Multi-scale investigations of gray treefrong movements: patterns of migration, dispersal, and gene flow

Abstract

The movement of individuals within and among populations has been recognized as an important determinant of the persistence of species. Fragmentation of terrestrial landscapes has exacerbated the need to understand the effects of changes to the core habitat of mobile organisms and has led to an increase in the use of metapopulation theory in conservation biology. I have determined the spatial scale of migratory movements, the location of overwintering locations, and the biotic and abiotic factors determining microhabitat use. Further, I have demonstrated the effects of matrix composition on the frequency of inter-pond movements and elucidated historical patterns of gene flow across central Missouri. My data indicate that migration through terrestrial habitat adjacent to breeding sites is extensive. Furthermore, dispersal success is affected by matrix composition and inter-pond distance, but juveniles and adults are differently inhibited. Lastly, the type of metapopulation dynamics exhibited by associations of gray treefrog populations depends upon the degree of geographic isolation and the presence of barriers to movement.