Abstract: Road network is one of the key factors driving the intensification of regional land use and landscape pattern change. How to measure the relationship between road network construction and ecological protection is a hot research topic. Based on road network data of various grades in 2000, 2010 and 2020, alongside land use data from the years 2000, 2010, and 2020 in the Altai Mountains Nature Reserve, we explored the relationship between land use and landscape patterns within different distances from the road network by using buffer zone analysis, dynamic land use change analysis, and landscape pattern analysis. The results showed that: (1) Over the past 20 years, roads of all grades intensified changes in land use types to varying degrees, with the changes being particularly pronounced alongside lowergrade roads. (2) From 2000 to 2020, forest lands and grasslands were the main sources of other land categories along roads of different grades. Forest lands and grasslands were major contributors to waters and unused lands along roads of provincial and national roads (>6.84%), while they were major contributors to residential lands and unused lands along county roads, township roads, and alternate roads (>6.15%). (3) In the past 20 years, there was an increase in both patch area and patch shape index within the buffer zones of roads of all grades. The growth rate of patch area in buffer zones of lowergrade roads was higher than that of highergrade roads. Moreover, patch shape was more complex and the landscape fragmentation was more significant. Our results indicate that land use types on both sides of the lower-grade road have changed significantly and that forest lands and grasslands were greatly affected by road construction. In the future, road network construction should not only assess its impact on the ecological environment along the roads in advance, reducing the negative impacts on the ecosystems of the Altai Mountains Nature Reserve before and after the construction of the road network, but also establish a long-term monitoring mechanism to ensure timely management and control of ecological environment changes.

Key words: land use, buffer zone, landscape pattern, Altai Mountains Nature Reserve