AbstractsBiology & Animal Science

Assessing Bd prevalence and infection intensity on Jamaica???s frogs in relation to canopy cover in coffee farms

by Jennifer Michelle Brown

Institution: Humboldt State University
Year: 2016
Keywords: Jamaica; Coffee farms; Frogs; Chytrid fungus; Canopy cover
Posted: 02/05/2017
Record ID: 2110186
Full text PDF: http://hdl.handle.net/10211.3/177047


Populations of tropical amphibians have declined primarily from habitat loss and chytridiomycosis, a disease caused by a fungus Batrachochytrium dendrobatidis (Bd). It has been hypothesized that these factors negatively interact, with forest habitat loss reducing prevalence and infection rates of the fungus over wide spatial scales. I examined this hypothesis on twenty-one coffee farms in Jamaica by testing the prediction that Bd prevalence and infection intensity, on two widespread frogs, increases with forest cover surrounding farms and with local canopy cover within each farm. Recent literature suggests fungicides may clear frogs of Bd, so, I also explored the relationship between fungicide use and Bd at the farm scale. At the farm scale, neither Bd prevalence nor intensity was strongly associated with fungicide use or forest cover; Bd was positively associated with elevation for the non-native species Eleutherodactylus johnstonei. Within a farm, infection intensity increased with more shade cover as predicted for E. johnstonei, perhaps due to favorable microclimates. However, infection intensity decreased with shade and leaf litter depth for the native species Eleutherodactylus gossei. Bd prevalence results were inconclusive; prevalence could depend on other factors not addressed (climate, Bd strain, etc.). Although my results were mixed, Bd does appear to be less problematic for some frog species in disturbed habitats with less cover. Frogs that can endure forest loss could find refuge from this disease in human modified habitats, such as coffee farms. Jamaica???s Bd strain is not described, posing challenges for conservation efforts due to variability of Bd epidemiology. Advisors/Committee Members: Johnson, Matthew D..