Difficulties Of Ecological Restoration
For a number of scientific reasons, it is difficult to undertake management actions in restoration ecology. One important problem is that there is usually an imperfect understanding of the nature of the original ecological communities of place or region. Ecology is a relatively recent science. Therefore, little information about the extent of natural ecosystems before they became degraded by human activities, and of their composition and relative abundance of species, is available. Often, small fragments of natural ecosystems continue to persist in ecologically degraded landscapes, but it is not known if they are representative of the former larger ecosystem.
For example, tall-grass prairie was once a very extensive natural ecosystem in parts of central North America. This ecosystem is now critically endangered because almost all of its original area has been converted to intensively managed agricultural ecosystems. A few small remnants of tall-grass prairie have managed to survive. However, ecologists do not know the degree to which these are typical of the original tall-grass prairie, and what fraction of the original complement of species is now missing.
Another difficulty of restoration ecology is that some natural ecosystems require a great length of time to develop their mature character. As a result, it can take decades and even centuries for some types of natural ecosystems to be restored. Therefore, it is impossible for individual ecologists, and difficult for society, to commit to the restoration of certain types of endangered ecosystems. For example, some types of old-growth forests do not reach their dynamic equilibrium of species composition, biomass, and functional character until at least 300–500 years have passed since the most recent, stand-replacing disturbance. Clearly, any initiative to reconstruct these kinds of old-growth forests on degraded land must be prepared to design with these conditions in mind, and to follow through over the longer term.
Another dilemma facing restoration ecologists is their incomplete understanding of the ecology of the species they are working with, of the relationships among those species, and of the influence of non-living environmental factors.
A problem that must be dealt with in many situations is the fact that environmental conditions may have changed significantly, perhaps permanently. Under an altered environmental regime, it may not be feasible to restore original ecosystem types. Ecologists must then propose alternative restoration plans that compliment or approximate the their original intent.
These various problems of restoration ecology are important, and the difficulties they engender should not be underestimated. However, enormous benefits can potentially be attained by successful restoration of the populations of endangered species or of threatened ecological communities.
Programs of restoration ecology require an integrated application of ecological knowledge. Most activities in applied ecology focus on the exploitation and management of species and ecosystems for the direct benefit for humans, as occurs in agriculture, forestry, and fisheries management. In restoration ecology, however, the exercise in applied ecology is undertaken to achieve some natural benefit in terms of the preservation or conservation of biodiversity and environmental quality.
Restoration ecology is a severe test of our knowledge of ecological principles and of environmental influences on species and their communities. To successfully convert degraded environments and ecosystems into self-maintaining populations takes an extraordinarily deep understanding of the complex principles of ecology.
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