Eco-environmental variability was the basis of ethnic diversity with a persistent influence on the regional development. The unique geographic conditions and multi-ethnic characteristics in southwest China were valuable for exploring sustainable development of ethnic regions. In this study, the regional features of distribution areas of ethnic groups in southwest China were analysed, and it was found that average altitude, slope, water coverage and water form ratio of each ethnic group differed apparently. Additionally, regional features of southern minorities were relatively stable, while those of northern minorities changed evidently from 1990 to 2010. Furthermore, taking the spatial coordinates and regional features as parameters, fifty-eight ethnic groups were clustered into six categories via spatial cluster analysis. Moreover, based on the county-level population data, the ethnic similarities in southwest China were identified by correlation analysis, and the results were in accordance with those of spatial cluster analysis but more detailed. In addition, the eco-environmental adaptability of various ethnic groups was discussed in terms of living and production as well as regional sustainable development. This research was of referential meaning for population settlement, natural resources utilization and biodiversity conservation in multi-ethnic regions.

Developing modern circular agriculture is one of the important ways to promote agricultural sustainable development, facilitating the achievement of the Sustainable Development Goals adopted by the United Nations. However, when agricultural production operators constructed particular systems, they often lacked accurate data support and parameter matching. Consequently, problems such as unknown input and output, low circulation efficiency, and lack of comprehensive evaluation occurred, increasing challenges for efficient circulation of the systems. Therefore, based on sufficient data collection and field investigation, this research integrated emergy analysis and life cycle assessment to conduct sustainability evaluation on the modern Straw–Sheep–Cropland agro-pastoral circular system. Then the system was optimized by means of coupling parameter adjustment and key technology regulation. The results showed that the whole system required lower total emergy input after optimization. And the total weighted value of potential environmental impacts of the optimized system was 47.12% of that of the original system. Meanwhile, annual environmental service emergy in air, water, and soil was reduced significantly compared with the original one. In general, the optimized system had good performance in reduction, reuse, and controllability, so its sustainability was also high. This research formed a systematic method suitable for evaluating and optimizing the modern agro-pastoral circular system, which provided accurate guidance for the scientific construction and sustainable development of circular agriculture systems.