Pioneer species

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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 livible 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. These species will die and break down after some time, making new soil for secondary succesion (see below), and nutrients for small fish and plants in water.

Pioneer species are often grasses such as marram grass, which grows on sand dunes. In more rocky and damp condidions, they are usually lichen

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 colonise such areas are:

Barren rock - blue-green bacteria,lichen

Barren sand - lyme grass, sea couch grass, marram grass

Salt water - green algae, eel grass, Salicornia townsendii and Spartina townsendii

Clear water - algae, mosses

Pioneer species in secondary succession

Pioneer species can also be found in secondary succession (an established ecosystem being reduced by an event such as a forest fire or a clearing), colonizing open spaces which previously supported vegetation quickly. Common examples include:

• Birch
• Fireweed
• Raspberry
• Heaths

Pioneering 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.

See also

• Ruderal

References

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