2000-2020年湟水流域植被NDVI变化及其驱动力分析

探究湟水流域植被NDVI时空变化及其驱动因素将有利于地区生态环境的恢复和区域可持续发展。基于多源遥感数据和社会经济数据,利用趋势分析法和皮尔逊相关分析法探究2000—2020年流域植被NDVI时空变化特征,并借助地理探测器分析自然和人为驱动因素对流域内植被空间分异及变化的影响力。结果表明:(1)2000—2020年流域植被NDVI值整体呈现上升趋势,平均增速为0.003 8/a,其中湟水沿岸及下游部分上升趋势最为明显,同时新兴城镇与"引大济湟"工程区存在明显的下降趋势。(2)整个流域内,气温和高程是影响植被NDVI空间分异的主要因素;高程、土壤和植被类型是影响植被NDVI空间变化的主要因素。(3)各驱动因素间的交互作用解释力均高于单因素,呈现出非线性增强与双因子增强的情况,气温与地貌交互作用解释力最高,达到71.6%,对植被NDVI空间分异的解释力最强。(4)流域植被NDVI空间分异及变化受自然因素与人为因素的共同影响,且自然因素的影响起主导作用。随着人们环境保护意识显著提升与地区生态工程逐步落实,流域植被覆盖情况正在转好。

Vegetation NDVI Change and Driving Force Analysis in Huangshui Watershed from 2000 to 2020

Exploring the spatial and temporal changes of vegetation NDVI in Huangshui watershed and its driving factors will be beneficial to regional ecological environment restoration and regional sustainable development. Based on multi-source remote sensing data and socio-economic data, using the trend analysis method and Pearson correlation analysis method to explore the spatial and temporal changes characteristics of vegetation NDVI in Huangshui watershed from 2000 to 2020, and with the help of geographic detector to analyze the influence of natural and anthropogenic driving factors on the spatial variation of vegetation in the basin. The results showed that: (1) From 2000 to 2020, vegetation NDVI value of the watershed presented an overall upward trend, with an average growth rate of 0.003 8/a, among which Huangshui coastal and downstream parts of the most obvious rising trend, while there was an obvious downward trend in new towns and the "water diversion tunnel from Datong river into Huangshui river" project area. (2) In the whole watershed, temperature and elevation were the main factors affecting the spatial variation of vegetation NDVI; elevation, soil and vegetation type were the main factors affecting the spatial changes of vegetation NDVI. (3) The explanatory power of the interaction between the driving factors were higher than that of the single factor, showing a non-linear and two-factor enhancement, temperature and landscape interaction had the highest explanatory power, reaching 71.6%, and explanatory power of the spatial variation of vegetation NDVI was the strongest. (4) The spatial variation and change of vegetation NDVI in the watershed were influenced by both natural and human factors, and the natural factors played a leading role. With the significant improvement of people''s awareness of environmental protection and the gradual implementation of regional ecological projects, the vegetation cover of the watershed is turning better.