[ . . . ] Invasive species are, generally speaking, those species that humans transport to a new region, where they reproduce, spread, and do ecological harm. That many species have become globetrotters is not in doubt. The issue is this: Could it be that, contrary to prevailing assumptions, invasive species are helping rather than hindering nature? Might it be the case that “invasive species will be nature’s salvation,” as Fred Pearce opines in The New Wild (2015)?
The eradication of invasives is often preparatory to restoring ecological systems to “health,” defined in various ways. Ecological restoration typically involves the reintroduction of native species — you can’t have a tallgrass prairie, a geographically restricted habitat, without native prairie plants. But if, as Pearce claims, the notion of restoration is predicated on an outmoded model of how ecosystems work, then is restoration doomed to fail? Might the act of returning an ecological system to some former state be an assault rather than a boon?
Pearce raises these difficult and timely questions. Invasion ecology is, relatively speaking, in its disciplinary infancy, although it has already provided scaffolding for conservation-oriented land management strategies. An ecological restorationist in your neighborhood is right now chopping down an invasive shrub, poisoning an invasive herb, or perhaps setting a trap for a non-native mammal. And by chop, poison, and trap, I mean kill; this endeavor is not for the faint of heart. Besides, it is an expensive business. The subsequent restoration of the ecological community is likewise costly and fraught with practical difficulties. Problematic invasives regenerate as often as not, or scurry back to a trapped-out system, especially those with underlying problems resulting from historically poor human management.
These challenges might encourage scientists to be cautious in dispensing advice, and encourage practitioners to wait for more complete information. But the Holocene extinction, or Sixth Mass Extinction as some call it, creates a sense of urgency. Supposedly, the rate of species loss under the influence of human disruption rivals past cataclysmic extinction events, like the one that eliminated dinosaurs at the end of the Cretaceous. This time, we humans are the comet, we are the inundating sea. Many ecologists claim that losses due to ecological damage from invasive species are among the top five factors driving contemporary extinctions. Putting this all together: the emerging science of invasion ecology is being wed to an unperfected practice of ecological restoration under the blood-red sky of a global catastrophe.
Pearce takes aim at the edifice that has coalesced around conservation efforts in the face of invasion. He does not simply remove the dodgy bricks, nor does he merely replace the edifice with a new edifice. Rather, he inverts the edifice, standing the whole darned thing on its head. Setting out to upend the conservation worldview, he writes that “when invaded by foreign species, ecosystems do not collapse. Often they prosper better than before. The success of aliens becomes a sign of nature’s dynamism, not its enfeeblement.” Elsewhere, using a medical metaphor of his own, he writes: “Alien species […] are often exactly the shot in the arm that real nature needs.” Thus, the burly nature of the New Wild — the worldview that embraces invasive species as our new saviors — is “usually richer than what went before.” This is bold and exciting. Is it correct? For the most part, I think not.
Read the whole article at the Los Angles Review of Books here.
Image Source (and another review at) The Nature of Cities here.