Impacts of Beaver Systems on Lateral and Downstream Hydrological Connectivity

加拿大的许多水道都是标志性的生态系统工程师--海狸的家园。我研究海狸如何“设计”水道，以便为整体水资源管理和海狸管理提供信息。海狸最出名的是建造水坝和砍伐树木。但是，他们也挖掘了广泛的运河网络，用来获取和运输木本食物。虽然人们对河狸水坝和水渠建设的基本情况有所了解，但令人惊讶的是，我们对河狸水坝如何调节水的储存和流动路径知之甚少，尤其是在整个海狸水坝网络的规模上，对海狸水渠在收集和向溪流输送水方面的作用几乎一无所知。因此，我未来六年的计划是让我和我的学生们加深对海狸(水坝和运河)建造的物理结构的理解，以及它们沿水道的空间安排如何影响水循环。我们的研究将需要在加拿大落基山脉的水道进行广泛的实地工作，这是加拿大西部大部分地区的主要淡水供应。在第一项研究中，我们将使用无人机拍摄高分辨率的河狸大坝图像，并开发新的计算机视觉技术，以建立以前无法达到的规模的河狸大坝的数字模型。我们将使用数字模型来了解河狸大坝复杂的结构如何调节它们的回水效应(蓄水)和渗透性。在研究二中，我们将使用跟踪摄像机来获得水流通过网络中每个河狸坝的水流路径的时间推移，即大坝的水流状态。大坝流动状态的时间推移将与地表和浅层地下水测量相结合，以确定不同流动状态的河狸坝如何影响下游流动的水量与返回大气的水量或储存在浅层地下水中的水量。在研究三中，我们将使用跟踪相机和水流测量相结合的方法来确定河狸渠道如何以及何时收集水并将其输送到主流道。总体而言，这项研究计划将开发创新工具，以表征海狸大坝的内部工作原理，并揭示海狸建造的结构网络如何从根本上改变河流走廊的内部管道。拟议工作的一个关键应用是，它处于独特的位置，可以揭示有助于缓解加拿大低北极冻土带地区地表水和热岩溶发育变化的重要和基础信息，因为由于气候变化，海狸继续侵入这些地区。拟议的研究计划将为11名学生和1名博士后创造丰富的培训经验，为他们作为野外生态水文学家的职业生涯做好准备，准备解决加拿大正在出现的水危机，并创新以恢复加拿大退化的水道的健康和功能。

Many of Canada's waterways are home to the beaver, an iconic ecosystem engineer. I study how beavers `engineer' waterways so as to inform holistic water resources management and beaver management. Beavers are best known for building dams and cutting trees. But, they also excavate extensive networks of canals which they use for accessing and transporting woody foodstuffs. While the basics of beaver dam and canal construction are known, we know surprisingly little about how beaver dams regulate water storage and flowpaths, especially at the scale of entire beaver dam networks, and almost nothing about the role of beaver canals in collecting and conveying water to streams. Hence, my plan for the next six years is for my students and I to advance our understanding of the physical structures built by beavers (dams and canals) and how their spatial arrangement along waterways affects water cycling. Our studies will require extensive field work in waterways located in the Canadian Rocky Mountains, which is the primary supply of freshwater to most of western Canada. In study one we will use drones to take high-resolution images of beaver dams and develop novel computer vision techniques to build digital models of them at a scale previously unattainable. We will use the digital models to learn about how the structural intricacies of beaver dams regulate their backwater effects (ponding) and permeability. In study two we will use trail cameras to get a time-lapse of the flow path that streamflow takes past each beaver dam in a network, i.e. the dam flow state. The time-lapses of dam flow state will be coupled with surface and shallow groundwater measurements to determine how beaver dams of different flow states affect the amount of water that travels downstream vs. returns to the atmosphere or becomes stored in shallow groundwater. In study three we will use a combination of trail cameras and streamflow measurements to determine how and when beaver canals collect water and convey it to the main stream channel. Overall, this program of research will develop innovative tools to characterize the inner workings of beaver dams and expose how networks of beaver-built structures radically change the internal plumbing of river corridors. One key application of the proposed work is that it is uniquely positioned to uncover vital and foundational information useful to mitigating changes in surface water and thermokarst development that are occurring in Canada's low arctic tundra region as beavers continue to encroach into these areas owing to climate change. The proposed research program will create a rich training experience for 11 students and one postdoctoral fellow, preparing them for careers as field ecohydrologists ready to solve Canada's emerging water crisis and innovate to restore the health and function of waterways in Canada that are degraded.