The first species to colonize an ecosystem that is previously damaged or disrupted
Pioneer species is the first to colonize an ecosystem previously disturbed or damaged. For example, sand that has become barren is colonized by a pioneer species of lyme grass (Leymus arenarius). Another example is the colonization of a habitat that is formed from lava flows that solidified by pioneer species of plants (e.g. swordfern, Polystichum munitum and moss Racomitrium ericoides). A clearing of the land is another example of a disturbance on the ecosystem in which is colonized later by pioneer species of plants.
Pioneer species are typically hardy species that are able to withstand the effects of the disruption or damage on the habitat. Certain lichens and algae are ubiquitous species that can grow on diverse habitats and therefore are usually the common pioneer species, i.e. the first inhabitants, following a disturbance. Typically, the pioneer plant species are photosynthetic as the new habitat would likely have a soil with fewer nutrients and largely exposed to no other energy source but light energy. It is also more likely that the pioneer plant species employ wind pollination over insect pollination system. Furthermore, the mode of reproduction is generally asexual rather than sexual. Eventually, the pioneer species could contribute nutrients to the soil when they die and thereby provide a better habitat for secondary succession.