Ecosystem engineer

An ecosystem engineer is any organism that creates, significantly modifies, maintains or destroys a habitat. These organisms can have a large impact on the species richness and landscape-level heterogeneity of an area. As a result, ecosystem engineers are important for maintaining the health and stability of the environment they are living in. Since all organisms impact the environment they live in in one way or another, it has been proposed that the term "ecosystem engineers" be used only for keystone species whose behavior very strongly affects other organisms

Jones et al. identified two different types of ecosystem engineers:

Allogenic engineers modify the environment (biophysical) by mechanically changing living or nonliving materials from one form to another. Beavers are the original model for ecosystem engineers; in the process of clearcutting and damming, beavers alter their ecosystem extensively. The addition of a dam will change both the distribution and the abundance of many organisms in the area.Caterpillars are another example in that by creating shelters from leaves, they are also creating shelters for other organisms which may occupy them either simultaneously or subsequently. An additional example may be that of woodpeckers or other birds who create holes in trees for them to nest in. Once these birds are through with them, the holes are used by other species of birds or mammals for housing.

Autogenic engineers modify the environment by modifying themselves. Trees are a good example, because as they grow, their trunks and branches create habitats for other living things; these may include squirrels, birds or insects among others. In the tropics, lianas connect trees, which allow many animals to travel exclusively through the forest canopy.

Being able to identify ecosystem engineers in an environment can be important when looking at the influence these individuals may have over other organisms living in the same environment – especially in terms of resource availability.

The presence of some ecosystem engineers has been linked to higher species richness at the landscape level. By modifying the habitat, organisms like the beaver create more habitat heterogeneity and so can support species not found elsewhere. Thoughts may be that similar to other umbrella species by conserving an ecosystem engineer you may be able to protect the overall diversity of a landscape. Beavers have also been shown to maintain habitats in such a way as to protect the rare St. Francis' satyr butterfly and increase plant diversity.

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