A Contradiction in Genes: Phylogeography of the Black Mountain Salamander (Desmognathus welteri Barbour 1950)
The development of modern molecular techniques has led to the discovery of previously unsuspected levels of genetic variation, particularly within taxa characterized by morphological conservatism and/or rampant homoplasy. The lungless-salamander family Plethodontidae is characterized by both, and molecular-based investigations of phylogeography have uncovered a number of cryptic lineages, including many that have subsequently been described as species. An important phylogeographic tool continues to be the sequencing of mitochondrial DNA (mtDNA), which is especially useful for analyses at the specific and generic levels because of its rapid rate of nucleotide substitution relative to nuclear genes (nDNA). MtDNA has been criticized as a phylogenetic marker, however, because it represents only a small fraction of an organisms’ genome and is inherited strictly maternally. In fact, recent studies have indicated that mitochondrial-based and nuclear-based conclusions regarding phylogeny may sharply disagree. We used both mitochondrial (ND2, COI, 12S) and independent nuclear (introns of ILF3 and GAPD) genes to investigate the phylogeography of the Black Mountain Salamander (Desmognathus welteri Barbour 1950). We found that both nuclear introns exhibited considerable genetic structure among populations but that mtDNA sequences showed hardly any variation across the entire geographic range. The most parsimonious explanation is that the mitochondrial genome has undergone a relatively recent selective sweep in this species. Our results underscore the need to use caution when drawing phylogenetic conclusions from mtDNA sequences.
Automated recordings of anuran mating calls were used as a non-disruptive technique to determine species richness on an urban campus. Automated recording loggers were deployed at two pond sites and a stream site at Georgia Gwinnett College, Lawrenceville, GA in 2013. Loggers recorded sounds and temperatures between 8 p.m. and 2 a.m. It was hypothesized that in addition to species richness, the loggers may indicate specific mating call behaviors, such as timing, frequency, and duration of the calls. The pond habitats had the most abundant frog calls and included American bullfrogs (Lithobates catesbeiana) and green frogs (Lithobates clamitans). The stream site had the highest anuran species richness, including the bird-voiced tree frog (Hyla avivoca) and other tree frogs (Hyla chrysoscelis, H. veriscolor, and H.cinerea). Gray tree frogs (Hyla versicolor/chrysoscelis) were recorded only during the last week of May and first two weeks of June at all sampling sites. These species were specific in the times and dates of calling, particularly in areas with large predatory anurans, such as the bullfrog. This behavior may be a consequence of predator avoidance and/or competition with other calling anuran species.
School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA
196 • Timothy E. Baldwin1, Yong Wang2, Callie J. Schweitzer3
The Influence of Forest Management Practices on Amphibian Accessibility, Larval Performance, and Adult Choice Within the Cumberland Plateau in Grundy County, Tennessee
The purpose of this project was to assess the influence that forest disturbance has on pool breeding amphibian reproductive success. This experimental study was executed within Burrows Cove in Grundy County, Tennessee. A split-split plot design was used to examine the effect forest treatment (main factor), distance to forest edge (sub-factor), and variation in amount of light reaching the pools (split-split factor) on amphibian breeding parameters. The forest treatments included: control with gaps (five replications), shelterwood (four replications), and an oak shelterwood (five replications). Three artifical ponds were established at each of the three distance categories (ten meters, fifty meters, and one hundred meters) in each of the forest stands. Three pools at each distance were randomly assigned to allow thirty percent, fifty percent, and eighty four percent of the light relative to control stands to reach the pools using light screens. Artifical pools were monitored over two breeding seasons. A repeated measures analysis of variance (SPSS 19.0) was used to compare amphibian species abundance across different treatments, along the distance gradient, among the different canopy treatments, and between the two breeding seasons. Multiple linear regression (SPSS 19.0) was used to compare the local and stand level environmental variables to amphibian species abundance. In the field experiment, eight amphibian species were identified, 4,324 larval amphibians were counted, and 146 (5,776 embryos) amphibian egg masses were tallied. Larval amphibian abundance was higher within the shelterwood treatment and the thirty percent arrays.
1Southern Research Station, USDA Forest Service, Oxford, MS; 2 Dept of Biological and Environmental Sciences, Alabama A&M University, Normal, AL; 3 Southern Research Station, USDA Forest Service, Huntsville, AL
197 • Thomas P. Wilson1, Paul-Erik Bakland1, Nyssa Hunt1, Simone Madsen1, Preston Prigmore1, Robert Altonen1, Sarah Bohr1, Brittany Bird1, Tabitha M. Wilson2
