Simple SummaryThe Yunnan snub-nosed monkey is one of the most endangered species on the IUCN Red List. The study of its population changes and its habitat quality and rarity changes over time are important for identifying opportunities for conserving and improving habitat quality while minimizing the adverse impact on ongoing human socio-economic development. Conserving and improving habitat quality is an important part of protecting and improving habitat diversity and biodiversity. Minimizing adverse impact to human development is important for earning energetic buy-in from the local people needed for long-term sustainability of such opportunities. Habitat Quality measures the land cover for an area at a given point in time compared to the preferences of a species or group of species. A high habitat quality indicates a large part of the area has land cover the species prefers, such as Huashan Pine for the Yunnan snub-nosed monkey. Habitat Rarity represents the change in rarity of a land coverage type (such as Huashan Pine) in an area over two points in time. A high habitat rarity indicates the land coverage type significantly decreased between the two points in time. A high Huashan Pine rarity, for example, means a significant decrease in the Yunnan snub-nosed monkey’s most preferred land cover and hence will likely significantly impact the monkey’s survival. Our analysis of the change in habitat quality and habitat rarity over time indicate increases in socio-economic developments in the villages around the habitat area have adversely affected the habitat quality and habitat rarity. This has resulted in a decline in biodiversity persistence, resilience, and breadth. It also has exacerbated the risk of declining species populations, potentially to extinction. Though focused on the Yunnan snub-nosed monkey, our approach toward the assessment of habitat quality and rarity over time based on species habitat suitability introduces a new perspective for assessing village development impacts on habitats for the conservation of other species.AbstractThe reduction in habitat quality (as shown, in part, by the increase in habitat rarity) is an important challenge when protecting the Yunnan snub-nosed monkey. We used the InVEST model to quantitatively analyze the dynamic changes in the habitat of the Yunnan snub-nosed monkey from 1975 to 2022. The results show that in the study period, the degree of habitat degradation increased, with the degradation range at its widest in the south, and the degradation intensity highest in the north, especially along a center “spine” area in the north. Over the latter part of the study period, the habitat quality of most monkey groups improved, which is conducive to the survival and reproduction of the population. However, the habitat quality and monkey populations are still at significant risk. The results provide the basis for formulating the protection of the Yunnan snub-nosed monkey and provide research cases for the protection of other endangered species.