Trends in biodiversity research in Brazilian marine protected areas

Marine protected areas (MPAs) are the main initiative for safeguarding biodiversity and ecological processes. However, their planning and effectiveness depend on a robust understanding of biodiversity patterns. We conducted a systematic review of the literature to investigate trends in biodiversity research within Brazilian MPAs. We evaluated the taxonomic groups studied, the diversity facets assessed (taxonomic, functional, and phylogenetic), the geographic distribution of studies, and the sampling approaches used. Of the 191 articles reviewed, 71% investigated a single diversity facet and while 29% considered both taxonomic and functional facets. Despite an increase in research over recent decades, the literature produced remains taxonomically and geographically biased. Most studies focused on fishes (58%) and taxonomic diversity (52%), while 20% addressed functional diversity, and phylogenetic diversity was virtually absent. Vertebrates were overrepresented, and studies were concentrated in fully protected MPAs and in Southeastern, Eastern, and Northeastern ecoregions. Most articles (93%) generated primary data, mainly through diver-based and imaging surveys. The limited integration across diversity facets may hinder a comprehensive understanding of ecological processes and effective conservation planning. We identify knowledge gaps and recommend expanding research efforts to underrepresented regions, taxa, and diversity facets. We encourage basic diversity research through species inventories for poorly known taxa and MPAs. Incorporating diversity facets will contribute to improving the ecological representativeness and resilience of Brazilian MPAs. • We conducted a systematic review of 191 studies on biodiversity in Brazilian marine protected areas • Research effort has grown, but shows strong taxonomic and regional biases • Most studies focus mainly on fishes and taxonomic diversity • Gaps remain for underrepresented taxa, regions, and diversity dimensions