Identifying the Relationship between Livelihoods and Land Ecosystem Services Using a Coupled Model: A Case Study in the "One River and Two Tributaries" Region of Tibet

In fragile and impoverished areas, identifying the interrelationship between livelihoods and ecosystem services can help protect the ecological environment and improve human well-being. This study selected the "One River and Two Tributaries" region (ORTTR) in Tibet with a fragile, sensitive ecological environment as the study area. With the years 2000, 2005, 2010, 2015, and 2020 as the research time points, a coupled evaluation model of residents' livelihood and land ecosystem services was constructed to study the relationship between the two. Results showed that from 2000 to 2020, the coupling degree and coupling coordination degree between the two continued to increase because of the improvement in residents' livelihood and ecosystem services. The level of coupling coordination gradually changed from a reluctant coordination stage to a moderate coordination stage. The coupling coordination degree showed more revealing results than the coupling degree in time scale. The relative development type between the two was mainly of the type lagging residents' livelihood. By considering the physical geography and socio-economic characteristics and the relative development types, the counties and districts in the ORTTR are divided into ecological conservation areas, ecological restoration areas, and ecological reconstruction areas. The coupled model can evaluate the relationship between livelihoods and ecosystem services from a systematic integration perspective and provide scientific support for the improvement of regional human well-being.