We have been privileged, in the last several weeks, to witness wildlife and riparian restoration projects that include bison, Aplomado falcons, Bolson tortoises. and prairie dogs; we have seen streambeds saved from extreme erosion. We have also discussed more radical plans to reintroduce species, like the cheetah, that were made extinct in North America just after the last ice age, through the “restoration” of proxy species from other continents, with the view to recreate, as much as possible, the environment that predated human settlement.
These investigations led to debates about what restoration means; how to choose a point in history as the goal of restoration; if it is just to extirpate “alien” or “invasive” species; and what principles should inform the answers to these questions.
Though many of us concluded that a true or complete restoration is not possible–that successful efforts include our desires for the future in a mosaic with the available past–it is clear that this work of repair is crucial to the preservation of biodiversity and functional wildland corridors across international borders. That immigrants use such corridors to avoid official border checkpoints makes restoration in the borderlands a more political issue than it might seem at first.
Even a glance at the history of the term “alien” shows that the same kind of pejorative language is used for unwanted peoples as well as unwanted species. Immigrants who have been invited into the borderlands can quickly become “vermin” or “weeds” once their original purpose has been served. Many of us decided that we did not want to continue to refer to species as “alien” in light of this history of political violence against “alien” ethnic groups. At the level of ecology, however, I think it is necessary to assess the effects of an introduced species on its host ecosystem when judging the effects of our own actions on the larger world. We considered the effects of tamarisk on desert riparian ecosystems, and I concluded that the tamarisk, which dries up the soil around it through its high water demand, should, if possible, be controlled in the name of a functioning river environment. This application of a Leopoldian principle–the good of the biotic community as the center of “good” itself–suggests that introduced species should not be allowed to destroy ecosystems, but need not be exterminated. The false choice of inaction versus purification suggests that environmentalists should be careful not to import the language of eugenics into theories of restoration.
Immigrants are not alien invaders bent on destroying our home; humans are all one species. That’s my thought here at the 4th of July.