Habitat Effects on Chytridiomycosis Infection in The Critically Endangered Agalychnis Moreletii.

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Lawson, Tyler
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Recent times have seen amphibian populations around the world vanishing at an alarming rate due to factors such as habitat destruction, pollution, and infectious diseases. During the summer of 2008 I examined how factors such as these are affecting the critically endangered black-eyed treefrog, Agalychnis moreletii (Hylidae), in shaded coffee plantations, technified coffee plantations, and natural areas in the country of El Salvador. Nocturnal surveys of calling adult males were conducted to estimate relative abundance. Larvae were screened with a hand lends to look for indications of infection with Batrachochytrium dendrobatidis, a lethal amphibian fungus that causes chytridiomycosis. Subsamples of inspected tadpoles were preserved for PCR analysis to determine the effectiveness of hand lens screening for presence of B. dendrobatidis and to determine if there was a difference in B. dendrobatidis prevalence among habitats. Results showed that only two of thirteen sites sampled for B. dendrobatidis were heavily infected. Statistical analysis indicated that the odds of infection were lower for technified plantations than for non-technified sites. However, these results were influenced by the two heavily infected sites. Nocturnal surveys showed weak evidence that A. moreletii populations in shaded plantations are larger than technified plantations and natural areas. Hand lens analysis of external mouthpart abnormalities was found to predict presence of chytrid infection with relatively good success across a large spatial scale. Intriguing questions remain as to the effects of habitat on chytrid infection. Future studies should investigate if chytridiomycosis is as critical a factor in decline of A. moreletii as previously thought.
Ecology;Animal sciences; Environmental science; El Salvador; Amphibians;