黄土高原气候和人类活动对植被NPP变化的影响

Contribution of climatic change and human activities to changes in net primary productivity in the Loess Plateau

本研究基于CASA模型获得黄土高原2000—2018年植被NPP数据集,通过相关性、残差分析等方法,定量分析了气候变化和人类活动对植被NPP变化的影响。结果表明:(1)黄土高原2000—2018年植被NPP呈东南高、西北低分布格局,研究区约86.86%区域植被NPP呈增加趋势,主要为退耕还林还草的核心区;呈下降趋势的面积占13.14%,主要分布在西北部的干旱区。(2)气候变化和人类活动对植被NPP变化的贡献率分别为48.78%和51.22%,在空间上有明显的差异性,人口稀少、发展相对落后地区的植被变化主要受气候变化的影响;人口众多、经济发展较好地区植被变化以人类活动为主。(3)黄土高原作为干旱半干旱区植被对气候变化的响应较为敏感,随着人类活动的日益频繁,气候和人类活动共同作用于黄土高原的植被变化。本研究有助于理解气候变化和人类活动对植被动态变化的影响,并为黄土高原的植被恢复和高质量发展提供科学依据。

In this study,we used the CASA model to produce a net primary productivity(NPP)dataset for the Loess Plateau from 2000 to 2018.Based on correlation and residual analyses,we quantified the relative contribution of climate change and human activities to NPP,with a goal of providing a scientific basis for the formulation of local ecological protection strategies and improving watershed ecological security.The distribution pattern of NPP in the Loess Plateau from 2000 to 2018 was high in the southeast and low in the northwest.The portion of NPP that followed an increasing trend was mainly distributed in the core area of the Grain for Green Program,accounting for 86.86%of the total NPP,whereas the portion of the NPP that followed a decreasing trend was distributed in the northwestern arid zone,accounting for 13.14%of the total NPP.The contribution rates of climate change and human activities to NPP were 48.78%and 51.22%,respectively.Climate change plays an important role in vegetation change in sparsely populated and underdeveloped areas,whereas human activities play an important role in vegetation change in areas with large populations and better economic development.The Loess Plateau,an arid and semi-arid region,has a more sensitive vegetation response to climate change.With the increasing frequency of human activities,climate and human activities jointly determine the vegetation changes.This study contributes to the understanding of the effects of climate change and human activities on the dynamic changes of vegetation.It provides a scientific basis for vegetation restoration and high quality development of the Loess Plateau.