Diversidade de macrófitas e caracterização isotópica de sedimentos em áreas úmidas no Litoral Norte da Bahia, Brasil

Abstract

The wetlands of the northern coast of the state of Bahia are fundamental ecosystems for biodiversity, carbon storage and regulation of the hydrological cycle of a region. However, these environments have been impacted by urban growth, uncontrolled tourism and climate change. The study aimed to analyze the biodiversity and characteristics of these areas, focusing on aquatic macrophytes and paleoenvironmental reconstruction based on sediment analysis. The research was carried out in three different locations: Busca-Vida, Guarajuba and Conde. Samples of macrophyte distribution and composition were taken using plots (1 X 1m) and some specimens were collected for analysis in herbaria for taxonomic identification at the species or genus level. Statistical methods were used to evaluate species distribution patterns. In addition, sediment cores were collected in Conde and analyzed using carbon-14 and elemental analysis for environmental reconstruction and identification of changes in vegetation over time. A total of 28 species of macrophytes were identified, distributed in 17 families. The environments presented different patterns of biodiversity, with Busca-Vida and Guarajuba showing greater species richness, while Conde, less impacted by urbanization, revealed distinct communities. The presence of certain species may indicate environmental impacts, such as eutrophication. The diversity patterns of macrophytes were analyzed from the perspective of metacommunities and this analysis revealed that biodiversity is influenced by local environmental factors and the dispersion of species. The best preserved sites presented greater stability in the composition of plant communities, while impacted areas showed greater variation in the structure of the vegetation. Based on the findings of the isotopic and carbon-14 analysis of the sediments, changes in the vegetation over the last few thousand years were revealed, demonstrating how the environment has undergone natural and anthropogenic changes. The research indicated that the increase in human occupation has accelerated the degradation of these wetlands. The study concludes that the wetlands of the North Coast of Bahia have great ecological diversity, but are facing increasing threats. The conservation of these ecosystems is essential to maintain their environmental services and ensure the ecological balance of the region.