Impact of road network expansion on landscape ecological risk and soil erosion sensitivity on the Luochuan Tableland of the Chinese Loess Plateau

Road construction efforts have significantly increased in developing countries in recent decades. While expanding road networks have promoted economic development, it may result in the fragmentation of ecological landscapes and an increased risk of soil erosion. However, knowledge about these consequences is limited. This study aimed to characterize the expansion of the road network, landscape ecological risk, and soil erosion sensitivity on the Luochuan tableland of the Chinese Loess Plateau from 1990 to 2020. In this study, the landscape ecological risk refers to the spatial and temporal heterogeneity within a region, as well as the scale effect and the impact of landscape pattern fragmentation on regional ecological risk. The results of this study showed that 1) the road network on the Luochuan tableland has significantly expanded over the past 30 years, and the proportion of areas with high road density (kernel density value > 120 km/km²) increased from 10.13% to 37.18% of the total area between 1990 and 2020. 2) The landscape ecological risk was the highest in 2005; from 1990 to 2005, the land area with extra-high landscape ecological risk increased from 0 to 13.30 km² and then decreased to 0 in 2020. 3) Similar to the variations in landscape ecological risk, the soil sensitivity was severe in 2005 on the Luochuan tableland. 4) Areas with a higher landscape ecological risk were mainly concentrated in areas of high road density. The road kernel density was significantly and positively correlated with landscape ecological risk and soil erosion sensitivity (P < 0.01). This study could help to understand the potential impact of road network expansion on landscape ecological risk and soil erosion at a regional scale.