Pioneer species
From The Art and Popular Culture Encyclopedia
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Pioneer species are species which colonize previously uncolonized land, usually leading to ecological succession. They are the first organisms to start the chain of events leading to a livable biosphere or ecosystem. Since uncolonized land may have thin, poor quality soils with few nutrients, pioneer species are often hearty plants with adaptations such as long roots, root nodes containing nitrogen-fixing bacteria, and leaves that employ transpiration. Pioneer species will die creating plant litter, and break down as 'leaf mold' after some time, making new soil for secondary succession (see below), and nutrients for small fish and aquatic plants in adjacent bodies of water.
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Pioneer flora
Pioneer species are often grasses such as marram grass, which grows on sand dunes. In more rocky and damp conditions, they are usually lichen, and small ephemeral bunchgrasses and wildflowers in crevices.
The plants, or anything that has the system of a plant, will be specially adapted to the extremes that may be experienced, and once they have modified the environment may be out-competed by less specific plants, eventually leading to a climax community.
Examples of the plants and organisms that colonize such areas are:
- Barren rock - blue-green bacteria, lichen
- Barren sand - Lyme grass (Leymus arenarius), Sea couch grass (Agropyron pungens), Marram grass (Ammophila breviligulata)
- Salt water - green algae, Marine eel grass (Zostera spp.), Pickleweed (Salicornia virginica), and Cordgrass (hybrid Spartina × townsendii) and (Spartina anglica).
- Clear water - algae, mosses, Freshwater eel grass (Vallisneria americana).
Pioneer fauna
Pioneering fauna are not responsible for initial colonisation of an area, but will colonize an area only flora and fungi previously inhabited, leading the way for others. A good example of this is the Roe Deer.
Secondary succession and pioneer species
Pioneer species can also be found in secondary succession, such as an established ecosystem being reduced by an event such as: a forest fire, deforestation, or clearing; quickly colonizing open spaces which previously supported vegetation.
Common examples of the plants in such areas include:
- Birch - Betula spp.
- Fireweed - Epilobium angustifolium
- Raspberry - Rubus spp.
- Heaths - Ericaceae spp.
- Graminoids, forbs, and wildflowers - native, introduced, and invasive species: such as fire dependent seed, cone, and resprouter chaparral genera.
See also
