Amphibians as indicators of wetland quality in wetlands formed from oil sands effluent

Abstract

AbstractFort McMurray, Alberta, Canada, is home to the largest oil sands mining operation in the world. Two of the companies currently mining the oil sands hope to use wetlands formed from oil sands effluent as part of their reclamation strategy required at mine closure. To evaluate the ability of these created wetlands to sustain amphibians, one population of Bufo boreas tadpoles and three different populations of Rana sylvatica tadpoles were exposed to oil sands process‐affected water representative of a range of effluents expected to occur on the oil sands lease site at mine closure. Endpoints used to assess the response of the tadpoles to the process‐affected waters included survival, growth, rate of development, and frequency of physical deformities. Bufo boreas held in process‐affected waters displayed significantly reduced growth and prolonged developmental time (days to metamorphosis) as compared to those held in reference waters. The response of the three separate populations of R. sylvatica were population dependent. Two of the three populations responded similarly, demonstrating decreased survival and significantly reduced rates of growth when held in process‐affected waters as compared to reference waters; the third was highly sensitive, displaying no growth and extremely poor survival in all exposures, suggesting different tolerances to the process‐affected waters among different R. sylvatica tadpole populations. Amphibians such as B. boreas and R. sylvatica were sensitive indicators of effluent quality. Based on the effluents used in this study, wetlands formed from oil sands effluent will not support viable amphibian populations.