定量评估气候变化与人类活动对西北地区草地变化的相对作用  

Quantitative Assessment on the Relative Effects of Climate Variation and Human Activities on Grassland Dynamics in Northwest China

作　　者：同琳静 刘洋洋 章钊颖 李晓宇 王倩[1] 李建龙[1] TONG Linjing;LIU Yangyang;ZHANG Zhaoying;Li Xiaoyu;WANG Qian;Li Jianlong(Department of Ecology,School of Life Science,Nanjing University,Nanjing 210093,China;International Institute for Earth System Sciences,Nanjing University,Nanjing 210046,China)

机构地区：[1]南京大学生命科学学院生态学系,南京210093 [2]南京大学国际地球系统科学研究所,南京210046

出　　处：《水土保持研究》2020年第6期202-210,共9页Research of Soil and Water Conservation

基　　金：国家重点研发计划项目(2018YFD0800201);国家重点基础研究发展计划(973计划)(2010CB950702);国际APN全球变化项目(ARCP2015-03CMY-Li)。

摘　　要：为了定量区分气候和人为因素在草地动态过程中的相对贡献,基于遥感数据和人为因素数据,结合CASA模型和Thornthwaite Memorial模型,定量评估了气候变化和人类活动对西北地区草地净初级生产力(NPP)的影响,结果表明:(1)2000—2015年,西北地区83.2%的草地呈现恢复状态,而仅有16.8%的草地呈现退化趋势。NPP的增加量为18645.56 Tg C,NPP损失量为428.16 Tg C。(2)人类活动是草地恢复的主要成因,其主导恢复的草地面积和NPP总量分别为1.11×106 km 2和10478.4 Tg C。而草地退化主要由气候变化引起,气候变化主导的草地退化面积占草地总面积的9.97%,造成的NPP损失量341.76 Tg C。(3)西北地区草地恢复主要归因于草地保护政策实施,而干旱的缓解是草地呈现恢复的主要气候原因。草地退化主要由区域水热状况不均衡和不合理人类活动(人口增加、过度放牧和草地开垦等)造成。In order to quantitatively distinguish the relative contributions of climate and human factors in the process of grassland dynamics,based on the remote sensing data and human factor data,combination of CASA model and Thornthwaite memorial model,the relative contributions of climate variation and human activities to grassland primary net productivity(NPP)in northwest China were quantitatively assessed.The results showed that:(1)83.20%of total grassland area exhibited restoration during 2000—2015,while only 16.8%underwent degradation;the increment of total NPP was 18645.56 Tg C,and the loss of total NPP was 428.16 Tg C;(2)human activities were the main reason for grassland restoration;the human-induced restoration areas and NPP loss were 1.11×106 km 2 and 10478.4 Tg C,respectively;grassland degradation was mainly caused by climate variation;the climate-induced grassland degradation area accounted for 9.97%of the total grassland area,resulting in loss of 341.76 Tg C of NPP;(3)further analysis demonstrated that the restoration in northwest China mainly attributed to the implementation of the grassland protection policies,while the mitigation of drought was main climatic factor for grassland restoration.Unbalance of local hydrothermal condition(climatic factor)and irrational human activities(population increase,overgrazing and grassland reclamation)were the reasons for grassland degradation.

关 键 词：净初级生产力 草地 气候变化 人类活动 西北地区 

分 类 号：Q948[生物学—植物学] P467[天文地球—大气科学及气象学]