title: Unexpected rarity of the pathogen Batrachochytrium dendrobatidis in Appalachian Plethodon Salamanders: 1957-2011.
abstract: Widespread population declines in terrestrial Plethodon salamanders occurred by the 1980s throughout the Appalachian Mountains, the center of global salamander diversity, with no evident recovery. We tested the hypothesis that the historic introduction and spread of the pathogenic fungus Batrachochytrium dendrobatidis (Bd) into the eastern US was followed by Plethodon population declines. We expected to detect elevated prevalence of Bd prior to population declines as observed for Central American plethodontids. We tested 1,498 Plethodon salamanders of 12 species (892 museum specimens, 606 wild individuals) for the presence of Bd, and tested 94 of those for Batrachochytrium salamandrivorans (Bs) and for ranavirus. Field samples were collected in 2011 from 48 field sites across a 767 km transect. Historic samples from museum specimens were collected at five sites with the greatest number and longest duration of collection (1957-987), four of which were sampled in the field in 2011. None of the museum specimens were positive for Bd, but four P. cinereus from field surveys were positive. The overall Bd prevalence from 1957-2011 for 12 Plethodon species sampled across a 757 km transect was 0.2% (95% CI 0.1-0.7%). All 94 samples were negative for Bs and ranavirus. We conclude that known amphibian pathogens are unlikely causes for declines in these Plethodon populations. Furthermore, these exceptionally low levels of Bd, in a region known to harbor Bd, may indicate that Plethodon specific traits limit Bd infection.
authors.affiliation: Department of Biology, University of Maryland, College Park, Maryland, United States of America; Center for Conservation and Evolutionary Genetics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States of America.
authors.forename: Carly
authors.initials: C
authors.lastname: Muletz
authors.affiliation: Department of Biology, University of Maryland, College Park, Maryland, United States of America; Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama, United States of America.
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Caruso
authors.affiliation: Center for Conservation and Evolutionary Genetics, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States of America.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Fleischer
authors.affiliation: USGS Patuxent Wildlife Research Center, Smithsonian Institution, National Museum of Natural History, Washington, DC, United States of America.
authors.forename: Roy W
authors.initials: RW
authors.lastname: McDiarmid
authors.affiliation: Department of Biology, University of Maryland, College Park, Maryland, United States of America.
authors.forename: Karen R
authors.initials: KR
authors.lastname: Lips
mesh_terms: D000818:Animals; D001061:Appalachian Region; D008411:Chytridiomycota / Q000302:isolation & purification / Q000472:pathogenicity*; D014562:Caudata / Q000382:microbiology*
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