Search ARMI Database

The dynamic geological and climatic history of northwestern North America has made it a focal region for phylogeography. We conducted a range-wide phylogeographic analysis of the spotted frog complex (Rana luteiventris and R. pretiosa) across its range in northwestern North America to understand its evolutionary history and the distribution of clades to guide conservation of R. pretiosa and Great Basin R. luteiventris, both candidates for listing under the U.S. Endangered Species Act. Mitochondrial DNA sequence data from a segment of the cytochrome b gene were obtained from 308 R. luteiventris and R. pretiosa from 98 sites. Phylogenetic analysis revealed one main R. pretiosa clade and 3 main R. luteiventris clades, 2 of which overlapped in southeastern Oregon. The 3 R. luteiventris clades were separated from each other by high levels of sequence divergence (average of 4.75–4.97%). Two divergent clades were also uncovered within the Great Basin. Low genetic variation in R. pretiosa and the southeastern Oregon clade of R. luteiventris highlights their vulnerability to extinction.

We examined dispersal rates in Columbia spotted frogs (Rana luteiventris) using capture–recapture analysis of over 10,000 frogs in combination with genetic analysis of microsatellite loci in replicate basins. We found that frogs had exceptionally high juvenile dispersal rates over long distances, large elevation gains and steep inclines that were corroborated by genetic data showing high gene flow.

Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, to investigate the effects of landscape structure on patterns of gene flow.

In California, overwintering tadpoles have been reported for only two ranid species: Rana muscosa (mountain yellow-legged frog) (Stebbins 1985) and R. catesbeiana (bullfrog) (Behler and King 1979; Leonard et al. 1993). Storer (1925) states that R. aurora spend 4 - 5 months as larvae with metamorphosis typically taking place between July and September. We report here our observations of Rana aurora draytonii (California red-legged frog) tadpoles overwintering at 11 sites spread over four counties in central coastal Cali-fornia. We define overwintering as spending the winter (No-vember - February) in the larval stage (< Gosner stage 40; Gosner 1960).