Do Frogs Still Get Their Kicks On Route 66. A Transcontinental Transect For Amphibian Chytrid Fungus (Batrachochytrium Dendrobatidis) Infection On U.S. Department Of Defense Installations

摘要

One fifth of the world's amphibians now face extinction. A major factor in these declines has been the spread of infection by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), which, as a disease (chytridiomycosis) has been devastating amphibian populations globally. To better understand the spatial and temporal scales of infection by this pathogen, we conducted a transcontinental transect for the presence of Bd. United States Department of Defense (DoD) installations were sampled from west to east along U.S. Highway 66 from California into central Illinois, and continuing eastward from there across to the Atlantic Seaboard along U.S. Interstate 64 (in sum from Camp Pendleton in California to Naval Air Station Oceana in Virginia, between 33 deg and 39 deg N latitude). We sampled each installation across the 2009 warm season using standardized collection and analytical techniques. This study represents the most geographically extensive survey for Bd conducted to date. Half of the amphibian species sampled (15/30) tested positive for Bd. There was a strong spatial component to our dataset; the 10 eastern temperate DoD installations had higher rates of Bd infection (18.9%) than the five bases situated in the more arid west (4.8%). There was also a strong temporal (seasonal) component to our dataset. In total, 78.5% of all positive samples were collected in the first (spring/early-summer) sampling period. These data support the conclusion that Bd is now widespread, from coast to coast, and argue that Bd, a pathogen that was once likely epidemic, can today be considered endemic, extending transcontinentally across much of North America.