Determining forest disturbance thresholds for managing cumulative hydrological impacts

随着森林干扰和气候变化的加剧，森林干扰对水文的影响及其对供水和其他水生功能的影响日益受到关注。然而，这项研究的大部分是在小流域（500平方公里）进行的，因为森林干扰往往在空间和时间上累积发生，其水文影响是累积的。在我的NSERC发现赠款的支持下，我建立了一个名为"大流域的森林干扰和水文"的研究计划，我们成功地开发了一种称为修正双质量曲线（MDMC）的方法，用于量化任何单个流域森林干扰造成的累积水文效应。使用这种方法和其他统计技术，我们研究了关键的研究问题，如累积水文效应，森林干扰和气候之间的相互作用，以及嵌套流域水文影响的空间尺度。我们的研究结果已发表在高影响力的期刊上（例如，水资源研究，水文学杂志，全球变化生物学，自然通讯）。我们的进展导致了一个重要的研究问题：什么是森林干扰阈值超过显着累积水文影响可以检测到？令我们惊讶的是，鉴于其在可持续发展方面的重要性，对这一主题的研究非常有限，主要是由于一些方法上的挑战。研究这一问题可以大大促进流域科学的发展，促进流域的可持续发展。在这个原始的和创新的研究，50个流域从内部的不列颠哥伦比亚省（BC）将被选中，其中几个统计技术，包括MDMC将被应用到确定森林干扰阈值为每个流域单独。短期目标（2021 - 2026年）是：（1）定量确定年平均流量的森林干扰阈值;（2）确定森林干扰阈值高流量和低流量;（3）上述所有50个流域的结果，以评估气候和流域特性是否也控制这些阈值。我的长期目标是在更广泛的背景下评估生态阈值或临界点和恢复力，考虑更多的生态过程，并扩大空间范围，在更大的空间尺度上研究森林干扰阈值。不列颠哥伦比亚省内陆地区是这项研究的理想区域，因为有许多测量流域，水文，气候和森林干扰的长期历史数据。该研究将为BC管理森林干扰以保护水生功能提供重要和及时的信息。这将有助于制定森林干扰阈值，以有效管理累积水文风险。最后，本项目将培养2名HQP和5名本科生。

The impacts of forest disturbance on hydrology have been receiving growing attention due to increasing forest disturbance and climate change, and their effects on water supply and other aquatic functions. However, the majority of this research has been conducted on small watersheds (500 km2), as forest disturbance often occurs cumulatively over space and time, its hydrological impacts are cumulative. With support from my NSERC Discovery Grants, I established a research program entitled "Forest Disturbance and Hydrology in Large Watersheds" where we have successfully developed a method referred to as modified double mass curve (MDMC) for quantifying the cumulative hydrological effects caused by forest disturbance in any individual watershed. Using this method and other statistical techniques, we have studied critical research questions such as cumulative hydrological effects, interactions between forest disturbance and climate, and spatial scaling of hydrological impacts across nested watersheds. Our results have been published in high-impact journals (e.g., Water Resources Research, Journal of Hydrology, Global Change Biology, Nature Communications). Our progress has led to an important research question: what are forest disturbance thresholds over which significantly cumulative hydrological impacts can be detected? To our surprise, there is very limited research on this topic given its significance in sustainability, mainly due to several methodological challenges. Answering this question can greatly advance watershed science and promote watershed sustainability. In this original and innovative study, 50 watersheds from the interior of British Columbia (BC) will be selected, whereby several statistical techniques including MDMC will then be applied to determine forest disturbance thresholds for each watershed individually. The short term objectives (2021-2026) are: (1) to quantitatively determine forest disturbance thresholds on annual mean flows; (2) to determine forest disturbance thresholds high and low flows; and (3) to above results from all 50 watersheds to assess whether climate and watershed property are also controls on these thresholds. My long-term objectives are to assess ecological thresholds or tipping points and resilience in a broader context considering more ecological processes, and to expand spatial scopes to examine forest disturbance thresholds at larger spatial scales. The BC interior is an ideal region for this proposed study because there are numerous gauged watersheds where long-term historic data on hydrology, climate and forest disturbance are available. The proposed research will provide important and timely information for BC to manage forest disturbance to protect aquatic functions. It will allow development of forest disturbance thresholds for effectively managing cumulative hydrological risks. Finally, this project will train 2 HQPs and 5 undergraduate students.