Impact/Purpose:

GENERIC RARE OBJECTIVE: The Regional Applied Research Effort (RARE) provides the Regions with a mechanism to address near term research needs through an ORD Laboratory/Center. Any applied research project that a Region identifies and that an ORD laboratory has the expertise to carry out will be considered if the three following conditions are met: 1) projects must be funded through an ORD Laboratory or Center, 2) the project must fall within with defined mission of the selected ORD Laboratory/Center, and 3) proposals must be research-oriented.

Description:

The goals of this project were 1) to gather field and laboratory information that will further our knowledge regarding the role of biologically active agents (including current use agricultural pesticides) on the occurrence of northern leopard frog (Rana pipiens) abnormalities in the Lake Champlain Basin, and expand current data bases documenting the status and variability of morphological abnormalities among northern leopard frog populations at historically monitored sites in the Lake Champlain Basin. This project included a series of coordinated field and laboratory tasks that: characterized the occurrence of northern leopard frog (NLF) abnormalities in both sub-samples and broad population level samples over time; evaluated the potential of site sediment and water to induce limb abnormalities of a type and at a frequency of occurrence observed in the field through laboratory developmental limb bud assays; investigated potential causal agents through field developmental observations, and chemical characterization of water and sediment from test sites. A minimum of five sites in Vermont supporting breeding populations of the northern leopard frog, Rana pipiens, and showing a range of gross hind limb abnormality incidence indicative of impact and reference conditions were selected for evaluation. Breeding and development of R. pipiens were monitored at all sites through adult metamorphosis. Representative sub-samples of developing and metamorphosed northern leopard frogs were collected and examined for the purpose of determining abnormality incidence rate and the relationship of observed anomalies to selected physical characteristics, including evidence of physical trauma. Intensive monitoring of amphibian populations was conducted at one site to describe multi-species population-level abnormality incidence. Potential pesticide contamination at all sites will be evaluated by analyzing representative sediment and water samples for a range of agricultural pesticides and metabolites in common use throughout the Lake Champlain Basin. Limb bud assays were conducted using both Xenopus laevis and Rana pipiens in order to evaluate the test response relationships between the two species and to evaluate endpoints relevant to Lake Champlain findings, specifically hind leg reduction malformations.

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