甘肃祁连山国家级自然保护区水源涵养量的时空变化

基于水量平衡及水源涵养深度计算方法，研究了2000 ? 2018年甘肃祁连山国家级自然保护区水源涵养深度的时空变化及其驱动力。结果表明，多年平均水源涵养深度为34.23 mm，水源涵养总量为8.56 × 108 m3·a?1。林地、草地和湿地的水源涵养深度显著高于耕地和未利用地(P < 0.05)。多年平均水源涵养深度的空间分布表现为中东部高而西北部低，水源涵养深度越高其年际变幅越大。研究时段内水源涵养深度总体呈不显著变化，显著增加区主要集中在中高海拔区，显著减少区主要分布在低海拔区(P < 0.05)。水源涵养深度的时空变化主要受降水量和土地覆盖类型的影响，其次是叶面积指数和温度。水源涵养深度与降水量显著正相关(P < 0.05)，与叶面积指数和气温负相关。建议将保护区中东部设为水源涵养保护优先区，强化对林地、草地和湿地的保护。在气候暖湿化背景下，未来保护区水源涵养深度将保持稳定态势。

Spatiotemporal variability in the water conservation amount in Gansu Qilian Mountain National Nature Reserve

Based on calculations of water balance and water conservation depth, this study analyzed the spatiotemporal variation of water conservation depth and its main driving forces in Gansu Qilian Mountain National Nature Reserve during 2000 ? 2018. The results showed that the annual average water conservation depth was 34.23 mm, with the total water conservation amount reaching 8.56 × 108 m3·a?1. The water conservation depth of woodlands, grasslands, and wetlands was significantly higher than that of cultivated and unused land (P < 0.05). The water conservation depth was higher in the middle and eastern parts but lower in the northwestern part. Areas with higher values of water conservation depth showed greater inter-annual variability. The overall trend in water conservation depth was not significant for the entire study period. Areas with significant increases in water conservation depth grouped at middle-high altitudes, whereas areas with significant decreases in water conservation depth were distributed mainly at low altitudes (P < 0.05). The spatiotemporal variation of water conservation depth was driven by changes in precipitation and land cover types, followed by leaf area index and temperature. A significant positive correlation between water conservation depth and precipitation was observed (P < 0.05), together with a negative correlation of water conservation depth with leaf area index and temperature. The middle and eastern Gansu Qilian Mountain National Nature Reserve is the priority area for water conservation, and the protection of woodlands, grasslands, and wetlands should be strengthened. Under the background of a warm-humid climate, water conservation depth is projected to remain stable in the future.