On the Need for Water Quality Criteria to Protect Amphibian Populations

R. Boyer

C.E. Grue

Abstract

	Even though amphibian populations have apparently declined in many 
parts of the world and they are thought to be reliable indicators of 
environmental quality, past ecological and toxicological studies have often 
neglected amphibians. Changes in water quality resulting from habitat loss/
degradation and pollution may be major factors in amphibian population 
declines. Unfortunately, water quality criteria for amphibians are lacking, 
and it is not known whether existing criteria for other aquatic biota offer 
protection for the amphibian species. Our recent research to assess water 
quality in relation to frogs at the Klamath Basin National Wildlife Refuges 
revealed that exposure of Xenopus laevis embryos to Refuge water samples 
resulted in mortality or malformation. High water temperatures, low 
dissolved oxygen (D.O.), elevated pH, and high un-ionized ammonia (NH3) levels 
characterized the Refuge water. We present our proposal for research to 
develop water quality criteria for naturally occurring frog species on the 
Refuges and in the Klamath Basin by determining the effects and interactions 
of pH, water temperature, un-ionized ammonia, D.O., and selected 
agricultural chemicals on frog embryo development and survival in Xenopus 
and other frog species. These criteria may well apply to other Western 
agroecosystems, or other regional ecosystems with similar water conditions.