基于情景分析的九寨沟世界自然遗产地生态系统服务时空变化

Spatiotemporal changes in ecosystem services in the Jiuzhaigou World Heritage Site based on scenario analysis

为明确九寨沟世界自然遗产地在土地利用变化与气候变化下的生态系统服务变化过程,针对植被净初级生产力(NPP)、水源涵养、土壤保持3种区域最主要的生态系统服务功能进行时空动态评估,并基于情景构建开展研究.结果表明:(1)3种生态系统服务供给量在1990-2015年间呈现下降趋势,其中NPP降幅最大,由1990年的13.774×10^5 t下降至2015年的10.834×10^5 t,降幅为21.34%.(2)3类情景下,生态系统服务供给量及空间分布均存在较大差异.在生态系统服务供给总量上整体呈现土地利用变化情景(情景2)>真实变化情景(情景1)>气候变化情景(情景3)的变化趋势,在情景2下,NPP增长0.29×10^3 t,水源涵养、土壤保持分别减少0.008×10^8 m^3、0.002×10^6 t,变化幅度均小于情景1、情景3.不同情景的比较结果表明仅由土地利用变化导致的九寨沟生态系统服务供给总量变化较其他两类情景更小,且其供给总量也最大;同时,暖干化的气候变化趋势对九寨沟生态系统服务的供给产生了显著的负面效应,也在一定程度上影响了生态系统服务变化的空间格局,尤其是对水源涵养功能的影响较为显著.

This study aimed to clarify the spatiotemporal dynamics of ecosystem services in the Jiuzhaigou World Natural Heritage site and,thus,to reveal the changing process of ecosystem services driven by land use change and climate change.Based on the evaluation of the three main ecosystem services,net primary productivity(NPP),water conservation,and soil conservation,this study constructed three types of change scenarios to reveal the progress of ecosystem services in the Jiuzhaigou World Natural Heritage site.The results showed that:(1)The supply of three ecosystem services showed a downward trend from 1990 to 2015,in which NPP decreased the most,from 13.774×10^5 t in 1990 to 10.834×10^5 t in 2015,with a decrease rate of 21.34%.(2)There were significant differences in the total supply and composition structure of the three scenarios.Among them,the overall trend was scenario 2(land use change)>scenario 1(real change)>scenario 3(climate change)with respect to the level of service supply.Under scenario 2,NPP increased by 0.29×10^3 t,the supply of water conservation and soil conservation decreased by 0.008×10^8 m^3 and 0.002×10^6 t,respectively,and the change range was smaller than that in scenarios 1 and 3.Through a comparison of different scenarios,this study showed that the change in the total supply of ecosystem services caused by scenario 2 was smaller than that of the other two scenarios.At the same time,the climate change trend of warming and drying had a significant negative effect on the supply of ecosystem services in Jiuzhaigou,and also affected the spatial pattern of ecosystem services,especially the water conservation function.