Unraveling the Effect of Proximity to the Shore on the Structure and Diversity of Herbaceous Vegetation on Coastal Sand Dunes

Restinga is a type of coastal ecosystem, shaped by intricate interactions between limiting biotic and abiotic factors. They play a vital role in global biodiversity maintenance and provide essential ecosystem services. Vegetation in coastal dunes adapts distinctly to environmental variations yet remains highly vulnerable to human activities and climate change, warranting a comprehensive understanding of its responses to diverse environmental conditions. This investigation focused on herbaceous restinga vegetation within potential microhabitats and beach distance scales, seeking to unveil their influence on plant species composition and distribution. The aim was to enhance our understanding of coastal dune patterns while identifying potential indicator species and microhabitats. We evaluated species coverage across 156 sample plots distributed over six transects at 26 distance scales, considering microhabitats and environmental factors. The analysis encompassed species coverage, richness, and composition concerning beach distance within each microhabitat. Results suggest that species richness correlated more strongly with microhabitat types than beach distance. Identification of specific microhabitats was aided by coverage and indicator species. Redundancy analysis highlighted terrain, soil exposure, and flooding as significant contributors to variations in plant community composition. Frontal dune areas and humid slack dunes stood out distinctly compared to other microhabitats. Our findings underscore the crucial role of local conditions—like flooding, terrain slope, and soil exposure—in shaping coastal plant communities and species selection. This study offers valuable insights into these ecosystems, pivotal for identifying microhabitats and indicator species, and for effectively addressing biodiversity conservation challenges amid global climate change.