Pioneer organism

A pioneer organism, also called a disaster taxon, is an organism that colonizes a previously empty area first, or one that repopulates vacant niches after a natural disaster, mass extinction or any other catastrophic event that wipes out most life of the prior biome.

After a natural disaster, common pioneer organisms include lichens and algae.

Birds are usually the first to inhabit newly-created islands, and seeds, such as the coconut, may also be the first arrivals on barren soil.

Since the resolution of the fossil record is low, pioneer organisms are often identified as those that lived within hundreds, thousands, or a million years of the extinction event.

For example, after the Permian–Triassic extinction event 252 million years ago, Lystrosaurus, a tusked therapsid, was considered a disaster taxon.

In the aftermath of a forest fire , pioneer organisms are among the first to colonize the area; visible at the right are pioneer plants which have begun growing in an area charred by fire.