ARS | Publication request: PESTICIDES AND FROG DECLINES IN THE SIERRA NEVADA MOUNTAINS, CALIFORNIA

Submitted to: The Wildlife Society
Publication Type: Abstract Only
Publication Acceptance Date: August 16, 2005
Publication Date: September 1, 2005
Citation: Cowman, D.F., Sparling, D.W., Fellers, G.M., Bickham, J.W., Mcconnell, L.L., Lacher, T.E. 2005. Pesticides and frog declines in the sierra nevada mountains, california. [abstract]. The Wildlife Society. Madison, Wisconsin, September 2005. p. 38.

Technical Abstract: Previous studies have shown that pesticides from the Central Valley of CA enter the Sierra Nevada ecosystem through aerial deposition in snow and rain, and that surface concentrations of certain pesticides are within an order of magnitude of the 96hr LC50 of amphibians. In order to evaluate the biological effects of these pesticides on Sierran frogs, Pseudacris regilla hatchlings were translocated (with controls in each park) and placed in cages in sites located in Lassen, Yosemite, and Sequoia National Parks. Tadpoles were sampled at 28 days and at metamorphosis. Preliminary results show 1) significant difference (p=0.04) in DNA damage in metamorphs between Lassen (reference site) and the other two parks; 2) greater survivorship to metamorphosis at Lassen; 3) hindlimb deformities (brachymelia) in 25% of animals sampled at Yosemite and 5% at the other two parks; and 4) residues of various pesticides such as chlorphyrifos, endosulfan, and malathion in frog tissues. Discovery of detrimental effects in Pacific chorus frog larvae and metamorphs may help in the evaluation of amphibian declines in the Sierra Nevadas.