Towards the reference ecosystems for quartzitic campo rupestre: Floristic composition and soil relationships

The loss and fragmentation of tropical habitats, especially extreme megadiverse environments like the campo rupestre (rupestrian grassland), impacts biodiversity and ecosystem services essential to millions of people. The campo rupestre is a grassy ecosystem of the Cerrado biome, a center of endemism in Brazil with high floristic richness and environmental heterogeneity, where plants have developed multiple adaptive strategies and form a vegetation mosaic shaped by local soil and microhabitat conditions. However, this ecosystem has been under severe land use conversion, while signs of augmenting pressure from climate change are now recorded at faster pace. Thus, understanding the particularities of its multiple habitats is fundamental to define habitat specific references to guide conservation and restoration projects that lead to increased biodiversity. In this work, for the first time, we characterize the floristic composition of the shrub and herbaceous strata and related them to the edaphic characteristics of the four main habitats that form the campo rupestre mosaic: rocky outcrop, stony grassland, sandy grassland, and peat bog. A total of 12,000 m² of shrub layer (120 plots of 10 × 10 m) and 120 m² (120 plots of 1 × 1 m) of herbaceous layer were sampled. We recorded 257 species belonging to 47 different families, and also observed a high species turnover among the four different habitats. Furthermore, we identified species from both ends of the edaphic gradient of the four habitats and emphasized the importance of multiregional studies to evaluate the association among species and soils before implementing any restoration project. This study provides the knowledge base to build the reference ecosystems for the mosaic of campo rupestre habitat types.