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北半球中高纬度陆地生态系统生态脆弱性的时空动态及其气候驱动机制

Spatiotemporal Dynamics and Climatic Drivers of Ecological Vulnerability in Northern Hemisphere Mid- to High-Latitude Terrestrial Ecosystems

  • 摘要: 气候变化正在重塑北半球陆地生态系统格局,中高纬度地区在北极放大效应影响下生态脆弱性问题尤为突出。然而,不同生态系统类型在时空尺度上的生态脆弱性演变特征及其主导气候驱动机制仍缺乏系统量化。基于2001~2023年生长季的MODIS NDVI、CRU及ERA5-Land气候再分析数据,构建“敏感性—适应性”综合评估框架,系统评估了北纬30°以北森林、其他木本植被和草地三类生态系统的生态脆弱性时空动态,并利用结构方程模型揭示了其关键气候驱动机制。结果表明:(1)生态脆弱性空间分异明显,高值区(EV > 0.30)集中于高纬度冻土区,低值区(EV < 0.30)主要分布于温带湿润地区;(2)2013~2023年相较于2001~2012年总体生态系统脆弱性下降,其中森林改善最显著且稳定性最高,而草地生态系统脆弱性最高且改善有限;(3)适度升高的气温是抑制生态脆弱性的主导因子,其效应在高纬度最强;地表太阳辐射增加会显著加剧中纬度生态系统的脆弱性;降水增加在中纬度地区抑制了森林脆弱性,却加剧了草地的脆弱性。本研究揭示了不同生态系统对气候变化响应的差异性及内在驱动机制,强调了制定差异化生态管理策略的必要性,为应对未来气候风险提供科学依据。

     

    Abstract: Climate change is reshaping the terrestrial ecosystem patterns of the Northern Hemisphere, with ecological vulnerability being particularly pronounced in middle and high latitudes under the influence of Arctic amplification. However, a systematic quantification of the spatiotemporal evolution of ecological vulnerability across different ecosystem types and their dominant climate driving mechanisms remains lacking. Based on MODIS NDVI, CRU, and ERA5-Land climate reanalysis data from the 2001~2023 growing seasons, this study constructed an integrated sensitivity-adaptive capacity assessment framework to systematically evaluate the spatiotemporal dynamics of ecological vulnerability for three ecosystems north of 30°N: forest, other woody vegetation, and grassland. Structural equation modeling was used to identify the key climate driving mechanisms. The results indicate that: (1) Ecological vulnerability showed distinct spatial heterogeneity, with high-value areas (EV > 0.30) concentrated in high-latitude permafrost degradation zones and low-value areas (EV < 0.30) mainly distributed in temperate humid regions; (2) Temporally, the overall ecosystem vulnerability decreased during 2013~2023 compared to 2001~2012, with forests showing the most significant improvement and the highest stability, while grassland ecosystems exhibited the highest vulnerability with limited improvement; (3) The climate driving mechanisms differed significantly among ecosystems: air temperature was the dominant factor suppressing ecological vulnerability, with its effect strongest at high latitudes; increased surface solar radiation significantly exacerbated vulnerability in mid-latitude ecosystems; increased precipitation suppressed forest vulnerability but exacerbated grassland vulnerability in mid-latitude regions. This study reveals the differential responses of various ecosystems to climate change and their underlying driving mechanisms, emphasizing the necessity for differentiated ecological management strategies and providing a scientific basis for addressing future climate risks.

     

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