General ecological aspects of the tropical scrub vegetation on rocky outcrops ("campo rupestre") of the Serra dos Carajás, Pará, Brazil, are discussed, with information on its floral composition, the associations of plant species with soil type and animals, and the geographical distributions of component plant species. The plant community studied is composed of a total of 232 species, mostly herbaceous, belonging to 145 genera and 58 plant families. The two most common families were Gramineae and Leguminosae, followed by Cyperaceae, Myrtaceae, Rubiaceae, Malpighiaceae, Euphorbiaceae and Compositae. Some families have arboreal species sporadically found in forest islands ("capões de árvores") or as isolated trees, such as Anacardiaceae, Rutaceae, Sapotaceae and Vochysiaceae. Some families are restricted in occurrence to areas where water accumulates, such as Begoniaceae, Burmaniaceae, Eriocaulaceae, Gentianaceae, etc. Some families occur only rarely, such as Acanthaceae, Annonaceae. Chrysobalanaceae, Palmae, Sterculiaceae, etc. It appears that the most common pollinators in the area are bees. Other animals are also associated with the plants of this community, such as tabanid horseflies, reptiles and birds. The soil on which this plant community is based, besides having a very thin organic layer associated with mosses and lichens, has a large number of termite nests, in the transition from dry to rainy season. The biological preservation of the study area is justified by the large number of endemic species (for example, Ipomoea cavalcantei Austin), new species (for example, Erytroxylum nelson-rosae Plowman), species with potential as sources of drugs (for example. Pilocarpus microphylus Stapf. ex. Wardleworth), and ornamental plant species (for example, Vellozia glochidea Pohl), all of which belong to this community whose associated animals and soil types are yet so poorly researched.
Tropical savannas; Phytosociology; Phytogeography; Mining; Amazon; Brazil