Revealing the vegetation trend shifts related to meteorological and hydrological factors in central Asian endorheic basins

Abstract

The terrestrial vegetation ecosystems of Central Asia’s endorheic basins are highly vulnerable due to water limitation. Intensifying human activities and climate change have exacerbated water scarcity, posing a growing threat to regional ecological stability. Understanding the mechanisms underlying vegetation responses to meteorological and hydrological factors is crucial for addressing regional climate change. However, these interactions remain insufficiently explored, highlighting a critical gap in current research. Here, we apply a time series breakpoint detection method and structural equation modeling to analyze long-term vegetation trends (1982–2020) and their relationship with meteorological and hydrological factors. We find that 65.2% of vegetation sequences exhibited a high probability of turning points, while 82.9% experienced substantial trend shifts. Additionally, 12.7% of vegetation showed a monotonic greening trend, whereas 4.4% exhibited persistent browning. Notably, natural vegetation was more prone to trend shifts compared to irrigated vegetation. Trend shifts were most pronounced during 2001–2010 accounts for 53.1% of the study area, coinciding with heightened vegetation sensitivity under conditions of excessive water consumption. A subsequent vegetation recovery was observed in 2011–2020 with more than 50% of the vegetation sensitivity index value dropping below 50 or even smaller. Precipitation, temperature, and surface net solar radiation were the primary factors of vegetation trend shifts, fundamentally shaping the relative evolutions in vegetation trend shifts and sensitivity. Despite improvements in water availability, vegetation surrounding the Aral Sea remains highly sensitive, facing an elevated risk of ecological degradation. These findings underscore the urgent need for sustainable, integrated water resource management to safeguard natural vegetation and enhance ecological resilience across central Asia’s endorheic basins.