Ecological Carrying Capacity and Driving Factors of the Source Region of the Yellow River in China over the Past 30 Years

The source region of the Yellow River (SRYR) serves as a crucial ecological barrier on the Qinghai–Tibet Plateau in China. In recent decades, the ecological condition of the SRYR has deteriorated, resulting in a state of ecological insecurity. This state of affairs endangers the region's living environment, aggravates poverty, and seriously hinders the region's sustainable ecological, social, and economic development. Ecosystems, landscape patterns, ecological carrying capacity (ECC), and drivers interact with each other in the region, shaping the regional ecological pattern's past, present, and future. However, the specific mechanisms underlying these interactions have yet to be elucidated. Based on the land use type data of the SRYR in China for the last 30 years in seven periods (1990, 1995, 2000, 2005, 2010, 2015, and 2020), and combined with the ecological footprint method, we carried out a study of spatial and temporal changes at the county scale and the source region scale, used the landscape pattern index to describe the changes in ECC, and analyzed the main drivers that affect the ECC of the source region. The results indicate the following: (1) Over the past 30 years, the greatest changes in the area have occurred in grasslands and unused lands. Between 2005 and 2010, a significant conversion of unused lands to grasslands occurred in the SRYR, amounting to 7382.33 km2, mainly distributed in Maduo County and Maqin County. (2) The absolute ecological carrying capacity (AECC) of grasslands in the SRYR has shown an upward trend, while that of forests has declined. The ECC of the source region has generally increased, with higher ECC observed in Maqin County, Maduo County, and Xinghai County. (3) The spatial distribution of ECC in the SRYR has shown non-uniform changes, with an increasing trend observed across all county-level areas. The spatial heterogeneity of AECC is high, with minor overall spatial distribution changes. (4) There is a positive correlation between the ECC of the SRYR with SPLIT, PARA_MN, and COHESION (p < 0.05). The impact of landscape pattern indices on ECC ranked as COHESION > PARA_MN > SPLIT. (5) Principal component analysis indicates that the primary driving forces of the SRYR's ECC are social factors, such as urban population (X5) and per capita GDP (X8), with natural factors being less significant than social factors. This research is crucial for maintaining ECC in the SRYR, protecting and restoring the ecological environment, and ensuring the sustainable development of the economy and society.