摘要
在全球变化的背景下,刻画植被动态、定量分析气候和人类活动对植被变化的影响对于改善生态系统结构和功能具有重要意义。基于GIMMS-NDVI3g数据、结合土地利用数据和气象数据,采用趋势分析、残差趋势等方法,多尺度、多时段、多类型研究1982-2015年黄河流域植被动态变化,并定量分析气候变化和人类活动对NDVI变化的贡献。结果表明,(1)1982-2015年间,生长季、春季、夏季和秋季NDVI均显著增加;植被明显改善地区主要分布在黄河中下游,而明显退化区域则主要分布在西南部。基于嵌套数据分析发现,随时间序列长度的增加,NDVI增加区域显著扩大。不同土地覆盖类型NDVI的增长速度不同,耕地和林地的增长速度大于其他土地覆盖类型。(2)黄河流域NDVI与气温的相关性更强,植被与温度/降水量相关性随着时段延长而增强。(3)残差趋势法表明,1982-2015年生长季人类活动对黄河流域植被变化的平均贡献率为69%,空间分布上呈现西北部、东部高而西南部、中部低的特征;人类活动贡献率在不同季节存在差异,但均大于气候变化;人类活动对不同季节NDVI变化的贡献率空间分布存在区域差异。黄河流域植被覆盖改善与人类活动息息相关,建议应进一步发挥其在黄河流域西南部地区植被恢复中的作用。
Understand the dynamics of vegetation and their controlling factors related to climate change and human activity is critical to maintain and improve ecosystem structure and function in the context of global change.Here we comprehensively investigated vegetation dynamics and their controls at multiple spatiotemporal scales and across different biomes over the Yellow River Basin(YRB)based on GIMMS-NDVI3g,land use/land cover data and meteorological data from 1982-2015.Trend analysis and residual analysis were used to quantify the contributions of climate change and human activity to NDVI change.Our major findings are summarized below:(1)From 1982 to 2015,averaged NDVI in the growing season,and each subperiod of spring,summer and autumn all increased significantly.The strong greening areas were mainly distributed in the middle and lower reaches of YRB,while the degraded areas were distributed in the southwestern basin.Based on the analysis of nested data,we found that the area of increased NDVI expanded significantly as the length of the time series increased.The increasing rate of NDVI varied among different land cover types,of crop land and forests shower much higher rate than other types.(2)Among the two climate factors,air temperature showed the strongest correlation with NDVI.The relationships between NDVI and climate factors strengthened with time.And(3)our residual analysis showed that human activity contributed the highest to the growing season vegetation change(i.e.,69%of total variations)over the basin during the study period.The contribution exhibited higher in the northwestern and east parts of the basin,but lower in the southwestern and central parts of the basin.Although the contribution of human activity varied among seasons and across regions,they all outperformed the effect of climate change.Overall,our study confirmed the strong positive effect of human activity(mainly related to afforestation and reforestation)on the vegetation improvements in the YRB,an effort that needs to be maintained in the future vegetation restoration over this large basin.
作者
张静
杜加强
盛芝露
张杨成思
吴金华
刘博
ZHANG Jing;DU Jiaqiang;SHENG Zhilu;ZHANG Yangchengsi;WU Jinhua;LIU Bo(State Key Laboratory of Environmental Protection for Regional Eco-Process and Function Assessment/Chinese Research Academy of Environmental Science,Beijing 100012,China;School of Life Science,Lanzhou University,Lanzhou 730000,China)
出处
《生态环境学报》
CSCD
北大核心
2021年第5期929-937,共9页
Ecology and Environmental Sciences
基金
中央级公益性科研院所基本科研业务专项(2019YSKY-026)
国家自然科学基金项目(41001055)。
