China’s targeted poverty-alleviation policy has eliminated absolute poverty and become the focus of world attention. However, a relative-poverty problem still exists in China, and the large urban–rural income gap is an important issue. Whether the implementation of the targeted poverty-alleviation policy has narrowed the urban–rural income gap, along with its specific effects, requires an accurate analysis, which is particularly critical in order for China to implement a rural-revitalization strategy and further eliminate relative poverty in the future. Given the problems and shortcomings of the existing studies, such as not passing the parallel trend test to overestimate the policy effect, in this study we refer to the previous results, and our analyses divide the 124 counties in Yunnan province into four categories: non-poverty counties and counties with grade-I, grade-II, and grade-III poverty. We selected the panel data of the urban–rural income ratio of each county along with eight influencing factors from 2011 to 2020 for difference-in-difference model (DID) analysis. In this study, we compare the four types of counties level-by-level, and we construct a full-sample spatial DID model. The estimated results, after excluding the impact of COVID-2019, are significant. In addition, we perform robustness and placebo tests and other work on the DID model. All of the results show that the implementation of the targeted poverty-alleviation policy has effectively reduced the urban–rural income ratio in areas experiencing poverty. Finally, we use the intermediary effect analysis method to explore the reasons for the findings: driven by the targeted poverty-alleviation policy, the financial investment in poor areas has substantially increased, further increasing the income level of rural residents in poor areas and thus promoting a notable reduction in the income gap between urban and rural residents in poor areas. We suggest that, although China has achieved comprehensive success in targeted poverty-alleviation, assistance investment still needs to be increased, policies must be adjusted, and income growth must be accelerated to achieve industrial prosperity.

(1) Background: Dianchi Lake is the largest freshwater plateau lake in southwest China. Since the 1970s, with the large-scale lake reclamation and rapid urbanization, the land use/cover of the Dianchi Basin has changed dramatically, directly hindering the sustainable development of the watershed. It is urgent to study the rationality of land use change in order to promote the “win-win” of eco-environment protection and sustainable economic and social development in Dianchi Basin. (2) Methods: The rationality judgment criteria of land use change in Dianchi Basin was constructed from ecological values, land suitability, laws and regulations, and the rationality of land use change in the Dianchi Basin from 1980 to 2020 was evaluated. (3) Results: The rational degree of land use change in the Dianchi Basin was 71.76%, and the level of rationality was low rationality. The rational degree of change in cultivated land, woodland, grassland, water area and construction land was 74.41%, 69.11%, 77.11%, 3.07% and 98.26%, respectively. Among the irrational land changes, 86.59% of the land had changed to construction land. (4) Conclusions: The main problems of irrational land change in the Dianchi Basin are the massive reduction in high-quality cultivated land, the degradation of woodland, and the unordered expansion of construction land. In order to achieve sustainable development, it is important to protect cultivated land, woodland, grassland and lakes.

The basic characteristics of mountain areas are that the innate ecological environment is relatively fragile, the acquired ecological environment is severely damaged and degraded, the whole economy and society are still relatively backward, and the degree of sustainable development is relatively low. At present, it has not been seen that land use sustainability evaluation (LUSE) research lasting for many years based on RS and GIS in mountainous provinces. It is urgent to build a suitable, feasible, operable and applicable LUSE system for mountainous regions so as to provide a basic foundation for strategic planning and management of sustainable land use in mountainous provinces. This study integrated “RS and GIS + multi-phase LUCC + LUSE theory and quantitative practical methods” based on mountain provinces, firmly grasped the basic characteristics of mountain areas—the vulnerability of ecological environment, and conducted the study on mountain LUSE. According to the outcomes of RS of land use in the study area in three phases (2000, 2010 and 2020), a comprehensive indicator system is established from the three dimensions of ecological friendliness of land use (EFLU), the economic viability of land use (EVLU) and social acceptability of land use (SALU). Using the Delphi method to determine weights and combining the AHP method and the comprehensive analysis method, this paper quantitatively measures the overall sustainability of land use (OSLU) of 129 counties in Yunnan province in 2000, 2010 and 2020, revealing the spatio-temporal characteristics of the OSLU of Yunnan province and all counties from 2000 to 2020, and aiming to provide a basic and foundation for strategic planning and management of sustainable land use (SLU) in mountainous provinces. The degree of ecological friendliness (D_EF), degree of economic viability (D_EV), degree of social acceptability (D_SA) and degree of overall sustainability (D_OS) in Yunnan province and all counties have been significantly improved. Accordingly, the OSLU has been improved to a certain extent, with a 0.66% annual growth rate. It indicates that the development and construction from 2000 to 2020 have significantly improved the OSLU. However, regional differences are large. At present, EFLU, EVLU, and SALU in Yunnan province are not high as a whole. The basic situation reflected that there are obvious deficiencies in EFLU, EVLU and SALU in Yunnan province. Land exploitation and use activities have caused certain influences and the destruction of the ecological environment.

The inherent ecological environment of mountainous regions is highly fragile, and the degree of sustainable development is low. There has not yet been a multi-phase ecological vulnerability evaluation (EVE) study based on remote sensing (RS) and GIS for mountainous provinces, for which there is an urgent need to establish a system that is appropriate, practicable and easily operated and applied. In this study, an integrated “RS and GIS + multi-phase land use/cover change (LUCC) + practically quantitative theory and methods of EVE” approach was adopted for analysis based on the interpretation results of five phases of the land use/land cover (LULC) RS images of Yunnan, with 129 counties being considered as the evaluation units. The organic combination of quantitative multi-index comprehensive evaluation (QMCE) and qualitative comprehensive analysis (QCA) methods was adopted to perform quantitative calculations of a system of county-level evaluation indicators which includes “innate” natural ecological vulnerability (INEV), land use ecological vulnerability (LUEV) and land cover ecological vulnerability (LCEV); the degree of ecological vulnerability (DEV) was assessed for the 129 counties within the province during the five study phases (1980, 1990, 2000, 2010 and 2020). The spatiotemporal variation characteristics and laws of DEV from 1980 to 2020 in the whole province and 129 counties were revealed, aiming to provide a basis for meeting the SDGs for mountainous provinces. The results are as follows: (1) Overall, INEV is high because of the high mountains and steep slopes, and the entire province is classified as “highly vulnerable” on average. In terms of counties, more than 79.07% are classified as “moderately vulnerable”, “highly vulnerable” and “very highly vulnerable”. (2) The degree of LUEV and LCEV caused by acquired human socioeconomic activities was higher in 1980. However, after a series of ecological measures in the past 40 years, the values of D_EVLU and D_EVLC in the whole province and counties in 2020 have decreased to different degrees. Accordingly, the degree of overall ecological vulnerability of Yunnan province and counties decreased significantly from 1980 to 2020. The basic law of change is that the number of counties with high DEV decreases significantly, while the number of counties with low DEV increases significantly. (3) The regional difference in the DEV of Yunnan province is large. In general, the degree of ecological vulnerability is lower in the southern, southwestern, western and central areas of Yunnan and higher in the northwest high mountain canyon, northeast mountain areas and east and southeast karst areas. (4) Overall, the DEV in Yunnan province is currently still high. There is an urgent need to enhance the construction of ecological civilization across the whole province and take effective measures to protect the ecological environment according to local conditions, so as to steadily reduce the DEV.