Boundaries

This ecoregion includes all coastal drainage basins in eastern Brazil from the Rio Itabapoana drainage in the south to Rio Sergipe in the north. To the west it is limited by the drainage divide with the Rio São Francisco basin along the Serra do Espinhaço.

Topography

The rivers of this ecoregion drain the eastern slopes of the Serra do Espinhaço to the Atlantic Coast in a varied landscape crossing crystalline mountains, valleys, and sandstone plateaus. Substrates range from Precambrian basement rocks to Tertiary-Quaternary deposits of the Barreiras Formation (Dillenburg and Hesp 2009; Martin et al. 1996). Elevations extend from the flat coastal plain up to 2890 m asl at Pico da Bandeira, which is part of the Serra do Caparaó.

Freshwater habitats

The freshwater habitats range from low gradient slow current large rivers to steep headwater streams with fast waters.  Many coastal streams have mangroves associated to their estuarine areas. The low portion of the large rivers is dominated by soft substrate composed of sandy and muddy bottoms, while the mid-upper portions have extensive reaches of deep pool, riffles and rapids with gravel and boulders as the dominant substrate. The upper reaches alternate from bedrock (either granitic or sedimentary sandstones) to boulders and rocks, with many step pools and rapids.

Terrestrial habitats

Atlantic Forest, or Mata Atlântica, is the ecoregion’s dominant vegetation type. This is sub-divided into Atlantic coastal forests and Atlantic semi-deciduous and deciduous forests. The Atlantic coastal forests in this ecoregion are distinguished from other Atlantic forests by their unique set of endemics as well as similar structure and composition to Amazonian forests (WWF 2001). The seasonal forests further inland include a heterogeneous mix of semi-deciduous and deciduous forests, evergreen forests, and campo rupestre (high-altitude grassland). The Atlantic interior forests are bordered to the north by caatinga and to the west by cerrado. Restingas and mangroves line the coast.

Description of endemic fishes

More than 60% of species in the ecoregion are endemic, as well as eight endemic genera: Myxiops, Lignobrycon, Henochilus, Glaphyropoma, Wertheimeria, Nematocharax, Kalyptodoras, and Prorivulus. Twenty-three percent of endemics are characids, followed by loricariids (18%), rivulids (15%), and trichomycterids (15%).

Other noteworthy fishes

Anthropogenic changes have likely lowered freshwater fish diversity in the Rio Doce, which is currently dominated by widespread species that show high tolerances to environmental change and pollution (Marques et al. 2004).

Justification for delineation

The Northeastern Mata Atlântica falls within Gery’s (1969) East Brazilian faunal region and southeastern province and Ringuelet’s (1975) ríos costeros S.E. Brasil ichthyographic province. The ecoregion contains high endemism, including seven endemic genera.

Level of taxonomic exploration

Good