Diversity and floristic uniqueness of non-arboreal restingas of the Northern Coast of Bahia, Brazil

The Northern Coast of Bahia state (NCB) encompasses the northernmost stretch of the state coastline and harbors restinga ecosystems of exceptional biodiversity, ecological, and cultural importance. Despite previous floristic surveys, non-arboreal restingas remain under-sampled, limiting the understanding of their composition and ecological dynamics. This study aimed to document angiosperm diversity in these habitats and assess the distinctiveness of their floristic communities. Field surveys were conducted in the non-arboreal restingas of Mata de São João and Entre Rios municipalities. Specimens were collected, photographed, and deposited at the ALCB Herbarium. Data from nine other Brazilian restingas were included in similarity (ANOSIM) and clustering (UPGMA) analyses using beta diversity indices. A total of 245 species, 174 genera, and 76 families were recorded, with Fabaceae (28 spp.), Rubiaceae (18 spp.), and Myrtaceae (16 spp.) being the most representative families. The genera Chamaecrista, Myrcia, and Cyperus were the most species-rich. While Bahia’s floristic communities showed general similarity, the NCB restingas were markedly distinct from the southern coast, showing stronger affinities with Sergipe state restingas. This pattern suggests a phytogeographic block shaped by shared climatic and geomorphological conditions, as well as endemic species. Despite their richness, NCB’s non-arboreal restingas remain insufficiently studied and increasingly threatened by rapid anthropogenic expansion.