PS 84-207 - Assessing the dynamics of a generalist predator/prey model across different spatial configurations

Friday, August 11, 2017
Exhibit Hall, Oregon Convention Center
Rosa M. McGuire and Kurt E. Anderson, Department of Biology, University of California, Riverside, Riverside, CA

Habitat destruction and fragmentation are major human impacts. Microcosm experiments have shown that habitat fragmentation can alter the persistence and population densities of members of a community. Spatial heterogeneity allows recolonization from other patches resulting in long-term species persistence and preventing species from going extinct. Much of our understanding of these processes have come from protist microcosm studies. However, most microcosm studies of habitat fragmentation have focused on predator/prey interactions that include specialist protist predators. Here, we use protist microcosms to study the persistence of a predator/prey system using Amoeba proteus, a generalist predator, and Paramecium caudatum as prey. Unlike specialist predators, generalists are expected to be over represented in fragmented habitats and have longer persistence times, meaning that understanding their dynamics is important. Our study aims to understand and predict the ecological impacts of habitat fragmentation, a major concern in conservation biology. We will complete a study of population dynamics across different spatial configurations using both computer simulations and microcosm experiments. These results will be used to determine whether certain habitat configurations are better at maintaining persistence.


Experiments on patch colonization and chance of extinction have been completed and experiments on the functional response of the predator are still ongoing. Analyses using maximum-likelihood estimation (MLE) in R were used to obtain parameters for the predator/prey model. The value for the per capita growth rate of Paramecium caudatum obtained from MLE estimations was r = 0.2170687. When estimating dispersal of P. caudatum across a 2-patch system, we found that dispersal changes as a function of the distance between patches. The preliminary results for the functional response of Amoeba proteus show a Type II saturating curve. We will build a model using all these parameters and test it with microcosm experiments. We expect longer predator persistence times and greater variability among spatial configurations due to the generalist diet of our predator.