Geographic coverage, taxonomic coverage, habitats diversity & functional forms
Brazil has 17 geopolitical states along its coastline and they were all included in this synthesis (Table 2). The geopolitical state with the largest number of articles reporting at least one sample site inside its borders was the Rio de Janeiro (48%, 93 studies), followed by São Paulo (46%, 89 studies) and Bahia (44%, 86 studies). The least sampled states were Piauí (4%, eight studies), Sergipe and Amapá (6%, 12 studies). Only 16 high-ranked taxonomic groups were identified in all articles (Fig. 3B). The state with the largest number of studied taxa was São Paulo with 14 taxa followed by Rio de Janeiro (13 taxa) and Santa Catarina (12 taxa). The states with the smallest number of sampled taxa were Amapá and Alagoas with only 4 taxa each (Table 2).
Three taxa presented sample sites located within only one state: otaries (Rio Grande do Sul: Artico et al., 2010), echinoderms (Rio de Janeiro: Calderón, Ventura, Turon, & Lessios, 2010; Duarte, Ventura, & Silva, 2016; Pazoto et al., 2018; Wangensteen, Turon, Pérez-Portela, & Palacín, 2012), and Kinorhynchs (São Paulo: Randsø, Domenico, Herranz, Lorenzen, & Sørensen, 2018). Together with flatworms (= Platyhelminthes, Marigo et al., 2015), phylogeographic studies targeting these taxa concentrated their sampling in the southern Brazil (> 21° S). Fishes and mollusks presented the most comprehensive and spatially widespread sampling across Brazil (100% states), followed by crustacean (16/17 states), and plants (14/17 states). Fishes were the most studied taxon encompassing 32% of all studies, followed by crustaceans (21%) and mollusks (10%) (Fig. 3B). Of all studied taxa, 49% were invertebrates, followed by 47% of vertebrates, and 4% plants, including algae (Fig. 3C). Regarding habitat, 63% studies targeted benthic species, 34% pelagic, and 3% aerial (i.e. coastal and marine birds) (Fig. 3D).