Designing wildlife crossing structures for ungulates in a desert landscape: A case study in China

摘要

This paper reports on the design of wildlife crossing structures (WCSs) along a new expressway in China, which exemplifies the country's increasing efforts on wildlife protection in infrastructure projects. The line and belt transect method, the surface water survey, and the sign-tracking investigation were used to determine the target species in the study area and the quantity, candidate locations, size, and type of the WCSs. The intensity index and encounter rate showed that the ibex (Capra ibex), argali sheep (Ovis ammon), and goitered gazelle (Gazella subgutturosa) are the main ungulates in the study area. Among them, the goitered gazelle is the most widely distributed species. Underpass WCSs were proposed based on the expert knowledge and crossing hotspots estimated using survey results. The mean distance between estimated hotspots and their nearest proposed WCSs is around 341 m. In addition, those proposed WCSs have a width of no less than 12 m and height of no lower than 3.5 m, which is believed to be sufficient for ungulates in the area. Given the limited availability of high-resolution movement data and wildlife-vehicle collision data during the road's early design stage, the approach demonstrated in this paper facilitates the practical spatial planning and provides insights into designing WCSs in a desert landscape.