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Restoration ecology

Humans have deforested the land, stripped its surface to remove its mineral resources, exploited its grasslands and drained its wetlands, all to sustain the growing human population. Rivers have been straightened, diverted and dammed to provide humans with water, transportation, flood control, electric power and recreational facilities. However, when ecosystems are overexploited they degenerate. Healthy ecosystems are necessary in order to sustain the earth's soil, water and air resources. Some people feel that environmental degradation should be reversed through restoration ecology (i.e., the restoration of degraded environments to healthy ecosystems). However, the concepts involved are varied.

The modern concept of reclamation involves an attempt to return a damaged ecosystem to some kind of productive use that is socially acceptable. For example, a mined area might be converted to pastureland or an orchard. In this process rehabilitation of the mined area also occurs, making the land more visually pleasing. Historically, the term “reclamation” was used to describe the alteration of a native ecosystem to one of value to humans, such as the filling of a wetlands area in order to provide land for urban housing. Today, such an action might be considered environmental degradation. Because of the conflicting definitions, the use of the term reclamation can be confusing.

Sometimes, actions can be taken to avoid, reduce or compensate for the effects of environmental damage. Such mitigation efforts have been taken by the Army Corps of Engineers during construction projects. The native plants are removed from a site before construction begins and transplanted at a special holding site. After the construction project is completed, the native plants are restored using those from the holding site. Another example of mitigation might involve the creation or enhancement of wetlands in one area, in order to compensate for permitted wetland losses in another area. Mitigation often goes hand-in-hand with restoration. Texaco, in conjunction with environmental groups and the United States Fish and Wildlife Service, restored 500 acres of agricultural lands in the lower Mississippi Delta to bottomland hardwoods. Texaco received environmental credits for the mitigating effects of the new woodlands on air quality.

Restoration involves returning an altered or degraded site to its approximate condition before alteration. This includes restoring related physical, chemical and biological characteristics. Full restoration involves the complete return of a site to its original state. Restoring an ecosystem to its full productive health is not an easy task. It requires a broad interdisciplinary approach involving many different scientific fields of study (e.g., biology, ecology, hydrology and geology). Inherent in restoration projects are important though questionable and often unrealistic assumptions: historical environmental conditions can be recreated, existing ecosystems can be replaced, the physical environment can be altered in order to support the desired plants and animals, the desired plants and animals will become established, and the ecosystem will be able to sustain itself.

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Source:  OpenStax, Ap environmental science. OpenStax CNX. Sep 25, 2009 Download for free at http://cnx.org/content/col10548/1.2
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