Phylogeography and conservation genetics of two endangered amphibians, Blanchard's cricket frog (Acris crepitans blanchardi) and the Puerto Rican crested toad (Peltophryne lemur).

摘要

I investigated the genetic diversity and structure of two endangered amphibians with the goal of developing conservation recommendations. The Puerto Rican crested toad (Peltophryne lemur) is a critically endangered tropical bufonid, for which one wild population remains. Declines are primarily due to habitat modification, and recovery efforts include captive breeding of northern and southern populations. In contrast, Blanchard's cricket frog (Acris crepitans blanchardi) is a temperate hylid that is declining at the northern edge of its range, but for which many large southern populations exist. The causes of declines are not well understood, and few conservation efforts have been initiated. I profiled the captive and wild populations of P. lemur, and 185 locations encompassing all Acris taxa, at the mitochondrial control region and several novel microsatellite loci. P. lemur had moderate microsatellite allelic diversity, but northern and southern populations were each fixed for a different mitochondrial haplotype. The northern population possessed many private microsatellite alleles that, when combined with habitat differences, may be indicative of adaptive variation. Given the highly inbred nature of the northern population and its likely extirpation, I recommend that a third breeding colony be established in which northern and southern individuals are mixed to preserve any unique northern traits. Profiling of A. c. blanchardi revealed a relatively uniform northern clade and a substructured southern clade. Low genetic diversity in the north may be contributing to declines. The south was likely a refugium during Pleistocene glaciations, while the north experienced repeated population expansions and contractions. Phylogenetic analysis of all Acris species and subspecies indicated that substantial revisions to current taxonomy and distributions are required, including elevation of A. blanchardi to species status. Diversification within this complex primarily reflects large rivers, changes in elevation, and Pleistocene glaciations. Recognition of A. blanchardi as a species increases the urgency of conservation actions, and the distinctiveness of northern populations suggests that they may possess adaptive traits that should be conserved. Phylogeographic and spatial analysis provide a framework for actions such as reintroductions. Overall, this research demonstrates the importance of incorporating genetic information into recovery recommendations and management actions for threatened species.;Keywords: amphibian, anuran, declining amphibian populations, endangered species, Acris, Peltophryne lemur, cricket frog, Puerto Rican crested toad, microsatellite, mitochondrial DNA, control region, phylogeography, genetic structure, conservation genetics, Pleistocene glaciation