In recent years, highway construction in the Qinghai-Tibet Plateau (QTP) has developed rapidly. When the highway passes through grassland, the soil, vegetation, and ecological environment along the line are disturbed. However, the impact on soil bacteria is still unclear. Soil bacteria play an important role in the ecological environment. The Qinghai-Tibet Highway (QTH) was selected as the research object to explore the changes in bacterial community structure, vegetation, soil, and other indicators. The results showed that the highway-related activities increased the degradation of vegetation along the road, significantly changed the physical and chemical properties of soil, and caused heavy metal pollution. These environmental factors affected the diversity and community structure of soil bacteria. This kind of disturbance shows a trend of gradually increasing from near to far from the highway. Gemmatimonas, Terrimonas, Nitrospira and Bacillus are more tolerant to environmental changes along the highway, while Barnesiella, and Blastococcus are more sensitive. The content of nitrate decreased and the content of ammonium nitrogen increased in the disturbed area, increasing the abundance of nitrifying bacteria. Therefore, the main factor of the disturbance of the QTH on the grassland is the decline of soil nutrient content, and the supplement of soil nutrients such as carbon and nitrogen should be taken into account in the process of ecological restoration of grassland along the line.

Road mortalities caused by wildlife–vehicle collisions (WVCs) are the most obvious negative effect of roads on wildlife. Identifying the influencing factors and summarizing the spatial-temporal patterns of WVCs have been important research trends in recent decades. However, most studies have only considered a portion of the factors, and there remains a lack of a relatively complete framework, including the numerous factors of WVCs, as well as the underlying transmission mechanisms between factors. In this study, an analytical framework incorporating a wide range of previously discussed factors is constructed. The framework not only displays the possible direction of the influence of each factor on WVCs, but also summarizes some important potential explanations under some circumstances and reveals the main interactions between certain types of factors. From one perspective, the factors affecting WVCs can be divided into four categories: species characteristics, road and traffic characteristics, landscape and environmental characteristics, and driver-related factors and specific human activities. From another perspective, the factors affecting WVCs can be mainly categorized as those related to entering roads and those related to leaving roads safely. The study begins with a discussion of three important sub-frameworks: factors promoting road crossing, factors related to barriers to movement, and factors related to safe crossing. Finally, a suggestion is provided to promote the research on WVCs globally.

The spatial aggregation patterns of wildlife-vehicle collisions are used to inform where mitigation measures are most needed. Based on 10 years of observations of vertebrate roadkill on the Ring Changbai Mountain Scenic Road, the spatial distribution characteristics of roadkill incidence were analyzed in this study. Using the field survey method to investigate roadkill incidents and their influencing factors, we applied generalized linear mixed modeling (GLMM) for model selection and constructed roadkill models for different taxa groups. The spatial distribution patterns of roadkill hotspots vary among different taxa and exhibit a unimodal or multimodal distribution. The road section along a river and with a minimal distance between the road and the water has a high incidence of roadkill. The density of roadkill for various taxa decreases as the distances from rivers, bridges, and ponds increases. However, there appears to be no correlation between the density of bird roadkill and any factors. Finally, wildlife crossing facilities and guidance measures aimed at reducing the incidence of roadkill and enhancing the selection of routes and wildlife crossing structures in the area are formulated.

Wildlife crossing structures (WCSs) are an important measure to protect biodiversity and reduce human-wildlife conflict, especially for bundled linear infrastructure. The aim of this study was to evaluate two “management and behavioral” factors (salt blocks and feces) in relation to two “structural factors” (underpasses’ dimension and distance of bundled linear infrastructure) along Qinghai-Tibet bundled linear infrastructure (Qinghai-Tibet railway alignment runs parallel to the Qinghai-Tibet highway) and Gonghe-Yushu bundled linear infrastructure (Gonghe-Yushu expressway is parallel to the Gonghe-Yushu highway) using infrared cameras. Eight underpasses were monitored in the Qinghai-Tibet railway and six in the Gonghe-Yushu expressway, with half of the induced experimental group and half of the control group in each area. The monitoring shows that the Qinghai-Tibet railway area has richer species diversity than the Gonghe-Yushu expressway area. Salt block and feces induction experiments showed that the relative abundance index (RAI) of the experimental and control groups did not reveal significant differences in both areas. In addition, we found that the wider the width of the underpasses, the higher the utilization rate of kiang (Equus kiang) and wolly hare (Lepus oiostolus). And the distance from the adjacent linear infrastructure was positively correlated with the frequency of wolly hare, while no correlation was found with other species. In summary, this study found that salt block and feces induction could not improve the utilization rate of ungulates to underpasses of bundled linear infrastructure on Tibetan Plateau, and preliminary understood the factors affecting the utilization rate of underpasses.