Beaver ponds: Influence on peatland ecohydrology

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We know little about the overall changes to wetland and riverine ecosystems throughout North America that were caused by the regional removal of beavers in the 1700s to 1900. This is because nearly all of our hydrological investigations have been conducted in their absence. The beaver population is thought to have re-populated most of its North American habitat over the last 90 years - but at a density of only about 10% of its historical size. What have been the long term effects on wetland-, stream-, watershed- and landscape-scale hydrological processes from beaver extirpation and partial re-population? Have hydrological processes governing the flow regime of rivers and carbon sequestration capacity of wetlands recovered? Are they permanently changed? Not knowing the answers to these fundamental questions is a gaping hole in our understanding of potential water supply risk in the future uncertain climate. This proposal focuses on exploring how beavers influence the interactive pathways between surface and ground waters in peat-forming wetlands located in mountain valley-bottoms. We will use a combination of field observations, hydrological and hydrochemical experiments and hydrological modelling to address general questions such as: Is there focused recharge of alluvial aquifers beneath peatland beaver ponds? Does the amount of water stored in beaver ponds affect aquifer recharge? Do beaver ponds create hydrologic conditions in peatlands conducive for their continued carbon accumulation? The studies will take place in one of the most water-stressed basins in Canada - the Bow River watershed. The work proposed here addresses several of these questions from a fundamental perspective, and will further our understanding of how beaver influence the apportionment of surface water and groundwater in mountain valleys - science needed to inform the development of improved water supply models and wetland management policy. This proposal involves extension training of highly qualified personnel in the form of undergraduates through postdoctoral fellows, preparing them to become the leaders of Canada's future workforce.