Reports of declines in amphibian populations, specifically the well-publicized studies of extensive embryo mortality from ultraviolet B radiation and metamorph deformities from exposure to bioactive retinoids, has resulted in frogs and other amphibians being labeled as present-day "canaries in coal mines" regarding environmental pollutants. Clearly, amphibians exhibit numerous traits that promise to make them suitable as bioindicators of wetland stress. Specifically, their 1) breeding occurs in wetlands that are experiencing anthropogenic alterations in hydrology and water quality, 2) systematics and identification to species level for all life stages are relatively well known, 3) general ecology and life history is virtually established, 4) distribution, abundance and health can readily be ascertained during spawning, embryonic development, metamorphosis and as adults, and 6) descriptive and quantitative sampling methods are becoming increasingly available.In contrast, amphibians' wide tolerances to sub-optimum wetland conditions and dirth of information on indicator strength to abiotic (organics, metals, general water chemistry) and biotic (competition, predation and symbiosis) factors may limit their immediate, widespread and generalized use as bioindicators of wetland stress until additional ecological information is known.
Consequently there are a wide variety of challenges to utilizing amphibians as bioindicators and specifically in developing a metric that will discriminate along a continuum between least to most impaired wetlands.
18) Comments/Requests:
PNW 98 Session - Full Abstracts