Ambystoma talpoideum (Mole Salamander). Oviposition mode and timing
Explore the source record for details and available documents.
Herpetological Review↗
Geology topics
S.C. Walls
Publications and source records attributed to S.C. Walls.
Widespread occurrence of the amphibian chytrid fungus Batrachochytrium dendrobatidis in the southeastern USA
From 1999 to 2006, we sampled >1200 amphibians for the fungal pathogen Batrachochytnum dendrobatidis (Bd) at 30 sites in the southeastern USA. Using histological techniques or PCR assays, we detected chytrid infection in 10 species of aquatic-breeding amphibians in 6 states. The prevalence of chytrid infection was 17.8% for samples of postmetamorphic amphibians examined using skin swab-PCR assays (n = 202 samples from 12 species at 4 sites). In this subset of samples, anurans had a much higher prevalence of infection than caudates (39.2% vs. 5.5%, respectively). Mean prevalence in ranid frogs was 40.7 %. The only infected salamanders were Notophthalmus viridescens at 3 sites. We found infected amphibians from late winter through late spring and in 1 autumn sample. Although we encountered moribund or dead amphibians at 9 sites, most mortality events were not attributed to Bd. Chytridiomycosis was established as the probable cause of illness or death in fewer than 10 individuals. Our observations suggest a pattern of widespread and subclinical infections. However, because most of the sites in our study were visited only once, we cannot dismiss the possibility that chytridiomycosis is adversely affecting some populations. Furthermore, although there is no evidence of chytrid-associated declines in our region, the presence of this pathogen is cause for concern given global climate change and other stressors. Although presence-absence surveys may still be needed for some taxa, such as bufonids, we recommend that future researchers focus on potential population-level effects at sites where Bd is now known to occur. ?? Inter-Research 2008.
Southeast↗
Occurrence of oral deformities in larval anurans
We quantified deformities in the marginal papillae, tooth rows, and jaw sheaths of tadpoles from 13 population samples representing three families and 11 sites in the southeastern United States. Oral deformities were observed in all samples and in 13.5-98% of the specimens per sample. Batrachochytrium dendrobatidis (chytrid) infections were detected in three samples. There was high variability among samples in the pattern and number of discovered deformities. Pairwise associations between oral structures containing deformities were nonrandom for several populations, especially those with B. dendrobatidis infections or high total numbers of deformities. Comparisons of deformities among samples using multivariate analyses revealed that tadpole samples grouped together by family. Analyses of ordination indicated that three variables, the number of deformities, the number of significant associations among deformity types within populations, and whether populations were infected with B. dendrobatidis, were significantly correlated with the pattern of deformities. Our data indicate that the incidence of oral deformities can be high in natural populations and that phylogeny and B. dendrobatidis infection exert a strong influence on the occurrence and type of oral deformities in tadpoles. ?? by the American Society of Ichthyologists and Herperologists.
Copeia↗
Habitat associations of chorusing anurans in the Lower Mississippi River Alluvial valley
Amphibian populations have declined worldwide. To pursue conservation efforts adequately, land managers need more information concerning amphibian habitat requirements. To address this need, we examined relationships between anurans and habitat characteristics of wetlands in the Lower Mississippi River Alluvial Valley (LMAV). We surveyed chorusing anurans in 31 wetlands in 2000 and 28 wetlands in 2001, and measured microhabitat variables along the shoreline within the week following each survey. We recorded 12 species of anurans during our study. Species richness was significantly lower in 2000 than 2001 ( t -test, P < 0.001) and correlated with an ongoing drought. We found species richness to be significantly greater at lake sites compared to impoundment, swale, and riverine sites (ANOVA, P = 0.002). We used stepwise regression to investigate the wetland types and microhabitat characteristics associated with species richness of chorusing anurans. Microhabitat characteristics associated with species richness included dense herbaceous vegetation and accumulated litter along the shoreline. Individual species showed species-specific habitat associations. The bronze frog, American bullfrog, and northern cricket frog were positively associated with lake sites (Fisher’s Exact Test, P < 0.05), however wetland type did not significantly influence any additional species. Using bivariate correlations, we found that six of the seven most common species had significant associations with microhabitat variables. Overall, our findings support the view that conservation and enhancement of amphibian communities in the LMAV and elsewhere requires a matrix of diverse wetland types and habitat conditions.
Louisiana↗
The effect of community composition on persistence of prey with their predators in an assemblage of pond-breeding amphibians
We examined whether the species composition of a community influences the persistence of larval Ambystoma maculatum in assemblages composed of two larger intraguild predators (A. opacum and A. jeffersonianum) and an alternative prey species (tadpoles of Rana sylvatica). We predicted a priori that A. maculatum would have higher survival in more diverse communities containing alternative species of prey and top predators (A. opacum), the latter of which may lower the abundance of intermediate predators (A. jeffersonianum) via intraguild predation. In a factorial experiment, we manipulated the presence of larval A. opacum, A. jeffersonianum, and R. sylvatica in replicated artificial ponds containing larval A. maculatum. The presence of all three species significantly depressed biomass production in A. maculatum: biomass was highest in ponds lacking the other species and was zero in ponds initially containing all four species. Tadpoles severely reduced the growth of filamentous algae in the ponds. This, in turn, may have affected the abundance of some herbivorous prey of larval salamanders, although this possibility was not tested. The presence of congeneric predators severely restricted the presence in the water column of larval A. maculatum, which otherwise exhibited significant diel patterns of activity in the absence of predators. Together, the presence of tadpoles and a predator-mediated reduction in activity patterns may have limited foraging opportunities for A. maculatum, thus exacerbating the direct impact of predation on survival in this species. These results suggest that diverse assemblages consisting of these particular species may actually inhibit, rather than promote, inclusion of A. maculatum in some communities of pond-breeding amphibians.
Oecologia↗