Spatial-temporal heterogeneity of ecological quality changes across the Qinghai-Tibet Plateau under the influence of climate factors and human activities

Over the last few decades, the ecological quality of the Qinghai–Tibet Plateau (QTP) has significantly changed due to climate warming, humidification, and increasing human activities. Thus, evaluating this region's ecological quality and dominant factors is crucial for sustainable development. In this study, the changes in the ecological quality on the QTP from 2000 to 2020 were evaluated based on aggregated indices and Sen–MK trend analyses, and the dominant factors affecting the ecological quality of the QTP were quantitatively analyzed using decision tree classification. The results revealed that (1) the ecological quality of the QTP exhibited an overall high trend in the east and a low pattern in the west; (2) the ecological quality of the QTP significantly increased from 2000 to 2020, and human activities were the dominant factors causing this change; and (3) the changes in the ecological quality and dominant factors exhibited obvious spatiotemporal heterogeneity. The area with an improved ecological quality occurred mainly in the northern QTP region. It was governed by human activities and precipitation. In contrast, the area with a deteriorated ecological quality occurred largely in the southern QTP region and was dominated by human activities and temperature. The 2000–2010 period was the most significant period of heterogeneity regarding of ecological quality and its driving factors. (4) The change in the ecological quality was mainly affected by the synergistic relationship between human activities and climate change in this region, which encompassed multiple dominant factors. This study provides important information on the spatiotemporal heterogeneity of ecological quality change and its dominant factors on the QTP and offers systematic guidance for the planning and implementation of ecological protection projects.