Report on a remote swampy rock savanna, at the mid-Jari river basin, Lower Amazon

PIRES, M. J., 1992. Report on a remote swampy rock savanna, at the mid-Jari river basin, Lower Amazon . A wet rock-savanna habitat occurs in the Jari Ecological Station (IBAMA) in the mid-Jari basin, NW State of Pará, between the rivers Jari and Parü. The vegetation is classified in Portuguese as a 'campina rupestre'. It is characterized mainly by herbs and low shrubs, very few grasses and no trees. The plant community is a mixture of hydrophytes, xerophytes and amphibious plants, with several parasites and even a carnivorous Drosera. Such an assemblage is caused by the presence of water-filled pockets and canalets made by the differential erosion of the rock substrate, and the very dry exposed rock. Comparison of the plant species found in the Jari Eological Station savanna with others found in Amazon and Guiana showed many species in common and possible vicariants. The stress caused by this type of habitat favours the process of plant speciation. Evidence presented supports the idea of a floristic relationship between this area and the Guiana Highlands.