What are the stages of primary succession?

Primary succession begins with newly formed land such as bare rock of volcanic island.  Pioneer species such as lichens and mosses colonise the rock. When these pioneer species die organic matter builds up which helps with soil formation.  Soil formation allows grasses and small herbaceous flowering plants to colonise. The presence of plant roots reduce soil erosion by increasing the stability of the soil.   As plants die more organic matter builds up creating deeper soil which allows larger plants and shrubs to colonise.   These larger plants create shade which causes decrease the number of pioneer species but an increases in biodiversity.  Increasing diversity of plants subsequently increases the diversity of consumers.  Eventually trees colonise and a climax community forms (A climax community is the stable final stage of ecological succession)