嘉陵江流域植被NPP时空演变及驱动因素探究

Spatiotemporal evolution and driving factors of vegetation NPP in Jialing River Basin

摘要

【目的】植被净初级生产力(NPP)作为陆地生态系统碳循环的重要参与者，探究其时空演变和驱动因素对促进区域生态文明建设具有重要意义。【方法】以嘉陵江流域为研究区域，基于变异系数、Theil-Median趋势法、Mann-Kendall统计检验法、R/S分析法和地理探测器和PLS-SEM模型，分析植被NPP时空演变规律及驱动因素。【结果】NPP时间上呈波动上升趋势，空间上随海拔先增后减；趋势总体稳定，波动“南高北低”,历史极显著增为主，未来分持续增和转减两类。Temp、NDVI、DEM等自然因子主导空间分异，GDP等人为影响显著；交互探测中Temp∩Pre、NDVI∩GDP和Temp∩NDVI解释力最强。PLS-SEM揭示地形通过抑制气候恶化、促进植被生长间接最大促进NPP;气候直接抑制NPP但经植被生长间接正向调节，经人类活动间接抑制；人类活动直接间接均负向。基于未来风险分区，四川盆地应优化植被与城市景观；西北高寒区构建人工-自然协同修复体系；山地丘陵区强化生态红线与廊道；全流域统筹生态补偿与水土保持工程。【结论】嘉陵江流域植被NPP以增加为主，自然因子主导空间分异，Temp∩Pre、NDVI∩GDP和Temp∩NDVI解释力最强。地形通过抑制气候恶化和促进植被生长间接促进NPP,气候直接抑制NPP但通过植被生长间接正向调节，人类活动直接和间接均抑制NPP。未来策略应着重开展分区治理。

Abstract

[Objective] Vegetation net primary productivity(NPP) is a crucial component in the carbon cycle of terrestrial ecosystems. Investigating its spatiotemporal evolution and driving factors is of great significance for promoting regional ecological civilization development. [Methods] Taking the Jialing River Basin as the study area, the spatiotemporal evolution patterns and driving factors of vegetation NPP were analyzed based on the coefficient of variation, Theil-Median trend method, Mann-Kendall statistical test, R/S analysis, geodetector, and PLS-SEM model. [Results] NPP showed a fluctuating upward trend, with spatial variation increasing and then decreasing with elevation. The overall trend remained stable, with fluctuations characterized by “higher in the south and lower in the north”. Historically, extremely significant increases predominated, while future trends were divided into two types: continuous increase and shift to decrease. Spatial differentiation was mainly dominated by natural factors such as temperature(Temp), normalized difference vegetation index(NDVI), and digital elevation model(DEM), while anthropogenic factors such as GDP also had significant effects. In interaction detection, Temp∩Pre, NDVI∩GDP, and Temp∩NDVI demonstrated the strongest explanatory power. PLS-SEM revealed that topography indirectly promoted NPP the most by inhibiting climate deterioration and promoting vegetation growth. Climate directly inhibited NPP but indirectly exerted a positive regulatory effect through vegetation growth, while indirectly inhibiting NPP through human activities. Human activities had negative effects both directly and indirectly. Based on future risk zoning, vegetation and urban landscapes should be optimized in the Sichuan Basin. A synergistic artificial-natural restoration system should be constructed in the northwest alpine area. Ecological redlines and corridors should be strengthened in mountainous and hilly areas. Ecological compensation and soil and water conservation projects should be coordinated across the entire basin. [Conclusion] Vegetation NPP in the Jialing River Basin is mainly increasing, with spatial differentiation dominated by natural factors. Temp∩Pre, NDVI∩GDP, and Temp∩NDVI have the strongest explanatory power. Topography indirectly promotes NPP by inhibiting climate deterioration and promoting vegetation growth. Climate directly inhibits NPP but indirectly regulates it positively through vegetation growth. Human activities inhibit NPP both directly and indirectly. Future strategies should focus on zoned management.

关键词

植被NPP / 时空演变 / 未来趋势 / 地理探测器 / PLS-SEM / 嘉陵江流域 / 影响因素

Key words

vegetation NPP / spatiotemporal evolution / future trends / geodetector / PLS-SEM / Jialing River Basin / influencing factors

基金资助

西华师范大学博士启动项目(21E021)

国家自然科学基金项目(42104089)