Abstract This study evaluated the effectiveness of Federal Protected Areas on the coast of the state of Paraíba in northeastern Brazil with regard to the preservation of mangrove forests. The study area encompassed remaining mangrove forests distributed in four federal protected areas (PAs) located in Paraíba: Area of Relevant Ecological Interest (AREI) of Mangroves of the Mamanguape River, Environmental Protection Area (EPA) of the Mamanguape River, the Restinga de Cabedelo National Forest (NATFOR), and the Acaú-Goiana Extractive Reserve (EXTRES). The methods consisted of a spatiotemporal analysis considering the year of creation of each PA, with mapping and quantification as well as the assessment of impacts and effectiveness. NATFOR and EXTRES had the most conserved mangrove areas on the temporal scale, whereas AREI and EPA had the largest reductions in areas of mangrove forest. Urban expansion, sugarcane monoculture, and shrimp farming represented the main negative impacts spatially identified in these PAs. Based on the results of this study, the mangrove forests analyzed have continually suffered anthropogenic pressures since their creation as protected areas. The greatest effectiveness in the preservation of mangrove forests was found in Acaú-Goiana EXTRES and the least effectiveness was found in the AREI of Mangroves of the Mamanguape River.

O presente artigo apresenta os primeiros dados populacionais sobre a rara angiosperma marinha Halophila baillonis. A população está localizada em uma área protegida por recifes com profundidade média de 5m, cobrindo uma área de 12000m2 (400 m de comprimento por 30 m de largura, paralela a linha de praia). A população apresentou, em geral, menores densidades de hastes e valores de biomassa durante a estação chuvosa com diferenças significativas entre estações do ano registradas, apenas, para biomassa aérea. Apesar deste novo registro a espécie continua a ser considerada rara na costa brasileira.

The present paper presents the first population data for the Southern Hemisphere of the rare seagrass Halophila baillonis. The population studied is located in a calm, reef-protected area at depths ≤ 5 m, covering 12,000 m2 (400 m long by 30 m wide, oriented parallel to the coastline). The population generally demonstrated low shoot density and biomass during the rainy season, with significant differences between seasons, being found only for aboveground biomass. Despite the identification of this new population, the species continues to be considered rare along the Brazilian coast.