[3] The vegetation is in the transition between the Amazon and Cerrado biomes, and includes coastal marine influence, covering a large area of lacustrine basins.

[5] Other bird species include striated heron (Butorides striata), black-bellied whistling duck (Dendrocygna autumnalis), great egret (Ardea alba), ringed kingfisher (Megaceryle torquata), blue dacnis (Dacnis cayana), rufescent tiger heron (Tigrisoma lineatum), white-faced whistling duck (Dendrocygna viduata), Neotropic cormorant (Phalacrocorax brasilianus) and white-winged swallow (Tachycineta albiventer).

The objective is to regulate use and occupation of the land, exploitation of natural resources, fishing, predatory hunting and breeding of buffalo, so as to preserve biological integrity, water quality and refuges for migratory birds.

[8] Ordnance 66 of 5 November 2012 assigned an area of 56,386.11 hectares (139,333.1 acres) to SEMA/MA as the Baixada Maranhense sustainable use conservation unit.

Issues include construction of fish farming tanks, accumulation of solid waste and predatory hunting of wattled jacana and American purple gallinule.