Ecological vulnerability and influencing factors along an expressway in the agro-pastoral ecotone of northern China: a case study of the Su-Hua expressway

Due to economic development, the construction of expressways has increased. This study used gross primary productivity (GPP) data from 2010 to 2021 to assess the ecological vulnerability along the Su-Hua Expressway. The geographical detector method was used to analyze the spatiotemporal variations in ecological vulnerability and its drivers in a 2000-m buffer zone around the Su-Hua Expressway. The goal was to provide crucial information for regional environmental monitoring and management along expressways in the agro-pastoral ecotone of northern China. The following was observed. (1) Ecological vulnerability was relatively high from 2010 to 2021, with 36.5% of the region experiencing an increase before and 86.3% after road construction. (2) Human activity and natural factors were the primary factors influencing ecological vulnerability. The key environmental factors were annual mean precipitation, elevation, annual mean temperature, slope, and land use type. Expressway construction and converting farmland to grassland were the dominant human activities. (3) The ranking of the influencing natural factors was mean annual precipitation > elevation > temperature > slope > land use type. Expressway construction increased the mean value of ecological vulnerability by 0.59. Human activities had adverse effects on the environment.