Objective Conducting habitat quality assessments not only elucidated ecological environment changes and their driving factors, but also provided a scientific basis for improving habitat quality. The northern nature reserves of the Altay region, located in the heart of the Eurasian continent, played a significant ecological role with their prominent forest niches. These reserves constituted a crucial natural green barrier, influencing the socio-economic development of not only the Altay region but also northern Xinjiang. Evaluating the changes in habitat quality and its driving factors in these reserves will facilitate the development of the effectiveness strategies for the future preservation of ecological security in the Altay region.

Methods Based on three periods of land use data from 2000, 2010, and 2020, this study integrated the InVEST model with the Geodetector model to assess the habitat quality of the northern natural protected areas in the Altay region over the past two decades. The study analyzed the spatial distribution characteristics of habitat quality and its influencing factors in the study area.

Results (1) From 2000 to 2020, there was a reduction in the area and proportion of forest, grassland, and water bodies, while the cropland and unused land increased, with the most significant increase occurring in the unused land. The predominant land use transition during this period was from forest and grassland to unused land. (2) Over the 20-year period, highly suitable habitat areas exhibited the largest proportion, with habitat quality maintaining a high degree of stability. The spatial extent of habitat improvement exceeded that of habitat degradation, suggesting an overall enhancement in habitat quality, which remained at a relatively high level. (3) Habitat quality exhibited a strong positive spatial clustering effect, with the Moran’s I index initially decreasing and then increasing from 2000 to 2020, indicating a trend of initial decline followed by an increase in clustering intensity. (4) The Geodetector model was employed, conducting both univariate and interactive analyses of driving factors for habitat quality changes. Univariate analysis identified GDP, elevation, and land use intensity as the primary factors influencing habitat quality from 2000 to 2020. A comprehensive interaction analysis revealed that GDP, elevation, and the normalized vegetation index, among other factors, exerted s substantial influence on habitat quality changes in combination with other factors.

Conclusions From 2000 to 2020, the overall habitat quality of the northern natural protected areas in the Altay region remained at a relatively high level, showing a slight upward trend. Areas with high habitat suitability accounted for a large proportion, and the ecological pattern exhibited relatively stable. However, the continued reduction in forest and grassland areas, along with the significant expansion of unused land, indicated that some areas still faced risks of ecological degradation. The evolution of habitat quality was jointly driven by natural geographic conditions and human activities, with economic development, elevation, and land use change emerging as key influencing factors. To further maintain and enhance the ecological barrier function of the region, it is essential to strengthen land use regulation, control the unregulated expansion of unused land, and promote the implementation of the “ecological priority” principle in regional development, thus achieving a better balance between nature conservation and sustainable development.