Ecological effects of the road and railway in the Golmud-Lhasa section of the Qinghai-Tibet traffic corridor

Abstract

The Qinghai-Tibet corridor includes road and railway in the highland area, characterized as the highest altitude, longest route and various sensitive ecosystems. Quantitative analysis of ecological effects along the Qinghai-Tibet corridor is critical to understand the impact of different traffic infrastructure on global hotpot of biodiversity maintenance. In this study, the Golmud-Lhasa national highway, railway and expressway were selected to analyse the impact of buffer zone and the pattern of landscape, thereby clarify the land use change, vegetation dynamics and landscape change. The results showed that the dominant type of grassland decreased and unused land increased in 2020 within the national highway buffer zone. As for railway station buffer zone, dominant grassland and unused land decreased while construction land increased in 2020. In buffer zones of national highway, there were contrary trends in cropland across periods, which decreased in 2000 and 2020 while increased in 2010; in different periods, the proportion of forest, water body and unused land increased, while the proportion of shrubland and construction land decreased, and waterbody and grassland were increased obviously within 0-3000m. In buffer zones of railway station, there were threshold effects in each land use types alongside distance gradients, in details, the threshold of grassland, shrubland and unused land was about 8000m. The vegetation status in the national highway and railway station buffer zone were improved over time, especially in the buffer zone of railway stations in 2010 and 2020. The results of landscape pattern index showed that although the highway construction caused the increased landscape fragmentation, it also improved the diversity and evenness of landscape. Therefore, the future expressway construction should be aimed at improving connectivity and maintaining stability.