Multidisciplinary assessment of a restored mangrove ecosystem in Guanabara Bay, Brazil: Linking science and conservation

Abstract Mangrove ecosystems, due to their coastal location, are particularly vulnerable to anthropogenic disturbances of varying intensity and origin. These disturbances can lead to a loss of original mangrove cover, biodiversity decline, and a degradation of their ecological functions. This study examines a restored mangrove area within the Barão de Mauá Natural Municipal Park (PNMBM) in Guanabara Bay, Brazil, two decades after the initiation of a restoration project. We employed a multidisciplinary approach, utilizing a combination of genetic diversity analysis of two mangrove species, phytosociological assessment of the area's vegetation structure, and remote sensing techniques. While genetic diversity did not reveal significant differences between adult and seedling populations across the restored area, overall diversity remained low. We found a strong degree of genetic erosion, particularly in Laguncularia racemosa. Notably, L. racemosa exhibited higher abundance, with greater density and dominance compared to the other species for both adult and seedling populations. Remote sensing data indicated high Normalized Difference Vegetation Index (NDVI) values following the completion of the restoration project. These findings suggest that the PNMBM has demonstrated remarkable resilience in maintaining its vegetation cover. However, further time may be necessary for the genetic and phytosociological structure to fully recover and achieve a robust, successful stage of development with improved genetic and ecological diversity. This interdisciplinary approach aimed to address existing knowledge gaps and provided valuable insights to inform the management of the PNMBM and guide future restoration efforts.