The Sanctuary is located in a transitional strip between dry and very dry tropical forest developing in an area which has a very long period of drought, in which the majority of plants loose their foliage. During rainy season the forest regains its foliage and exuberance. The visitor can find diverse vegetation around the estuaries, consisting mainly of several species of mangrove (Avicennia germinans, Conocarpus erectus, Laguncularia racemosa and Rhizophora mangle) that play an important role since they serve as nursery and refuge to different species.