PARENT SESSION
Contributed Oral Session 5: Aquatic Ecology: System Heterogeneity
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 515 A, Level 5, Palais des congrès de Montréal
Movement patterns of an invasive freshwater snail: An efficient modeling approach.
Snider, Sunny*,1, Gilliam, James1, 1 North Carolina State University, Raleigh, NC
ABSTRACT- Movement of animals across complex landscapes is fundamental to many ecological processes from species invasions to gene flow. Modeling such processes requires attention to both environmental heterogeneity and phenotypic heterogeneity. We postulated variations on the simple advection-diffusion model as a priori working hypotheses to address how local movement patterns of Tarebia granifera, an invasive aquatic snail in Trinidad, West Indies, are affected by environmental heterogeneity, in terms of food resources, and phenotypic heterogeneity, in terms of body size. To test our hypotheses we measured individual snail movements in experimental streams at high and low resource treatments. Using these experimental movement data, we examined the dependency of model selection on resource level and body size. We assessed the ability of these models to predict population level movement behaviors using Akaike's Information Criterion (AIC). At low resources, large individuals moved faster than small individuals and including size dependency in the model improves model performance. At high resources, individuals moved upstream together as a wave and body size differences largely disappeared. These findings show empirically how 1) environmental heterogeneity, or resource level, restructures animal movement patterns for this species and 2) the influence of population heterogeneity on snail movement behaviors is context dependent. Finally, we illustrate how this approach may be used to efficiently model animal movement patterns. Modeling animal movement efficiently will contribute to our understanding of organism spread, and may provide timely, yet still scientifically robust, predictions for a host of ecological applications such as biological invasions.
Key words: movement, streams, invasion, snails