Assessment of the Effect of Climate Change and Human Activities on Vegetation Dynamics and its Vulnerability

Abstract

Abstract It is necessary to evaluate the impacts of climate change and human activities on vegetation dynamics. The purpose of this study is to assess the linkage of vegetation cover and climate change and distinguish the contribution of climate change and human activities on vegetation and its vulnerability in Namak Lake basin, Iran. For this purpose, changes in the Enhanced Vegetation Index (EVI) in association with Standardized Precipitation Evapotranspiration Index (SPEI) during 2000–2019 were analyzed. Then, the roles of climate change and human activities on vegetation vulnerability were assessed in various Land Use Land Cover (LULC) classes using the residual analysis and Probability of Vegetation Vulnerability Index (PVVI). The results indicated that vegetation cover was mainly dependent on short-term climatic changes and their correlation decreased with increasing time scale of SPEI. It reflected that short-term water availability was vital for vegetation growth. Also, the sparse vegetation cover was mainly more vulnerable to climate change. Residual analysis showed that the vegetation dynamics was intensively attributed to the climate change, so that climate change affected vegetation cover in 78.96% of the basin, while 15.58% was affected by human activities and 5.46% was affected by both factors. The value of PVVI in the regions affected by climatic change was the highest (55.99), in the regions affected by human activities it was lower (50.40), and in the regions affected by both factors was between the other two numbers (50.93). The results can provide useful recommendations for designing the restoration plans in arid and semi-arid areas.