Forces driving the regeneration component of a rupestrian grassland complex along an altitudinal gradient

This study aimed to document variation in the composition and structure of regenerating woody vegetation along an altitudinal gradient of a rupestrian grassland and to describe the relationship between species and characteristics of the soil. All woody plants with a diameter at ground height of ≤1 cm were collected in seven sampling sites at altitudes between 800 and 1400 m in Serra do Cipó (Minas Gerais State, Brazil). Phytosociological parameters and the Shannon diversity index were calculated and compared using Hutcheson’s t test. Floristic composition was evaluated by nonmetric multidimensional scaling (NMDS) ordination with analysis of variance as a confirmatory analysis, in which the response variables were the axis of the NMDS. Correlation between soil characteristics and vegetation patterns was evaluated with multiple regression models and canonical redundancy analysis. For all analyses, we performed analysis of variation partitioning to decompose the explanation of spatial, soil, and altitudinal variation. A total of 809 individuals of 127 species belonging to 26 families were sampled. Species richness and structure varied among altitudes. Species diversity followed an altitudinal pattern and was higher at lower altitudes. Some soil variables, such as remaining phosphorus, base saturation, and structural components, were more strongly correlated with species distribution than the others. Although variation in altitude leads to changes in the composition of the regenerating woody species, variation in plant communities was determined by a combination of environmental factors, of which soil properties played an important role.