Climate Change and Human Activities Contribute to the Enhancement Recovery of Grassland Productivity in Xinjiang

Grasslands, as a vital component of arid and semi-arid terrestrial ecosystems, play a pivotal role in carbon cycling and ecosystem functioning. Climate change and human activities significantly affected grassland productivity. Understanding the main driving factors and their contribution rates is of great significance for the protection and sustainable development of grasslands. However, we still lack a comprehensive understanding of the changes in grassland productivity and their driving factors in Xinjiang. This study investigated the spatiotemporal characteristics and underlying driving factors of grassland actual net primary productivity (AcNPP) in Xinjiang from 2000 to 2022, utilising the Carnegie-Ames-Stanford Approach and geospatial detectors. Employing the nonlinear Random Forest technique, we assessed the dual impacts of climate change and human activities on grassland productivity. Our findings revealed that grassland productivity in Xinjiang exhibited fluctuating growth during this period, with an average annual AcNPP growth rate of 0.33 g C m-2 year-1. Comprehensive evaluation revealed that soil type, precipitation, and soil moisture content were the key determinants of the spatial distribution of AcNPP, with higher values in mountainous regions and lower in basins. The study further revealed that climate change, human activities, and their combined effects contributed to the recovery of 60.97% of grasslands in Xinjiang. However, human activities were the primary drivers of grassland degradation, with a contribution rate reaching 67.71%. Further analysis indicated that water conditions, particularly precipitation and soil moisture content, were the main forces driving grassland changes in Xinjiang. Although grazing management strategies, such as rotational stocking and deferred stocking, facilitated grassland recovery in 36.71% of areas impacted by human activities, grazing remains a significant anthropogenic factor contributing to grassland degradation. These findings provide valuable scientific insights for the effective management and conservation of Xinjiang's grassland ecosystems.