Primary succession is a naturally occurring ecological process that begins on bare rock or soil that has never been colonized. This process of ecological succession is initiated by the arrival of pioneer species and involves a progression of species that eventually results in the development of a stable community. As the pioneer plants such as lichens and mosses start to decompose and break down the rock or soil, it creates conditions that are more favorable for other plant species to thrive. Over time, secondary succession may occur, whereby the pioneer species are replaced by more established plant communities. Primary succession is an important process in ecosystem development and helps to support the growth and diversity of plant and animal life.