浙江省近20年植被变化趋势及驱动因子分析

Trends of Vegetation Change and Driving Factor Analysis in Recent 20 Years over Zhejiang Province

浙江是长江三角洲经济区的重要组成部分,该区域植被变化受到生态气候条件以及人类活动等多种因素的影响。利用多源遥感和地面观测2000—2019年生态植被参量、气象和气候因子以及夜间灯光数据等,分析浙江区域生态植被变化及其驱动关系;利用一元线性回归和Mann-Kendall趋势检验探讨植被变化趋势,采用Pearson相关分析和多元回归方法等研究多元因子贡献率。结果表明,浙江区域近20年增强型植被指数(EVI)呈现显著增长趋势,总增长趋近年均值的7.66%,而总初级生产力(GPP)的增加总量约为多年均值的1.48倍。森林和城市区植被分别呈现显著增长和减少趋势(森林EVI:0.60×10^−3 a^−1。城市EVI:−1.11×10^−3 a^−1)。气温、日照和降水共同影响植被变化特征,其中气温变化是引起区域近20年植被变化趋势的主要气候因子(r=0.54,P<0.01)。夜间灯光变化代表的城市扩张等人为活动是引起城市及周边植被减少的主要原因(r=−0.60±0.13),而远离城市的人类活动对植被生长具有一定的促进作用(r=0.56±0.13)。植被年际变化的多变量贡献分布表明,表征人类活动的夜光数据在全省范围具有重要的影响,而气候因素则会影响局部地区。其中近20年浙江区域气温升高和城市扩张分别对省内植被具有显著的促进和抑制作用。因此,区域气候条件变化以及人类活动是影响浙江省植被生长趋势变化的重要因素。该研究对区域生态文明建设具有重要的参考价值。

The vegetation variation in Zhejiang,the first ecological province in China,which is also an important part of the Yangtze River Delta economic zone,is affected by eco-climatic condition and human activities.In this study,multi-source remote sensing and ground observation of ecological vegetation parameters,meteorological and climatic factors,and night light data from 2000 to 2019 were used to analyze the changes in terrestrial ecological vegetation and its driving relationship.Unitary linear regression and Mann-Kendall trend test were used to explore the vegetation trend variation,and Pearson correlation analysis and multiple regression method were used to study the contribution rate of multiple factors.Aa a result,the enhanced vegetation index(EVI)in Zhejiang Province showed a significant increasing trend in recent 20 years,with the total growth approaching to 7.66%of the annual mean,while the total increase of the gross primary productivity(GPP)was about 1.48 times of the multi-annual mean.Vegetation in the forest and urban area showed significant increasing and decreasing trends(Forest-EVI:0.60×10^−3·a^−1;Urban-EVI:−1.11×10^−3·a^−1).Temperature,sunlight and precipitation affect the characteristics of vegetation variation,and temperature increase was the main climate factor that causes in vegetation increasing trends(r=0.54,P<0.01).Human activities such as urban expansion indicated by night light change were the main cause of vegetation reduction in cities and surrounding areas(r=−0.60±0.13),while that far from cities had a certain promoting effect on vegetation growth(r=0.56±0.13).The distribution of multiple variables’contribution showed that night light data representing human activities had an important influence on the whole province,while climatic factors affected local areas.Regional temperature increase and urban expansion in the past 20 years had significantly promote and inhibit the vegetation growth over Zhejiang Province,respectively.Therefore,regional climate change and human activities are the important factors affecting the trend of vegetation growth in Zhejiang Province,and this research has important reference value for the construction of regional ecological civilization.