| 基于SHAP算法的黄土高原生态分区生态系统水分利用效率的时空格局与驱动机制 |
| 摘要点击 278 全文点击 9 投稿时间：2025-07-23 修订日期：2025-10-31 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 黄土高原 生态分区 生态系统水分利用效率（WUE） 时空格局 驱动机制 |
| 英文关键词 Loess Plateau ecological regionalization water use efficiency（WUE） of ecosystem spatio-temporal pattern driving mechanism |
| DOI 10.13227/j.hjkx.202507295 |
|
| 中文摘要 |
| 生态系统水分利用效率（WUE）是表征陆地生态系统碳水耦合关系的关键指标. 基于多源数据，采用Sen-MK趋势分析、Hurst指数和SHAP可解释机器学习方法，揭示了2000~2023年黄土高原及其6个生态分区（高塬沟壑区A1、A2副区；丘陵沟壑区B1、B2副区；沙地农灌区C区；土石山及河谷平原区D区）WUE的时空演变与驱动机制. 结果表明：①年际上，黄土高原全区及各分区的WUE均呈增加趋势，增速B区最高（以C计，下同）[0.007 g·（m2·mm·a）-1]，D区和A1副区最低[0.001 g·（m2·mm·a）-1]. 除A和D区外，生物因子与人类活动强度是WUE年际变化的主导驱动因子；气候因子对WUE年际变化的影响存在明显的区域差异，降水（P）在A和D区为负效应，其余分区多为正效应，温度除A1副区外多呈正效应. ②空间上，WUE呈“西北低、东南高”的格局，主要受生物与气候因子的共同驱动. 叶面积指数（LAI）和核归一化植被指数（kNDVI）在A、C和D区影响最为显著，B2副区以日光诱导叶绿素荧光（SIF）和LAI为主导. 阈值分析显示，LAI>1或P<300 mm时抑制WUE，kNDVI为0.15~0.25或海拔>2 000 m时促进WUE. 交互效应表明，kNDVI在0.10~0.30且太阳辐射（SR）<2 900 MJ·m-2时促进WUE，SR>2 900 MJ·m-2且LAI<0.60时抑制WUE. 研究成果可为理解黄土高原碳水循环耦合机制及区域生态恢复策略的优化提供科学依据. |
| 英文摘要 |
| Ecosystem water use efficiency （WUE） is a key indicator for characterizing the carbon-water coupling relationship in terrestrial ecosystems. Based on multi-source data， the Sen-MK trend analysis， Hurst index， and SHAP interpretable machine learning method were employed to reveal the spatiotemporal evolution and driving mechanisms of WUE from 2000 to 2023 in the Loess Plateau and its six ecological subregions （High Plateau Gully Region， including A1 and A2； Hilly Gully Region， including B1 and B2； Sandy Farmland Irrigation Region C； Earth-Rock Mountains and Valley Plain Region D）. The results showed that： ① On an interannual scale， the WUE of the entire region and all subregions had been showing an increasing trend. The growth rate was highest in subregion B [0.007 g·（m2·mm·a）-1] （with the unit based on carbon， the same below） and lowest in subregions D and A1 [0.001 g·（m2·mm·a）-1]. Except for in subregions A and D， biological factors and human activity intensity were the dominant driving factors of the interannual variations of WUE. The impact of climatic factors on the interannual variations of WUE exhibited significant regional differences. Precipitation （P） showed a negative effect in subregions A and D， while it mainly exerted a positive effect in other subregions. For temperature， it demonstrated a positive effect in most subregions except in subregion A1. ② Spatially， WUE exhibited a pattern of “low in the northwest and high in the southeast，” primarily driven by the combined effects of biological and climatic factors. Leaf area index （LAI） and kernel normalized difference vegetation index （kNDVI） had the most significant impacts in subregions A， C， and D， while solar-induced chlorophyll fluorescence （SIF） and LAI were dominant in subregion B2. Threshold analysis revealed that WUE was inhibited when LAI > 1 or P < 300 mm and promoted when kNDVI was between 0.15 and 0.25 or elevation > 2 000 m. Interaction effects indicated that WUE was promoted when kNDVI was between 0.10 and 0.30 combined with solar radiation （SR） < 2 900 MJ·m-2 but inhibited when SR > 2 900 MJ·m-2 combined with LAI < 0.60. The research findings provide a scientific basis for understanding the carbon-water cycling coupling mechanism and optimizing regional ecological restoration strategies in the Loess Plateau. |
