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Chapter 1 Strangers and Natives 1 KNOWING NATURE THROUGH NATIONALITY “The United States is having a problem with aliens,” announced the National Safety Council’s Environmental Health Center as the twentieth century drew to a close. “Not illegal immigrants or space invaders,” elaborated the Center—a division of a parent organization more commonly associated with efforts to enforce seat belt laws, combat drunk driving, and promote the careful use of Wre extinguishers—”but plants and animals that reach the shores and stay.” A California journalist had adopted the same approach the previous year, opening his article about immigrants with the remark that “the strangers come from far and wide.” “Then they make themselves so much at home, helping themselves to food and water while producing offspring,” he went on to explain, with the result that “the original occupants are forced to move.” Then, once more, comes the unexpected twist: “These strangers are plants, not people.”1 A host of similar pronouncements that play on words and subvert familiar notions indicate that discussions of undesirable immigrants in the United States are now just as likely to include flora and fauna as they are to involve the more conventional human variety. Organisms from elsewhere cause concern because they can be invasive species—which President Clinton’s executive order of 1999 on the subject deWned as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.”2 Invasive aliens have affected individual native species through competition, predation, hybridization, and disease.3 Arriving in ever-increasing numbers, they may also initiate fundamental transformations in ecosystems, changing them almost beyond recognition.4 Thirty years ago, a biologist claimed that an international medley of overseas species had left Florida “biologically traumatized.” Thanks to this UC_Coates.qxd 9/25/2006 2:57 PM Page 1 multinational assault, a “south Floridian could conceivably watch a walking Siamese catWsh crawl out of a canal choked with the Asian weed hydrilla, while Columbian iguanas scampered through Australian pines beneath a squadron of Amazonian parakeets.”5 In the trans-Mississippi West, Wre-adapted cheatgrass from Eurasia encroaches on scrublands hitherto dominated by sagebrush. As a result, Wre incidence has increased from once every 60–110 years to once every 3–5 years—a punishing rate that native flora cannot withstand. Expanding standard conceptions of natural disaster, Interior Secretary Babbitt announced in 1998 that the “invasion of noxious weeds has created a level of destruction to America’s environment and economy that is matched only by the damage caused by floods, earthquakes, wildWre, hurricanes and mudslides .”6 In fact, many scientists increasingly believe that invasive “biological immigrants” are second only to habitat loss as the major cause of the depletion , endangerment, and extinction of indigenous species.7 Even George W. Bush is doing his bit to rein them in. One of the president’s favorite activities at his 1,600-acre ranch in Crawford, Texas, is clearing the “plague” of tamarisk, a tree from North Africa (also known as salt cedar) that desiccates the soil and elbows out native trees; meanwhile, the First Lady is planting buffalo grass—part of a wider plan to restore the ranch to its native splendor . And, as part of efforts to promote his environmentalist credentials during a pre-election trip to Florida in April 2004, the president took up an enormous pair of pruning shears and hacked away at earleaf acacia, a fastgrowing evergreen from Australia that displaces native vegetation. Introduced as an urban shade tree in the early 1900s, the acacia is widely dispersed via its seeds by a variety of birds (prominent among them another foreign species, the European starling). In some instances, nonnative plants and animals have become the primary threat to native biodiversity.8 The National Park Service ranks these “habitat snatchers” ahead of air pollution, off-road vehicles, excessive visitor pressure, and oil drilling on adjacent lands as threats to the integrity of certain parklands. After more conventional pressures on them are relieved, native species can rebound. The recovery of heavily denuded eastern deciduous forests since 1900 is one of the great success stories of spontaneous ecological restoration. Yet some ecologists would argue that the impact of a European insect such as the balsam woolly adelgid (which probably arrived with imported conifers) is far less reversible than agents of change such as logging or even acid rain. These tiny, sap-sucking, aphid-like insects are killing off massive quantities of old...

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