Soil erosion can potentially threaten different resources inside and outside of burned areas, and the risk of water becoming contaminated with sediment may be particularly severe. Various postfire actions, such as applying straw mulch, have been carried out in northwestern Spain in recent years with the aim of mitigating the risk of soil erosion. Nonetheless, because of the short interval between summer wildfire and autumn rains, careful selection and prioritization of the areas to be treated is crucial. Changes in hydrological connectivity could be measured and used as a criterion for selecting such areas. However, studies addressing changes in hydrological connectivity as a consequence of forest fires are scarce. In the present study, we assessed the effects of fire and postfire helimulching on the hydrological connectivity and sediment loads in a forest catchment burned by a wildfire in August 2016. Sediment yields were recorded in 20 plots (180 m²). Hydrological connectivity was computed with a version of the Borselli index and two alternative weighting factors: the C factor from the Revised Universal Soil Loss Equation and a factor based on field surveys of soil burn severity. The effect of mulching was also considered. The results indicate that the version of the Borselli index based on field measurements of soil burn severity best reflects the susceptibility to postfire sediment delivery. Moreover, this method was also suitable for evaluating the effect of mulching on soil erosion. The study findings may help forest managers to plan postfire actions.

中文翻译：

---

探索水文连通性和土壤燃烧程度对野火和覆盖后沉积物产量的影响

水土流失可能会威胁到烧毁地区内外的各种资源，并且水被沉积物污染的风险可能特别严重。近年来，在西班牙西北部已采取了各种后火行动，例如使用秸秆覆盖物，目的是减轻水土流失的风险。但是，由于夏季野火与秋季降雨之间的时间间隔很短，因此精心选择要处理的区域并确定其优先级至关重要。可以测量水文连通性的变化，并将其用作选择此类区域的标准。但是，针对因森林大火而引起的水文连通性变化的研究很少。在目前的研究中，²）。使用Borselli指数的版本和两个替代加权因子计算水文连通性：修订后的通用土壤流失方程式中的C因子和基于土壤烧伤严重性的现场调查得出的因子。还考虑了覆盖的效果。结果表明，基于土壤烧伤严重程度的野外测量的Borselli指数版本最能反映出火灾后泥沙输送的敏感性。而且，该方法也适用于评价地膜覆盖对土壤侵蚀的影响。该研究结果可能有助于森林管理者计划火灾后的行动。