Floristic survey on rocky outcrop in a seasonally dry tropical forest

Rocky outcrops function as island-like environmental filters and pivotal ecological refuges for local and regional biodiversity, with their inherent topographic and microclimatic dynamics directly shaping vegetation composition and distribution across slopes. This study inventoried the flora of a rocky outcrop slope within Brazil's Caatinga biome, a seasonally dry tropical forest, to analyze species distribution patterns and their relationship with microtopographic conditions. The slope was stratified into base, middle and top segments according to slope gradient, with specimens collected over seven months of field expeditions, followed by taxonomic processing to compile a floristic inventory. The survey documented 60 species, 53 genera, and 28 families, with Fabaceae, Euphorbiaceae, and Malvaceae emerging as the most representative families; herbaceous species dominated, followed by trees and shrubs. Species richness declined along the topographic gradient as altitude increased, with 43% of flora comprising species widespread across Brazilian biomes and 20% endemic to the Caatinga. Variations in species distribution across slope positions suggest that topographic heterogeneity may drive distinct pedological and microclimatic conditions, directly influencing vegetation dynamics in rock outcrops. These findings underscore the role of microtopography in structuring plant communities in harsh environments