School of Forestry and Natural Resources, West Virginia University, 322 Percival Hall, Morgantown, WV 26506, USA.
School of Forestry and Natural Resources, West Virginia University, 322 Percival Hall, Morgantown, WV 26506, USA.
Sci Total Environ. 2019 Dec 1;694:133382. doi: 10.1016/j.scitotenv.2019.07.188. Epub 2019 Aug 2.
Forest headwater catchments are critical sources of water, but climate change and disturbance may threaten their ability to produce reliable and abundant water supplies. Quantifying how climate change and forest disturbances individually and interactively alter streamflow provides important insights into the stability and availability of water derived from headwater catchments that are particularly sensitive to change. We used long-term water balance data, forest inventory measurements, and a multiple-methods approach using Budyko decomposition and paired catchment models to assess how climate change and forest disturbances interact to alter streamflow in five headwater catchments located along a disturbance gradient in the Appalachian Mountains, USA. We found that disturbance was the dominant driver of streamflow changes; disturbed catchments were more sensitive to climate change than the undisturbed catchment; and disturbance was an important factor for a catchment's sensitivity to climate change, principally through changes in species composition and xylem anatomy. Streamflow sensitivity to climate change increased with increasing proportion of diffuse porous species, suggesting that not all disturbances are equal when it comes to streamflow sensitivity to climate change. Climate change effects were masked by disturbance in catchments with high magnitude/low frequency disturbances and amplified in a catchment with low magnitude/high frequency disturbance. Furthermore, critical assumptions of Budyko decomposition were assessed to evaluate the efficacy of applying decomposition to the headwater scale. Our study demonstrates the efficacy and usefulness of applying decomposition to scales potentially useful to resource managers and decision makers. Our study contributes to a more thorough understanding about the impacts of climate change on disturbed headwater catchments that will help managers to better prepare for and adapt to future changes.
森林集水区是重要的水源，但气候变化和干扰可能会威胁到它们提供可靠和充足供水的能力。量化气候变化和森林干扰如何单独和相互作用改变径流量，可以深入了解源自对变化特别敏感的集水区的水资源的稳定性和可用性。我们使用长期水量平衡数据、森林清查测量以及使用 Budyko 分解和成对集水区模型的多种方法，评估了在美国阿巴拉契亚山脉的一个干扰梯度上的五个集水区中，气候变化和森林干扰如何相互作用改变径流量。我们发现，干扰是径流量变化的主要驱动因素；与未受干扰的集水区相比，受干扰的集水区对气候变化更为敏感；干扰是集水区对气候变化敏感性的一个重要因素，主要是通过物种组成和木质部解剖结构的变化。径流量对气候变化的敏感性随扩散多孔物种比例的增加而增加，这表明在考虑径流量对气候变化的敏感性时，并非所有干扰都是相同的。在具有高幅度/低频率干扰的集水区中，气候变化的影响被干扰所掩盖，而在具有低幅度/高频率干扰的集水区中，气候变化的影响被放大。此外，我们评估了 Budyko 分解的关键假设，以评估将分解应用于集水区尺度的效果。我们的研究表明，将分解应用于对资源管理者和决策者可能有用的尺度是有效和有用的。我们的研究有助于更深入地了解气候变化对受干扰的集水区的影响，这将有助于管理者更好地为未来的变化做好准备并适应这些变化。
