This paper is the result of geological survey engineering.

Objective This study aims to investigate the differences in surface matrix structures among three bedrock formation types in the Jinsha River dry-hot valley and their influence on plant community patterns, which is of great significance for establishing ecological restoration goals and assessing land rehabilitation potential in fragile ecological regions.

Methods The surface matrix layers and plant communities in three formation types—clastic rock, carbonate rock, and granite—in the Yuanmou Basin, Yunnan, were studied. Integrated methods including eco-geological surveys, geospatial sampling, and statistical analysis were applied to compare the effects of spatial structural characteristics and physicochemical properties of the surface matrix on plant community structure across these formations.

Results Significant differences were observed in the surface matrix structures among the three formation types: In the clastic rock area, the surface matrix was dominated by topsoil-slope wash layer (average thickness: 82.4 cm) and topsoil-eluvial layer (average thickness: 74.7 cm) structures, with an average clay content of 22.5%. The plant community was primarily dominated by deep-rooted Quercus species (65.7%), with a species richness of 25.4 species/100 m².In the granite area, the surface matrix mainly consisted of topsoil-eluvial layer structures (average thickness: 41.5 cm), with a clay content of 18.5%. The dominant species was the shallow-rooted shrub Dodonaea viscosa (68%), and species richness was only 7.3 species/100 m².In the carbonate rock area, the surface matrix was primarily characterized by topsoil-bedrock layer structures (average thickness: 13.4 cm), with a clay content of 19.3%. The dominant species consisted of a mixed shrub community of deep-rooted Phyllanthus emblica (35%) and shallow-rooted Dodonaea viscosa (37%).

Conclusions The results indicate that the thickness, fracture development, and water retention capacity of the surface matrix, controlled by bedrock weathering processes, are key factors driving plant community diversity in the dry-hot valley. Based on existing geological maps, vegetation restoration strategies can be efficiently developed for the region: the clastic rock area is suitable for an ecological restoration model involving artificial soil preparation + tree planting, while the granite and carbonate rock areas are better adapted to a natural restoration-oriented conservation model for open forest-shrub-grass communities.