Pesticides and Amphibian Pathogens in Natural and Created Wetlands in the New Jersey Pinelands

Science Center Objects

The New Jersey Water Science Center in collaboration with the New Jersey Pinelands Commission and Montclair University, conducted a 4 year study to assess the functional equivalency of ponds and stormwater basins in the New Jersey Pinelands by comparing indicators of hydrologic condition, water quality (including pesticides) and biological metrics (amphibian pathogens).

Swabbing a Wood frog tadpole in the Pinelands

Scientist swabbing a wood frog tadpole for the fungal pathogen, Batrachochytrium dendrobatidis (Bd)

(Credit: John Bunnell, NJ Pinelands Commission. Public domain.)

The loss and degradation of habitat, exposure pesticides and diseases are among several notable stressors to amphibian populations worldwide. Land-use changes such as increased development or agricultural production may not destroy habitat but usually includes alterations such as the application of chemicals that can threaten native species like amphibians. Ponds and stormwater basins provide habitat necessary for wetland-dependent plants and animals, especially in altered or human-dominated landscapes where natural wetlands may be degraded or eliminated.  In urban landscapes, habitat loss and a decrease in habitat quality are two factors playing a role in amphibian population declines. Amphibian populations and community structure dynamics have been studied extensively in “natural” habitats in the Northeast, but currently, this is the first study to evaluate the exposure of amphibians to pesticides and pathogens in urban stormwater basins in NJ.


Pesticide typically don’t cause death but instead can cause sub-lethal effects such as reduced reproduction, growth and development. Exposure to pesticides can also have positive or negative effects on transmission of diseases, infection rates and susceptibility. Two emergent amphibian diseases observed frequently in the Northeast include, the chytrid fungus, Batrachochytrium dendrobatidis (Bd) and Ranavirus a highly virulent pathogen both of which have been implicated in mortality events worldwide. The microbes living on the skin of amphibians provide protection against diseases like Bd.  There is very little information available on how pesticides and other contaminants effect the skin microbial community and their ability to ward off diseases.


This project was designed to determine the pesticide and pathogens present in wetlands throughout the New Jersey Pinelands in both ponds and stormwater basins.


Map of the Pinelands sampling locations

Map of the Pinelands sampling locations

(Public domain.)


  • 24 wetlands were selected from an inventory of natural ponds, excavated ponds and stormwater basins mapped by the Pinelands Commission as part of a larger study (link to EPA report when we have it).


  • 4 reference (minimum land-use impact) and 4 degraded (maximum land-use impact) were selected from a pool of natural ponds, excavated ponds and stormwater basins.


  • Water, bed-sediment, larval frog food (algae) and larval frogs were collected once from each wetland and analyzed for over 100 pesticides.


  • Larval frogs were also sampled for two emergent pathogens (the chytrid fungus, Batrachochytrium dendrobatidis (Bd) and Ranavirus).








New Jersey Pinelands Commission Report: Natural and Created Wetlands Study


USGS Project Team: Jon Cohl, Kristin Romanok and Brianna Williams



   New Jersey Pinelands Commission

   Environmental Protection Agency Region 2

   Montclair University

   USGS Amphibian Research and Monitoring Initiative