growth, survival, and reproduction, respond to environmental variation in a nonlinear fashion, using average values can bias results. I used demographic data and dispersal data for whitebark pine (Pinus albicaulis) to parameterize a metapopulation model, incorporating the effect of nonlinear responses to within-patch variation in elevation and aggregation, to predict metapopulation dynamics and persistence. I compared the results to the dynamics and persistence predicted by a model that did not incorporate within-patch heterogeneity.


Most vital rates showed non-linear responses to elevation and density. However, the shape of the effect was not consistent across vital rates, and the strength of the effects depended on the size of the tree. This suggests that within-patch heterogeneity might affect the population dynamics, but the relationship will be complex and depend on interactions between the responses of different vital rates.