The Effects of Mining Effluent on Amphibian Survivorship

Abstract

Amphibian populations and species diversity are declining at an alarming rate all over the world. In Montana, mining has been suggested as the culprit for this decline. I continued Meis’s (1999) study at the Upper Frohner Meadow site after a settling pond had been introduced reduce the heavy metal contamination. I looked for increased survivorship between the two years, using western toad tadpoles (Bufo boreas), and determined differences in hardiness by comparing spotted frog tadpoles (Rana levitrius), both of which were contained in enclosures in groups of 50. The results showed a 39.4% increase in toad survivorship since the use of a settling pond. The frogs had a 57.6% higher average survivorship than the toads. The consequences of this research suggest settling ponds are effective tools for reducing or eliminating heavy metal contamination, therefore, increasing water quality. It also showed spotted frogs could tolerate the contamination better than western toads and would be most likely to repopulate a bioreclaimated site.