New publication: high prevalence of chytrid fungus in southern Oklahoma

Marhanka.etal.2017_Fig1As part of a collaborative effort with the Siler Lab at the University of Oklahoma, I have been involved in efforts to help screen amphibian skin swabs for the pathogenic fungus, Batrachochytrium dendrobatidis (Bd). This manuscript presents the results of pathogen surveys conducted during 2015 in eight counties in southeastern Oklahoma. Overall Bd prevalence was 64.8% and all families swabbed and 15 (of the 18) species of amphibians had individuals that were Bd+. Given the high Bd prevalence and widespread occurrence of Bd across species and sites, this pathogen has the potential to have profound negative impacts on native Oklahoma amphibians.

Marhanka EC*, Watters JL, Huron NA, McMillin SL*, Winfrey CC*, Curtis DJ, Davis DR, Farkas JK, Kerby JL, Siler CD. 2017. Detection of high prevalence of Batrachochytrium dendrobatidis in amphibians from southern Oklahoma, USA. Herpetological Review 48:70–74. [PDF]

Funding awarded to survey for state-monitored​ species

I was recently awarded funding by Prairie Biotic Research, Inc. to survey four remnant prairies sites in southeastern South Dakota for state-monitored species of amphibians and reptiles. The highest species diversity of amphibians and reptiles is in this corner of South Dakota and many state-monitored species are expected to occur in this region, though recent occurrence records are lacking for many species. These state-monitored species include Eastern Hog-nosed Snake, Lined Snake, Ring-necked Snake, Western Foxsnake, Plains Leopard Frog, Cope’s Gray Treefrog, and Blanchard’s Cricket Frog. With this funding, I hope to add additional occurrence records for these species and others, generate critically important voucher specimens, and highlight the importance of prairie habitats on a landscape that is dominated by row crop agriculture. Data from this project will be added to the website: Amphibians and Reptiles of South Dakota.

Grant Title: Amphibian and reptile surveys in remnant prairies in southeastern South Dakota, with special emphasis on state-monitored species

New publication: antipredator behavior of Barton Springs Salamanders in response to aquatic invertebrates

Davis.etal.2017_Figure2The Barton Springs Salamander, Eurycea sosorum, is a fully aquatic salamander found in Barton Springs in Texas, USA, and has benefited from habitat restoration efforts. While important to improve overall habitat quality for this imperiled species, current management and restoration practices may also inadvertently increase the abundance of non-target organisms such as predatory invertebrates. Fish represent major predators of this species, but little is known about the role of invertebrates as potential predators. It is important to understand the role of these aquatic invertebrates as predators of E. sosorum, especially if habitat restoration also increases predator abundance. Using adult, predator-naive salamanders, we examined the antipredator response of E. sosorum to chemical cues from the following treatments: crayfish, dragonfly larvae, snails, and water. Salamanders decreased activity (antipredator behavior) only in response to the crayfish treatment. The responses to dragonfly larvae, snails, and water did not differ, suggesting that dragonfly larvae are not perceived as predators by these salamanders. Our study provides preliminary evidence suggesting that habitat restoration has unexpectedly increased crayfish abundance, which in turn may negatively affect E. sosorum, and that future management strategies should consider crayfish removal if salamander abundances decline with increasing crayfish abundance.

Davis DR, DeSantis DL, Gabor CR. 2017. Antipredator behavior of the Barton Springs Salamander (Eurycea sosorum) in response to aquatic invertebrates: potential consequences from habitat restoration. Hydrobiologia 795:129–137. [PDF]


New South Dakota resource on amphibians and reptiles

sdherpsA new website on the Amphibians and Reptiles of South Dakota is now live. This website contains species accounts for all 45 species found in the state and has distribution maps generated from data from over 11,400 specimens (voucher specimens and photographs). This website is a collaboration with HerpMapper in order to educate the public on amphibian and reptile conservation as well as encourage citizen science reporting of species observations.

New publication: a new species of Pseudogekko from the central Philippines

romblonpseudogekkoWe describe a new species of lizard in the genus Pseudogekko from Sibuyan and Tablas islands in the Romblon Island Group of the central Philippines. The new species is diagnosed from other Philippine Pseudogekko by body size and shape, color pattern, and multiple differences in scale characteristics. Pseudogekko isapa sp. nov. has been collected only twice from leaves of shrubs in forested habitat on Sibuyan and Tablas islands. The distinctive new species of false gecko is undoubtedly endemic to this single, isolated island group. The fact that populations of such a distinctive new species of Pseudogekko has escaped notice of herpetologists on the reasonably well-studied and largely protected Sibuyan Island further emphasizes the secretive and forest-dependent habits of Philippine false geckos. These characteristics of their behavior and natural history render them difficult to study and challenge biologists’ efforts to accurately assess their conservation status.

Siler CD, Davis DR, Diesmos AC, Guinto F, Whitsett C, Brown RM. 2016. A new species of Pseudogekko (Squamata: Gekkonidae) from the Romblon Island Group, Central Philippines. Zootaxa 4139:248–260.