Effects of transport infrastructures and climate change on ecosystem services in the integrated transport corridor region of the Qinghai-Tibet Plateau

The ecosystem services of the Qinghai-Tibet Plateau have been hot topics in recent decades due to their unique value, and the region's sensitivity to climate change and human activities is considered to be of major importance. However, few studies have focused on the variations of ecosystem services in response to traffic activities and climate change. This study applied different ecosystem service models, along with the buffer analysis, local correlation and regression analysis to quantitatively analyze the spatiotemporal variations of carbon sequestration, habitat quality, and soil retention, further detected the climatic and traffic influences in the transport corridor region of the Qinghai-Tibet Plateau from 2000 to 2020. The obtained results showed the following: (1) The carbon sequestration and soil retention increased over time, while the habitat quality decreased during the railway construction period; in addition, the variations of ecosystem services between the two periods exhibited substantial spatial differences. (2) The distance trends of ecosystem service variations were similar for the railway and the highway corridors, and the positive ecosystem service trends were mainly observed within 2.5 km and 2 km of railway and highway corridors, respectively. (3) The impacts of climatic factors on ecosystem services were predominantly positive; however, temperature and precipitation displayed contrasting distance trends in their impacts on carbon sequestration. (4) The types of frozen ground and locations away from the railway or highway were the combined factors affecting the ecosystem services, among which carbon sequestration was negatively influenced by the distance from the highway in the continuous permafrost areas. It can be speculated that rising temperatures caused by climate change may intensify the decline of carbon sequestration in the continuous permafrost areas. This study provides guidance on ecological protection strategies for future expressway construction projects.