Floristic and structural diversity of riverine forest remnants in the Pampa biome

Abstract Riverine forests have high floristic diversity and are heterogeneous, even when they are near each other. Therefore, we aimed to compare three riverine forest remnants of Southern Brazil located in the Pampa biome regarding floristic and structural biodiversity, to: i) check whether the studied forest fragments maintain heterogeneity and high floristic richness as seen in riverine forests, even when close to each other, and ii) indicate the predominant successional groups in each remnant. A total of 81 sampling units were established, and all trees with diameter at breast height ≥ 15 cm were measured. We sampled 1,659 individuals, 67 species, and 34 families. The richness and structure of the three communities differed, confirming the high heterogeneity of riverine forests. One of the remnants had a higher predominance of pioneer species and individuals, which differentiated it from the other two. The latter, in turn, showed higher similarity in floristic and structural composition, with a predominance of secondary and late successional individuals and species. Differences in soil moisture, in the size and shape of fragments may be factors that contributed to the floristic and structural diversity observed. The remnants, although small and surrounded by monocultures, are heterogeneous and important for biodiversity conservation.