Beaver ponds: Influence on peatland ecohydrology

我们对整个北美湿地和河流生态系统的总体变化知之甚少，这些变化是由18世纪至1900年海狸的区域性迁移造成的。这是因为我们几乎所有的水文调查都是在他们缺席的情况下进行的。在过去的90年里，海狸的数量被认为已经重新填充了北美的大部分栖息地，但密度只有其历史规模的10%左右。海狸灭绝和部分重新种群对湿地、溪流、流域和河流尺度水文过程的长期影响是什么？控制河流流态的水文过程和湿地固碳能力是否得到恢复？它们会永久改变吗？不知道这些基本问题的答案是我们对未来不确定气候下潜在供水风险的理解中的一个巨大漏洞。本计画的重点是探讨海狸如何影响位于山谷底部的泥炭湿地地表与地下沃茨之间的互动路径。我们将使用相结合的实地观察，水文和水化学实验和水文建模，以解决一般性的问题，如：有集中的泥炭地海狸池塘下的冲积含水层的补给？海狸池塘中储存的水量会影响含水层的补给吗？海狸池塘是否在泥炭地创造了有利于其持续碳积累的水文条件？这些研究将在加拿大水资源最紧张的流域之一--弓河流域进行。这里提出的工作从根本上解决了这些问题中的几个，并将进一步了解海狸如何影响山区山谷地表水和地下水的分配-科学需要告知改进的供水模型和湿地管理政策的发展。这项建议涉及对高素质人员进行从本科到博士后的扩展培训，使他们成为加拿大未来劳动力的领导者。

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.