Abstract: Qilian Mountain National Park is an important ecological protection area in western China, with important ecological core function. Understanding the temporal and spatial variations of habitat quality of Qilian Mountain National Park is of practical significance for ecological environmental protection and sustainable development. Based on land use data from four periods (1990, 2000, 2010, and 2018), we used the InVEST model to quantitatively assess the spatial and temporal variations of habitat quality and habitat degradation in Qilian Mountain National Park. The results show that, from 1990 to 2018, land use in Qilian Mountain National Park was generally stable, manifested as the expansion of both forests and water bodies, along with the decreases of grassland and unused land. The changes were mainly contributed by the mutual transformation among grassland, forest land, and unused land. Overall, the habitat quality of Qilian Mountain National Park had been increased, with high quality in the east and low quality in the west. From the perspective of land types, forest land had the highest habitat quality, while unused land had the lowest. The habitat quality varied across different altitudes and slope grades. With the increases of altitude, habitat quality showed an upward but fluctuating trend, with the lowest habitat quality in altitude grade IV. With the increases of slope grade, the habitat quality presented a downward trend, which was the highest in slope grade I. At the same altitude and slope grade, habitat quality varied across different periods. The cold and hot spots of habitat quality were exhibited as “cold in west and hot in east”. The hot spots were mainly distributed in the central and eastern regions, while the cold spots were primarily distributed in the west. Thedegree of habitat degradation of Qilian Mountain National Park from 1990 to 2018 had a characteristic of first increasing and then decreasing. The degree of habitat degradation was spatially distributed in points, with a ring-shaped structure distributed along the edges of the middle and east of the study area.

Key words: InVEST model, habitat quality, spatiotemporal change, Qilian Mountain National Park.