Sunday, July 27, 2008

Conservation Biology and Intervention

Ecological restoration is usually thought of as preserving or recreating previous conditions that were changed as a result of human activity. An important part of this is being true to both time and space. Preserving Himalayan pines in a Rochester, NY arboretum is the vegetative equivalent of a zoo; it’s not restoration. But restoring tallgrass prairie in Illinois to its presettlement condition after most of our American prairies were converted to agriculture is considered restoration.

What is not usually considered either restoration or preservation is assembling species in new configurations. This week a policy article in Science proposes, though, that such new assemblages will be required in order to preserve the existence of certain species in the face of rapid climate change. The authors call the proposed policy action “assisted colonization.” The idea is that climate may be shifting too rapidly (due to human activity) for many species to migrate on their own. In addition, human development has fragmented habitats in ways that prevent migration.

What and how should we (environmental philosophers) think of this proposal? Is it still a means of preservation? Is it preservation in a robust sense, as opposed to the sort of last-ditch, pathetic rescue that zoos attempt for the last remaining exemplars of species? What considerations should be taken into account?

While there may be some essentialist objection to the intense intervention that assisted colonization would allow, I can only see it resting on contested understandings of the natural. Migration itself is natural. For example, in the west, pinyon pine is migrating northward, and in the east, white oak is slowly migrating northward following the last ice age, 15,000 years ago. On the other hand, this particular climate change and much habitat fragmentation is human-caused. And the consequences of the current mass extinction of species are dire.

Rather, appropriate objections revolve around gaps in our knowledge. When should we act, and how much risk can we take on, especially given humanity’s past mistakes? When weighing these questions, though, we should consider that many of those mistakes happened in pursuit of other goals—political and economic advantage.

Conservation biologists and environmentalists care about preserving species, and we care about natural associations. But if climate change predictions are correct, then we can’t have it both ways. One requirement, as we proceed, is to carefully collect and analyze information, including the success and failure of restoration projects. Habitat destruction remains the greatest single threat to biodiversity, over and above climate change, and will be the first priority for decades to come. But considering these questions is wise, while we still have the luxury of thinking about them.

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