滇中城市群植被生产力演变轨迹及其影响因素

Evolutionary Trajectories of Vegetation Productivity and Their Driving Factors in the Central Yunnan Urban Agglomeration

  • 摘要: 滇中城市群作为西部大开发的重点区域、生态文明建设的先行示范标杆, 开展其植被生态系统生产力的演变轨迹研究, 对改善区域生态环境质量与特色风貌、构建高原宜居型城市群具有重要的理论与实践意义。基于MOD13A3 Ⅵ版归一化差异植被指数(NDVI)数据, 通过多模型轨迹诊断法和空间随机森林等方法, 分析了2000-2022年滇中城市群植被生态系统生产力演变轨迹及其自然社会影响因素。结果表明: (1)2000-2022年, 滇中城市群植被生态系统生产力演变呈正向、负向及无明显趋势轨迹数占比分别为71.55%、6.67%和21.78%;其中正向轨迹以线性演变类型为主导, 负向轨迹则以突变演变类型占比最高。研究区植被生态系统生产力演变轨迹整体呈正向上升趋势, 大面积区域植被生产力实现持续稳定提升, 部分区域则保持相对稳定状态, 且全域范围内植被生产力的正负突变现象均较为频繁。(2)植被生产力正向演变轨迹主要分布于研究区北部及西南部区域, 负向演变轨迹则集中在中东部与中南部区域。在1 000~3 000 m海拔范围内, 较低海拔区域负向轨迹数占比较大, 而较高海拔区域正向轨迹数占比较大。(3)人类活动对滇中城市群植被生产力的影响程度显著高于自然因素, 其中人类活动因子中以夜间灯光、人口密度的影响最为突出, 自然因子则以年平均气温、潜在蒸散发及土壤全氮含量的作用更为显著; 林地、耕地、草地向建设用地的转化, 易催生大量植被生产力负突变轨迹; 年平均气温、降雨量和潜在蒸散发3者交互影响植被生产力。本研究结果可为滇中城市群的城市规划编制、生态修复实践及生态环保工程实施提供科学参考与决策支撑。

     

    Abstract: As a key region in China's Western Development Strategy and a leading exemplar of ecological civilization construction, the Central Yunnan Urban Agglomeration (CYUA) is pivotal for regional sustainable development. Investigating the evolutionary trajectories of vegetation ecosystem productivity in CYUA is essential for improving regional ecological quality and landscape character, as well as supporting the development of a livable plateau urban agglomeration. Based on MOD13A3 Version VI normalized difference vegetation index (NDVI) data, this study analyzed the spatiotemporal evolution of vegetation ecosystem productivity trajectories and their natural and socio-economic drivers in CYUA from 2000 to 2022 using a multi-model trajectory diagnosis framework and a spatial random forest model. The results indicate that: (1) During 2000-2022, vegetation ecosystem productivity trajectories in CYUA comprised 71.55% positive, 6.67% negative, and 21.78% non-significant trends. Linear trajectories dominated positive trends, whereas negative trajectories were most frequently characterized by abrupt declines. Overall, vegetation productivity exhibited an upward tendency, with large areas showing sustained and stable improvement, while abrupt shifts between positive and negative occurred frequently across the region. (2) Positive trajectories were mainly distributed in the northern and southwestern regions, whereas negative trajectories clustered in east-central and south-central areas. At elevations of 1 000-3 000 m, negative trajectories predominated at lower elevations, while the proportion of positive trajectories increased with elevation. (3) Human activities exerted stronger impacts than natural factors on vegetation productivity. Nighttime light intensity and population density were key anthropogenic drivers, whereas mean annual temperature, potential evapotranspiration, and total soil nitrogen were the dominant natural drivers. Land-use conversions from forestland, cropland, and grassland to construction land tended to induce significant negative abrupt shifts in vegetation productivity. Interactive effects among temperature, precipitation, and potential evapotranspiration critically shaped productivity patterns. These findings provide a scientific basis and decision support for urban planning, ecological restoration, and environmental protection engineering in CYUA.

     

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