Genetic diversity in a narrowly endemic, recently described dusky salamander, Desmognathus folkertsi, from the southern Appalachian Mountains

Abstract

To understand patterns of biodiversity and whether populations and species are in decline, the detection and description of cryptic biodiversity are essential. Salamanders are of particular conservation interest because they potentially harbor many undescribed species due to morphological conservatism. The dusky salamanders, genus Desmognathus, are a species-rich group in which morphologically cryptic species are especially common. Using a portion of the mitochondrial genome and amplified fragment length polymorphism (AFLP), we investigated the genetic diversity of the highly endemic, stream-dwelling salamander, Desmognathus folkertsi, across its known range in the Appalachian Mountains. Mitochondrial data revealed three well-supported lineages, one of which consisted of only one specimen; however, AFLP data were not congruent with the mitochondrial data. There was 1.11% uncorrected sequence divergence between the two wellsampled lineages. Desmognathus folkertsi exhibited 4.29% sequence divergence from the closely related D. quadramaculatus. Isolation by distance was found for both the AFLP and mitochondrial data when stream distance, rather than when straight-line (i.e., geographic) distance was used. Although genetic diversity is often partitioned by river drainages in freshwater taxa, we did not observe such a pattern in D. folkertsi. We propose that human-mediated dispersal by bait-bucket release may augment natural gene flow via aquatic dispersal across streams. Because this species was only recently discovered, the full extent of the geographic range is unknown. Therefore, an ecological niche model, using climate variables and the Maxent algorithm, was used to determine whether additional regions may be suitable for the species. The model predicted a small range limited to extreme southwestern North Carolina and extreme northeastern Georgia. We suggest future surveys be focused in these regions.

Conservation genetics of extremely isolated urban populations of the northern dusky salamander (Desmognathus fuscus) in New York City

“…Rissler, Wilbur & Taylor (2004) found little genetic structure between populations of D. monticola in different river drainages, and Croshaw & Glenn (2003) reported two- to four-fold higher heterozygosity in a D. auriculatus population compared to the results presented here. An Appalachian endemic with a highly restricted range, D. folkertsi , also exhibited very little genetic structure across river drainages, although this result may be partly explained by human transport of these salamanders between sites (Wooten et al, 2010). These results indicate that the low levels of genetic variability and substantial genetic structure between D. fuscus populations in NYC are not typical of the genus.…”

Effects of dispersal barriers and geographic distance on the genetic structure of a narrowly distributed frog in a spatially structured landscape

“…For narrowly distributed endemics amphibians, genetic diversity is directly related species persistence in the future (Green, ; Reed & Frankham, ; Allentoft & O'Brien, ; Collins, ). In this study, although O. tormota is a narrowly distributed species, each population still harbored relatively high levels of genetic diversity compared with other narrowly distributed amphibia (Table ), such as the Majorcan midwife toad ( Alytes muletensis ) in the mountainous regions of Majorca, red‐bellied newt ( Taricha rivularis ) in northern California in the United States, Sonoran tiger salamander ( Ambystoma mavortium stebbinsi ) in the San Pedro River of Arizona in the United States, Leora's stream salamander ( A. leorae ) in Iztaccihuatl‐Popocatepetl National Park of Mexico, Fourche Mountain salamander ( Plethodon fourchensis ) in the Ouachita Mountains of the central United States, and dwarf black‐bellied salamander ( Desmognathus folkertsi ) in the United States (Kraaijeveld‐Smit et al ., ; Shepard & Burbrink, ; Wooten, Camp & Rissler, ; Reilly et al ., ; Storfer et al ., ; Sunny et al ., ). In addition, the O. tormota genetic diversity was slightly lower than that of the Shangcheng stout salamander ( Pachyhynobius shangchengensis ) in the Dabie Mountains of eastern China and the Leishan spiny toad ( Leptobrachium leishanense ) in south‐western China, which were described having high genetic diversity (Zhang et al ., ; Pan et al ., ).…”

Ecological niche models in phylogeographic studies: applications, advances and precautions

“…Stockman & Bond ; Wooten et al . ), evaluate adaption to local environmental conditions across populations (Fournier‐Level et al . ; Banta et al .…”