BERNARD, Alaina B.*; JENKINS, David G.; Department of Biology, University of Central Florida; Department of Biology, University of Central Florida: Metapopulation dynamics in two small-world networks

Small-world networks are classified as scale-free, broad-scale, and single-scale and are model interactions among units in diverse complex systems (e.g., rivers, the world-wide-web, and protein interactions). Scale-free networks have connectivity distributions that follow a power law (and have hubs) whereas single-scale networks have a random connectivity distribution (broad-scale networks are intermediate). The application of small-world networks could increase the understanding of complex ecosystems and enable better conservation policies for at-risk populations and habitats. We experimentally tested the effect of network structure on metapopulation dynamics using the model organism, Daphnia magna. Ten patches were connected to each other according to rules established for single-scale and scale-free networks (two replications of each). Population sizes were censused every other day for two months. Single-scale and scale-free networks were not significantly different for total metapopulation number and exhibited similar variation in population size among local populations, but single-scale metapopulations were more consistent through time. This result suggests that endangered species functioning as scale-free metapopulations are more vulnerable to allee effects than those functioning as single-scale metapopulations. We are conducting additional experiments to examine the effects of random and targeted attacks (i.e., population removals) in larger network structures.