Most orthents are found in very steep, mountainous regions where erodible material is so rapidly removed by erosion that a permanent covering of deep soil cannot establish itself. Such conditions occur in almost all regions of the world where steep slopes are prevalent. In
Australia and a few regions of
Africa, orthents occur in flat terrain because the
parent rock contains
absolutely no weatherable minerals except short-lived additions from rainfall, so that there is no breaking down of the minerals (chiefly
iron oxides) in the rock. The steepness of most orthents causes the
flora on them to be sparse shrubs or
grassland. In those on ancient, flat terrain,
dry grassland,
savanna, or rarely,
rainforest can prevail. Because of their extreme shallowness and, usually, steepness and consequent high erosion hazard, orthents are not suitable for arable farming. The flora typically supported on them is generally of very poor nutritive value for grazing, so that typically only low
livestock stocking rates are practicable. Many orthents are very important as
habitat for wildlife. ==See also==