Spatially structured soil properties and climate explain distribution patterns of herbaceous-shrub species in the Cerrado

We evaluated the influence of soil properties, climate, and space on the distribution of herbaceous-shrub species in the Cerrado biome. We determined species composition, cover, and richness along 25 line transects in Cerrado (savanna-like vegetation) in three protected areas with different soil types and altitudes. Soil physicochemical properties, climate, and geographic coordinates were included in the analysis as species distribution predictors. We observed high species richness in all sites, especially in the Chapada dos Veadeiros National Park (PNCV) and the Brasilia National Park (PNB), with over 200 species each. Only 16% of the species were recorded in all sites, indicating high species turnover for Cerrado herbaceous-shrub layer. The transformation-based redundancy analysis indicated that differences in the herbaceous-shrub flora were associated with soil physicochemical properties and climate. Species composition was primarily influenced by higher annual precipitation for PNCV, by the highest clay content and soil pH for PNB, and by greater annual mean temperature for Terra Ronca State Park (PETER). Soil, climate, and their spatially structured fraction explained herbaceous-shrub species distribution in the Cerrado (43.6%). The spatial variation which is not correlated to the environment adds only 4.5% to the model. Taken together, our findings provide a basis for understanding the distribution patterns of herbaceous-shrub species across climate, soil, and geographic distance. These findings are critical for the development of strategies to protect biodiversity and endangered species in the Cerrado, especially in the region most threatened by deforestation (PETER).