Accompanying Data to Hampton, Lin, and Basu (2022) "Forest fire effects on stream water quality at continental scales: a meta-analysis"

Forested watersheds supply over two thirds of the world's drinking water. The last decade has seen an increase in the frequency and intensity of wildfires that is threatening these source watersheds, and necessitating more expensive water treatment to address degrading water quality. Given increasing wildfire frequency in a changing climate, it is important to understand the magnitude of water quality impacts following fire. Here, we conducted a meta-analysis to explore post-fire changes in the concentrations of nitrogen (N) and phosphorus (P) species, dissolved organic carbon, and total suspended sediments in 121 sites around the world. Changes were documented over each study's respective duration, which for 90% of sites was five years or fewer. We find concurrent increases in C, N and P species, highlighting a tight coupling between biogeochemical cycles in post-fire landscapes. We find that fire alters N and P speciation, with median increases of 40%–60% in the proportion of soluble inorganic N and P relative to total N and P. We also found that fire decreases C:N and C:P ratios, with median decreases ranging from 60% to 70%. Finally we observe a 'hockey stick'-like response in changes to the concentration distribution, where increases in the highest concentration ranges are much greater than increases at lower concentrations. Our study documents strong heterogeneity in responses of water quality to wildfire that have been unreported so far in the literature.

森林流域为全球逾三分之二的饮用水提供水源。过去十年间，野火的发生频率与强度均呈上升趋势，正威胁着这些水源流域，同时也迫使人们投入更高成本的水处理工艺以应对水质恶化问题。在气候变化背景下野火愈发频发的当下，明晰火灾后对水质的影响程度至关重要。本研究针对全球121个监测点位开展了荟萃分析，旨在探究火灾后氮（N）、磷（P）形态、溶解性有机碳以及总悬浮沉积物的浓度变化。各研究的监测周期均有记录，其中90%的点位监测时长不超过五年。研究发现碳、氮、磷形态的浓度同步升高，凸显了火灾后景观中生物地球化学循环之间的紧密耦合关系。研究还发现火灾会改变氮磷的形态组成：相较于总氮与总磷，可溶性无机氮、磷的占比中位数提升了40%至60%。此外，火灾会降低碳氮比（C:N）与碳磷比（C:P），其降幅中位数可达60%至70%。最后，研究团队在浓度分布变化中观测到了类似“曲棍球棒”的响应特征：高浓度区间的浓度增幅远高于低浓度区间。本研究揭示了目前文献中尚未被报道的、水质对野火响应的显著异质性。