Flexi Says: Typically, living things will begin to grow on a volcano after it goes dormant. This occurs by the ecological process of primary succession. Generally, the area is nothing but bare rock after a major eruption. The first species to colonize a disturbed area such as this are called pioneer species. They change the environment and pave the way for other species to come into the area. Pioneer species are likely to include bacteria and lichens that can live on bare rock. Along with wind and water, they help weather the rock and form soil. Once soil begins to form, plants can move in. At first, the plants include grasses and other species that can grow in thin, poor soil. As more plants grow and die, organic matter is added to the soil. This improves the soil and helps it hold water. The improved soil allows shrubs and trees to move into the area.