Spatiotemporal variation of enhanced vegetation index in the Amazon Basin and its response to climate change

The Amazon Basin plays an important global ecological role. Understanding the temporal and spatial changes of vegetation in the Amazon Basin and the response of vegetation to climatic factors is essential for global climate change adaptation. However, the respective contributions of precipitation and temperature variability to vegetation dynamics in the Amazon Basin remains unclear. In this study, we investigated the annual variation of the enhanced vegetation index (EVI) and the relationship between EVI and hydrothermal conditions in the Amazon Basin from 2000 to 2019. The results indicate that EVI and precipitation have slightly increased in the Amazon Basin over the past 20 years, whereas temperature has significantly increased. Spatially, the EVI shows an increasing trend in most areas and a decreasing trend in some local areas. The spatial heterogeneity of precipitation is apparent, which is higher in the south and lower in the north. Across the basin, both precipitation and temperature have significant positive effects on the EVI. Seasonally, the positive impact of climatic factors on vegetation growth in the dry season was greater than that in the wet season. Furthermore, the results show that vegetation dynamics are impacted more by precipitation than temperature in regions that receive less than 2000 mm/yr of precipitation, while temperature is the dominant factor where the annual precipitation is over 2000 mm/yr. The research results provide scientific evidence of the effect of climate change on vegetation dynamics and can support local government policy making for the protection of vegetation in the Amazon Basin.