A pioneer organism is an organism that populates a region after a natural disaster or any other event that may have caused most life in that area to disappear. Common pioneer organisms include lichens and algae. Mosses usually follow lichens in colonization, but cannot serve as pioneer organisms. Pioneer organisms modify their environment and establish conditions under which more advanced organisms can live. In some circumstances, other organisms can be considered pioneer organisms. 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.