Factors controlling distribution of mountainous gullies at the regional scale: An example of the Yuanmou dry-hot valley (SW China)

The primary factors controlling regional gully distribution in mountainous areas are poorly understood. To investigate the spatial characteristics and controlling factors of mountainous gullies at the regional scale, kernel density (KD) estimation, semivariogram, and Geodetector methods were used based on 11 environmental factors of gullies in the Yuanmou dry-hot valley. The results show that (a) gullies are widely but unevenly distributed in the valley, with an average KD of 1.155 km/km2, and gully distribution displays spatial autocorrelation with environmental factors over diverse scales; (b) relief amplitude (Ra), landform type, and slope are the primary factors controlling gully distribution, and land use type, precipitation, and elevation are also important factors; and (c) a high risk of gully erosion occurs in areas with an elevation of more than 1437 m, slope greater than 15°, and Ra greater than 173 m, with grassland vegetation or luvisols and cambisols soil types. These results will not only help to understand the spatial pattern and formation mechanism of gullies at the macroscopic scale but also provide a scientific reference for regional gully management.