Physiological vagility: correlations with dispersal and population genetic structure of amphibians.
Physiological vagility represents the capacity to move sustainably and is central to fully explaining the processes involved in creating fine-scale genetic structure of amphibian populations, because movement (vagility) and the duration of movement determine the dispersal distance individuals can move to interbreed. The tendency for amphibians to maintain genetic differentiation over relatively short distances (isolation by distance) has been attributed to their limited dispersal capacity (low vagility) compared with other vertebrates. Earlier studies analyzing genetic isolation and population differentiation with distance treat all amphibians as equally vagile and attempt to explain genetic differentiation only in terms of physical environmental characteristics. We introduce a new quantitative metric for vagility that incorporates aerobic capacity, body size, body temperature, and the cost of transport and is independent of the physical characteristics of the environment. We test our metric for vagility with data for dispersal distance and body mass in amphibians and correlate vagility with data for genetic differentiation (F'(ST)). Both dispersal distance and vagility increase with body size. Differentiation (F'(ST)) of neutral microsatellite markers with distance was inversely and significantly (R2=0.61) related to ln vagility. Genetic differentiation with distance was not significantly related to body mass alone. Generalized observations are validated with several specific amphibian studies. These results suggest that interspecific differences in physiological capacity for movement (vagility) can contribute to genetic differentiation and metapopulation structure in amphibians.
Department of Biology, Portland State University, Portland, Oregon 97207; 2Department of Herpetology, California Academy of Sciences, San Francisco, California 94118; 3Department of Biological Sciences, University of North Texas, Denton, Texas 76203; 4Department of Biology, Eastern Washington University, Cheney, Washington 99004.
Stanley S
SS
Hillman
Robert C
RC
Drewes
Michael S
MS
Hedrick
Thomas V
TV
Hancock
D000663:Amphibians / Q000235:genetics / Q000502:physiology*; D063147:Animal Distribution; D000818:Animals; D001835:Body Weight; D003246:Conservation of Energy Resources; D004777:Environment; D018740:Genetic Heterogeneity; D005828:Genetics, Population; D018895:Microsatellite Repeats; D008957:Models, Genetic