Context Hydrological connectivity (HC) reflects the flow processes of water and sediment thus affects hydrological services at different scales. Water retaining forest plays an important role in the sustainability of water regulation and provision. Objectives Used the water-holding forest area of the Honghe Hani Rice Terraces World Heritage Site as the study area and, with a modified HC, to calculate and analyze the lateral and longitudinal HC and to identify the conservation priority areas. Methods We modified the popular Borselli’s index of connectivity (IC) into MIC by introducing soil factors with 81 samples, analyzed the HC characteristics by sampling belts, identified the conservation priority area by hotspots analysis at watershed and sub-watershed scales, and verified the MIC with field-measured water level and FIC index. Results The HC value follows a normal distribution with the average value of 8.03. Its lateral characteristics decrease from river valleys to mountain ridges, whereas its longitudinal characteristics decrease from lower to higher rainfall; this result reflects an obvious spatial gradient distribution of water-holding functions along elevation. Hotspot analysis shows that subwatersheds F and G are the conservation priority region for water-holding. The precision of the MIC is better than Borselli’s IC because of the addition of soil factors. Conclusions The MIC is an effective index to reflect the spatial gradient or patchy pattern of hydrological services. Its patterns can be identified by their lateral and longitudinal directions or by the hotspots of spatially clustered yet connected areas of high water-holding capacity.

中文翻译：

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绘制横向和纵向水文连通性图以确定红河哈尼梯田世界遗产地蓄水林的优先保护区域

背景 水文连通性（HC）反映了水和泥沙的流动过程，从而影响不同尺度的水文服务。保水林在水资源调节和供应的可持续性方面发挥着重要作用。目的以红河哈尼梯田世界遗产地保水林区为研究区，采用修正后的HC，计算分析横向和纵向HC，确定优先保护区域。方法通过引入81个样本的土壤因子，将流行的Borselli连通性指数（IC）修改为MIC，通过采样带分析HC特征，通过流域和亚流域尺度的热点分析确定保护优先区域，并验证MIC具有现场测量的水位和 FIC 指数。结果 HC 值服从正态分布，平均值为 8.03。横向特征由河谷向山脊递减，纵向特征由降雨量少向高递减；这一结果反映了沿高程的蓄水功能空间梯度分布明显。热点分析表明，子流域 F 和 G 是蓄水保护优先区域。由于加入了土壤因素，MIC 的精度优于 Borselli 的 IC。结论 MIC是反映水文服务空间梯度或片状格局的有效指标。它的模式可以通过它们的横向和纵向或通过空间聚集但连接的高持水能力区域的热点来识别。