LAUSR

Mattic epipedon, which has important ecological benefits such as water retention and soil conservation, plays a pivotal role in the ecological function of alpine meadows. Therefore, exploring the relationships between the mattic epipedon and environmental factors, as well as spatial distribution of the mattic epipedon at different developmental levels are essential to elucidating the role of alpine meadows in the plateau ecosystem. In this study, samples of mattic epipedon were collected in alpine meadows in the middle of Qilian Mountains and were classified into three developmental levels primarily based on root volume, followed by thickness and bulk density. The relationships between mattic epipedon and environmental factors, such as topography, vegetation, and climate, were analyzed. The support vector machine model was used to map the spatial distribution of the mattic epipedon. The results showed that areas with relatively low elevation, gentle slope, low slope position, and a north⁃facing aspect, which were highly related to high soil moisture content, had a higher occurrence htt p:/ /w ww .ec olo gic a.c n http: / / www.ecologica.cn probability of mattic epipedon at high developmental levels. Vegetation covering the mattic epipedon at higher levels was usually well⁃developed and composed primarily by Kobresia and other hygrophilous plants. A well⁃developed mattic epipedon existed where there was significantly higher mean annual temperature, whereas there were no significant differences in mean annual precipitation regarding the existence of mattic epipedon at different developmental levels. The distribution of the mattic epipedon was highly consistent with the distribution area of alpine meadows, although at a higher spatial resolution. Furthermore, this study presented the spatial distribution of mattic epipedon at different developmental levels.