Primary succession

Primary succession occurring over time. The soil depths increase with respect to the increase in decomposition of organic matter, and there is a gradual increase of species diversity in the ecosystem. The labels I-VII represent the different stages of primary succession. I-bare rocks, II-pioneers (mosses, lichen, algae, fungi), III-annual herbaceous plants, IV-perennial herbaceous plants and grasses, V-shrubs, VI-shade intolerant trees, VII-shade tolerant trees.
Primary succession on Rangitoto Island, New Zealand

Primary succession is the beginning step of ecological succession where species known as pioneer species colonize an uninhabited site, which usually occurs in an environment devoid of vegetation and other organisms.

In contrast, secondary succession occurs on substrates that previously supported vegetation before an ecological disturbance. This occurs when smaller disturbances like floods, hurricanes, tornadoes, and fires destroy only the local plant life and leave soil nutrients for immediate establishment by intermediate community species.[1]

  1. ^ Baldocchi, Dennis. "Ecosystem Succession: Who/What is Where and When" (PDF). Biomet Lab, University of Ohio, Berkeley. Retrieved 9 December 2015.