Gaoru Zhu

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.

In recent decades, the influence of climate change and human activities on the ecosystem services (ES) in the Qinghai–Tibet Plateau (QTP) has been extensively investigated. However, few studies focus on linear traffic corridor area, which is heavily affected by human activities. Taking the Golmud–Lhasa national highway corridor as a case, this study investigated the land-use and land-cover change (LUCC) and spatiotemporal variations of ES indicators using ecosystem indices of fractional vegetation cover (FVC), leaf area index (LAI), evapotranspiration (ET), and net primary productivity (NPP) from 2000 to 2020. The results indicated that LUCC was faster in the last decade, mostly characterized by the conversion from grassland to unused land. In buffer within 3000 m, the proportions of productive areas represented the increased trends with distance. In terms of ES variations, the improved areas outweighed the degraded areas in terms of FVC, LAI, and NPP from 2000 to 2020, mostly positioned in the Qinghai Province. In addition, FVC, LAI, and NPP peaked at approximately 6000 m over time. With regard to influencing factors, precipitation (20.54%) and temperature (14.19%) both positively influenced the spatiotemporal variation of FVC. Nearly 60% of the area exhibited an increased NPP over time, especially in the Qinghai Province, which could be attributed to the temperature increase over the last two decades. In addition, the distance effects of climatic factors on ES indicators exhibited that the coincident effects almost showed an opposite trend, while the reverse effects showed a similar trend. The findings of this study could provide a reference for the ecological recovery of traffic corridors in alpine fragile areas.

The rapid expansion in shipping traffic, oil tankers, and oil field exploration in coastal and marine areas has, inevitably, resulted in the occurrence of many oil spill accidents. Oil spill accidents, which cause serious socio-economic, health, and environmental risks in coastal and marine areas, are a global concern. An oil spill pollution risk distribution map, combining multiple spill sources, is an effective tool by which to identify high-risk areas, which may help decision-makers in adopting contingency response and integrated coastal management. However, the assessment of oil spill distribution and risk assessment has been restricted, due to their heavy dependence on laboratory experiments and model simulations lacking reliable shipping data, which often derive inaccurate mapping results. This study combines the automatic identification system (AIS) and other data to precisely quantify the spatial extent of accident risk in coastal China. Based on oil quantity, oil spill rate, and accident probability, the ship, oil storage tank, submarine pipeline, and oil platform accidents spill risk index is analyzed. Next, combined with the sensitive degree of a coastal area, considering environmental and social issues, the oil spill environmental risk index is calculated. The oil spill pollution risk level is classified into five categories based on the oil spill pollution risk index, namely the low-risk zone, relatively low-risk zone, moderate-risk zone, relatively high-risk zone, and high-risk zone. The relatively high oil spill environmental risk concentration zone is located in the Bohai Sea, inter-border area between the Yellow Sea and Bohai Sea, the Yangtze River estuary, south of the Taiwan Strait, and the Pearl River estuary. The high-risk zone in the Bohai Sea is 36,018 km² in area, with an average risk value of 32.23, whereas the high-risk area in the Pearl River estuary is only 14,007 km². The high-risk area proportions in Tianjin are 23.5%, while those in Fujian, Hainan, Jiangsu, and Guangxi are very low. The low-risk area proportion in Hainan Province is 62%, while the value in Tianjin is only 2.9%. This study will be helpful in assisting decision-makers in mapping the influence area of oil spills and adopting the important strategies and effective management and conservation countermeasures for ship accidents in the coastal areas of China.