2000—2020年广西植被生态质量变化及驱动力分析

Analysis of vegetation ecological quality change and its driving forces in Guangxi from 2000 to 2020

关键词:  植被生态质量, 时空演变, 驱动力, 遥感, 广西

Key words:  vegetation ecological quality, temporal and spatial evolution, driving force, remote sensing, Guangxi

摘要:

为掌握广西植被生态质量的时空变化特征及其驱动机制,该文以植被生态质量指数(ecological quality index,EQI)为评价指标,基于气象、地形、土壤和遥感等多源数据,利用线性趋势分析、相关性分析、地理探测器等方法,分析了2000—2020年广西植被生态质量的时空变化特征及其驱动力。结果表明:(1)2000年以来广西植被生态质量指数呈显著增加趋势,区域植被生态明显改善。植被生态质量发展经历了缓慢增长、迅速增长、显著提升等演变阶段。在空间上,广西植被生态质量指数呈现四周高,中间低的特征,高值区逐渐由东部向西部和北部扩展。(2)广西植被生态质量时空演变影响因素差异显著。随海拔高度上升植被生态质量总体变化呈“增加—下降—稳定—上下波动”的趋势。壤土的植被生态质量高,砂土的植被生态质量低。森林和灌草的生态质量较高,农田植被的生态质量较低。植被生态质量与气候驱动因素呈显著正相关关系,受气温和降水共同影响,其中以气温为主要驱动(T)的区域面积最广,降水为主要驱动(P)的区域面积次之,气温降水强驱动([T+P]⁺)和弱驱动([T+P]^-)的区域面积较小。(3)广西植被生态质量变化驱动力受地形、土壤、植被、气候、自然灾害和人类活动的共同影响。自然影响因子解释力排序为植被>地形>土壤>气候,其中植被净初级生产力和植被覆盖度是影响植被生态质量时空分异的最主要因素。自然因子对广西植被生态质量变化的影响存在交互作用,均呈非线性增强及双因子增强关系,其中地形与植被、土壤与植被、气候与植被因子交互作用最明显。自然灾害和人类活动加剧了植被生态质量变化的影响,其中干旱和低温冷害等气象灾害抑制了植被生态质量的改善,而林业生态工程等人为活动促进了植被生态质量的提升。该研究结果为合理制定广西植被生态保护与修复措施提供了科学理论依据和技术支撑。

Abstract:

In order to grasp the spatiotemporal variation characteristics and driving mechanism of vegetation ecological quality in Guangxi, based on multi-source data such as meteorology, terrain, soil and remote sensing, and using the ecological quality index(EQI)as an evaluation indicator, linear trend analysis, correlation analysis and geographical detector method were used to analyze the spatiotemporal variation and driving mechanisms from 2000 to 2020. The results were as follows:(1)Since 2000, the vegetation EQI of Guangxi had significantly increased, and the regional vegetation ecology had improved significantly. The development of vegetation ecological quality had experienced stages of slow growth, rapid growth and significant improvement. In terms of space, the vegetation EQI in Guangxi showed a characteristic of high in four directions and low in the middle, with the high-value areas gradually expanding from the east to the west and north.(2)The influencing factors of spatiotemporal evolution of vegetation ecological quality in Guangxi were significantly different. The overall change of vegetation ecological quality at different altitudes showed a trend of ‘increase-decrease-stability-fluctuation'. The vegetation ecological quality in different soil types was high in loam soil and low in sandy soil. The ecological quality of forest and shrub-grass was high, and the ecological quality of farmland vegetation was low. There was a significant positive correlation between vegetation ecological quality and climate driving factors, which was affected by both temperature and precipitation. The area mainly driven by temperature(T)was the widest, followed by the area mainly driven by precipitation(P). The areas driven strongly([T+P]⁺)and weakly([T+P]^-)by temperature and precipitation were smaller.(3)The driving force of changes in vegetation ecological quality change of Guangxi was affected by terrain, soil, vegetation, climate, natural disasters and human activities. The order of explanatory power of natural influencing factors was vegetation > terrain > soil > climate, in which the vegetation net primary productivity and vegetation coverage were the most important factors affecting the spatiotemporal variation of vegetation ecological quality. The effects of natural factors on vegetation ecological quality in Guangxi was interactive, showing a nonlinear enhancement and two-factor enhancement relationship, and the interaction between terrain and vegetation, soil and vegetation, and climate and vegetation were the most obvious. Natural disasters and human activities aggravated the impact of vegetation ecological quality change. Among them, meteorological disasters such as drought and low temperature damage inhibited the improvement of vegetation ecological quality, while human activities such as forestry ecological engineering promoted the improvement of vegetation ecological quality. The research results provide a scientific theoretical reference and technical support for making reasonable measures of vegetation ecological protection and restoration in Guangxi.