There are two types of succession. The first is primary succession. Primary succession occurs in an area that has not been previously occupied by a community. Places where primary succession occurs include newly exposed rock areas, sand dunes, and lava flows. Simple species that can tolerate the often- harsh environment become established first. These organisms help enrich the soil, allowing other species to become established. The first organisms to appear in areas of primary succession are often mosses or lichens. These organisms are known as pioneer species because they are the first species present; pioneer species must be hardy and strong, just like human pioneers.
