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Thursday, November 13, 2008

Ecosystem restoration

Humans depend greatly on ecosystem services. These services vary greatly and include such things as erosion control, water and air purification, food, recreation, a list that could go on endlessly. To put things into a sharper perspective, at this point in time, we need ecosystems for our continued survival. There are many reasons to restore ecosystems, some include: restoring natural capital (i.e. goods and services), mitigating climate change (e.g. through carbon sequestration), helping threatened or endangered species recover, and aesthetic reasons (Harris et al. 2006, Macdonald et al. 2002). There are also moral reasons to restore ecosystems. Some would say that we have degraded, and in some cases destroyed, many ecosystems so it falls on us to ‘fix’ them. There is also the dissenting opinion that ecosystem restoration is not a valuable use of our time. Reasons for this opinion can include: restorations are not economically feasible; they don’t always work; they are expensive (money could be put to better uses); and that ecosystems naturally change over time and can recover by themselves.

The problem is that we cannot restore an ecosystem to the exact same state it was in before we disturbed it. This is because, as Anthony Bradshaw claims, “ecosystems are not static, but in a state of dynamic equilibrium…. [with restoration] we aim [for a] moving target.”

Even though an ecosystem may not be in its original state, the functions of the ecosystem (especially ones that provide services to us) may be more valuable than its configuration (Bradshaw 1987). One reason to consider ecosystem restoration is to mitigate climate change through activities such as afforestation. Afforestation involves replanting forests, which remove carbon dioxide from the air. Carbon dioxide is a leading cause of global warming (Speth, 2005) and capturing it would help alleviate climate change.

Problems with Restoration

Many people take the view that ecosystem restoration is impractical. One reason for this view is that restoration of ecosystems does not always work. There are many reasons for restoration failure. Hilderbrand et al. (2005) point out that many times uncertainty (about ecosystem functions, species relationships, and such) is not addressed, and that the time-scales set out for ‘complete’ restoration are unreasonably short. Other times an ecosystem may be so degraded that abandonment (allowing an injured ecosystem to recover on its own) may be the wisest option (Holl, 2006). Other negative impacts of ecosystem restoration can include the introduction of large predators, which may inspire doubts in people’s safety, and plants, some requiring disturbance regimes such as regular fires (MacDonald et al. 2002). High economic costs can also be a perceived as a negative impact of the restoration process. Public opinion is very important in the feasibility of a restoration; if the public believes that the costs of restoration outweigh the benefits, then support for that project is unlikely to be big, especially in small towns (MacDonald et al. 2002). In these cases people might be ready to follow the abandonment route and let the ecosystem recover on its own, which can sometimes occur relatively quickly (Holl, 2006).

Many failures have occurred in past restoration projects, many times because clear goals were not set out as the aim of the restoration. This may be because, as Peter Alpert says, “people may not [always] know how to manage natural systems effectively”. Also many assumptions are made about myths of restoration such as the carbon copy, where a restoration plan, which worked in one area, is applied to another with the same results expected, but not realized (Hilderbrand et al. 2005).

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