Primary Succession is the first process of Ecological Succession which is what turns an area with only rocks into a forest over an extended period of time. The first organisms that inhabit this area are pioneer species. Pioneer species are small plants and decomposers such as lichen and fungi. These organisms gradually break down the rock into soil, over a long period of time, making the ground better suited to hold other plants that are able to survive in this environment. Primary Succession can lead to Secondary Succession.