Multiple Stressors and Amphibian Population Declines

EPA Grant Number: U915529
Title: Multiple Stressors and Amphibian Population Declines
Investigators: Hatch, Audrey C.
Institution: Oregon State University
EPA Project Officer: Hahn, Intaek
Project Period: August 1, 1999 through August 1, 2002
Project Amount: $101,925
RFA: STAR Graduate Fellowships (1999) RFA Text |  Recipients Lists
Research Category: Fellowship - Life Sciences , Academic Fellowships , Biology/Life Sciences


The overall objective of this research project is to investigate the impacts of multiple stressors on developing amphibians in the Pacific Northwest. Specifically, the research focuses on interactions among ultraviolet light (UV), nitrate fertilizer, and acidification in a laboratory experiment; UV and nitrate fertilizer in an outdoor microcosm experiment; and UV and oil pollution in an outdoor microcosm experiment. All of these environmental stressors are relevant to ephemeral ponds in the Pacific Northwest, where many species of amphibians breed.


The experimental approach of this research integrates fully factorial laboratory and outdoor microcosm experiments with field monitoring and enclosure experiments. The investigator will work with several species that breed in western Oregon: the long-toed salamander, Ambystoma macrodactylum; the Northwestern salamander, Ambystoma gracile; the Cascades frog, Rana cascadae; the red-legged frog, Rana aurora; the Western toad, Bufo boreas; and the Pacific treefrog, Hyla regilla. Biological endpoints measured include survival, growth, development time, and predator-prey interactions. The abiotic factors of interest will be monitored in the field.

Expected Results:

A better understanding of the combined effects of several environmental factors (i.e., nitrate, UV light, and acidification) on the amphibian population in the Pacific Northwest.

Supplemental Keywords:

amphibian population decline, multiple stressors, UV radiation, nitrogen fertilizer, sublethal effects, Pacific Northwest, Oregon, OR, RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, amphibians, Environmental Monitoring, Pacific Northwest, Ecological Risk Assessment, Ecology and Ecosystems, Biology, frogs, population decline, multiple stressors, salamanders, field monitoring, nitrate fertilizer, amphibian bioindicator

Progress and Final Reports:

  • 2000
  • 2001
  • Final