Physiological Vagility: Correlations with Dispersal and Population Genetic Structure of Amphibians

Abstract

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.

Diversification of the rainfrog Pristimantis ornatissimus in the lowlands and Andean foothills of Ecuador

“…This is particularly true for Pristimantis , a genus with ~500 recognized species [24], where phylogeographic studies usually find marked genetic structure [56,63,64,65]. Two main factors seem to explain the extremely high species richness in Pristimantis , a high mutation rate [66] and low vagility [67]. Low vagility can be influenced by several variables, including size (i.e., dispersal distance increases with body size; [50,67]), physiological breadth [68,69], and reproductive mode (i.e., terrestrial).…”

“…Two main factors seem to explain the extremely high species richness in Pristimantis , a high mutation rate [66] and low vagility [67]. Low vagility can be influenced by several variables, including size (i.e., dispersal distance increases with body size; [50,67]), physiological breadth [68,69], and reproductive mode (i.e., terrestrial).…”

Amphibian population genetics in agricultural landscapes: does viniculture drive the population structuring of the European common frog (Rana temporaria)?

“…Beside habitat loss and fragmentation of remaining suitable habitats or populations, agriculture often requires the development of irrigation, drainage and/or retention systems, which can impact the availability and quality of amphibian breeding sites. Yet despite their limited dispersal capacity compared with other vertebrates (Hillman et al, 2014), amphibians have been able to persist in agricultural landscapes by adapting to the altered availability of breeding sites (Mann et al, 2009). In agricultural landscapes, breeding habitats are often completely surrounded by arable land (Berger, Pfeffer & Kalettka, 2011).…”

Chromosomal diversity in tropical reef fishes is related to body size and depth range

“…Body size is strongly correlated with dispersal ability in a variety of organisms (Hillman et al, 2014;Pyron, 1999). However, in marine environments, most organisms disperse as larval propagules through ocean currents (Shanks et al, 2003).…”