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David K. Skelly
Yale University
School of Forestry & Environmental Studies
370 Prospect Street
New Haven, CT 06511 USA

Yale FES



Conservation & Applied Ecology

Amphibian declines and developmental abnormalities:  It has been over a decade since widespread declines and extinctions of amphibians were first reported.  Nevertheless, ecologists still have little concrete idea why amphibian populations have declined and, in many cases, gone extinct.  We are using long term observational data in conjunction with field experiments to unravel the causes for amphibian population extinctions.

We are also interested in the mechanisms leading to outbreaks of amphibian deformities.  Ongoing work in Vermont is aimed at understanding the causes for limb abnormalities in leopard frogs in the Lake Champlain basin. The leading suspected cause of deformities involves infection by Ribeiroia ondatrae, a trematode.  Exhaustive sampling in Vermont has failed to turn up any evidence of Ribeiroia demonstrating that high frequencies of deformities can occur over a large area in the absence of infection by Ribeiroia ondatrae.  These findings leave open the issue of what is causing deformities in Vermont and other regions where Ribeiroia is absent.  One possibility, exposure to chemical pollutants, is supported by an association between the risk of deformities and the proximity to agricultural sites. 

Interactions between human and non-human components of watersheds:  This project is a collaborative effort among several faculty at the School of Forestry & Environmental Studies.  We have been working to document the associations between patterns of abundance and distribution in a number of non-human taxa, physicochemical conditions, and patterns of distribution, behavior, and attitudes among human residents.  The study has been conducted in 18 watersheds of ca. 1000 ha spread across the greater New Haven region.  We have found that human attitudes, beliefs, and behavior are strongly linked to landscape structure, which in turn, is a strong predictor of the biological condition of stream watersheds. 

Habitat Conservation Planning:  Graduate Students from the School of Forestry & Environmental Studies participated in a working group on Habitat Conservation Plans (HCPs) at the National Center for Ecological Analysis and Synthesis in Santa Barbara.  Our task was to complete a comprehensive evaluation of the content and quality of HCPs developed to protect endangered species on non-Federal land.  The analysis involved faculty and students from 8 different Universities around the U.S.  We reviewed most of the 200-odd plans in existence at the time the project began and looked at 43 of those plans in much greater depth.  Among the more critical findings was the determination that use of natural history information varies greatly and that relevant ecological theory has been applied sporadically.  We concluded our report with a set of recommendations to improve the development and implementation of HCPs that have, in large measure, been adopted by the U. S. Fish and Wildlife Service.


Vermont farmpond


Skelly, D. K. 2001. Distributions of pond-breeding anurans: an overview of mechanisms. Israel Journal of Zoology 47:313-332. [Special Issue on the Ecology of Temporary Pools]  Link

Skelly, D. K., K. L. Yurewicz, E. E. Werner, and R. A. Relyea. 2003. Estimating decline and distributional change in amphibians. Conservation Biology 17:744-751.  Link

Taylor, B., D. K. Skelly, L. K. Demarchis, M. D. Slade, D. Galusha, and P. M. Rabinowitz. 2005. Proximity to pollution sources and risk of amphibian limb malformation. Environmental Health Perspectives 113:1497-1501.  Link

Urban, M. C., D. K. Skelly, D. Burchsted, W. Price, and S. Lowry. 2006. Stream communities across a rural-urban landscape gradient. Diversity and Distributions 12:337-350.  Link   Faculty of 1000 Review

Kareiva, P., D. Skelly, and M. Ruckelshaus. 1997. Reevaluating the use of models to predict the consequences of habitat loss and fragmentation. Pages 156 to 166 in S. T. A. Pickett, R. S. Ostfeld, M. Shachak, and G. E. Likens (Eds.) Enhancing the ecological basis of conservation: heterogeneity, ecosystem function, and biodiversity. Chapman and Hall, New York.

Deformed leopard frog metamorph