Martin-Restoration - 178 MODELS IN COLLISION synchronicity...

Info icon This preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 178 / MODELS IN COLLISION synchronicity, indicate survival of the dwarf ground sloths for thousands of years after extinction of their continental relatives. A simple climatic explanation of ground sloth extinction will not account for the extinc- tion chronology. In an exchange between Grayson and Dave Meltzer (2002, 2003) and Stuart Fiedel and Gary Haynes (2003), Grayson and Meltzer decry the scarcity of archaeological deposits associated with mammoths or other creatures from the more than 30 genera of large animals that vanished close to the time of human arrival. Fiedel and Haynes, on the other hand think “there is far more support for overkill than for climate change a; the principal cause of the extinctions.” These four archaeologists do agree that the total number of unambiguous associations of human in- teractions with now-extinct mammals is represented by 14 proboscidean kill sites. I am glad to see that Grayson and Meltzer accept human im- pact as the cause of thousands of flightless bird and sea bird extinctions on oceanic islands. Only 40 years ago virtually no one, with the excep- tion of Charles Fleming, attributed moa extinction to humans. 3% TEN RESTORATION A day of darkness and of gloominess, a day of clouds and of thick darkness, as the morning spread upon the mountains: a great people and a strong; there hath not been ever the like, neither shall be any more after it, even to the years of many generations. A fire devoureth before them; and behind them a flame burneth: the land is as the Garden of Eden before them, and behind them a desolate wilderness; yea, and nothing shall escape them. Joel 2: 2—3 The give and take of public lectures has often revealed places where my interpretations needed more thought. For example, when I gave a talk at a Texas university some time ago, a skeptic in the audience surprised me with a question I have since learned to expect: “If humans killed off the mammoths, horses, and ground sloths, how did the buffalo survive?” According to Ernest Thompson Seton, early in the nineteenth century, before market hunting began, North America harbored 60 million bi— son. In the conservation community, some number between 30 and 60 million is sure to pop up whenever early bison are mentioned. How could there have been so many bison if the prehistoric First Americans and their descendants were such potent hunters? Why wasn’t the bison extinct? I pointed out that this question could be asked about whatever animal happened to be the largest of the survivors. If bison had slipped into ex- tinction, one could ask, why not the moose? And if neither bison nor moose had survived, one could inquire how elk had managed to hang on. Soon we would have to frame the question around rabbits and packrats. “Be- 179 180 / RESTORATION sides,” I went on, “of several fossil taxa of American bison, all but the smallest became extinct. And after the main extinction event, bison be— came scarce; their range shrank. At times they are hard to find in the fos— sil record. Some have claimed the animals were victims of a hot dry cli- mate in the mid-Holocene known as the Altithermal. But we know from the fossil record that bison were widely hunted. In Montana, there are jumps above thick deposits of bones of late-prehistoric bison. For what- ever reason, the genus pulled through, but at times it was a close call.” Mulling over this question later, I realized that the estimate of 60 mil- lion was something of a red herring. In the first place, it is not clear that it was ever more than an educated guess (Kay I998, 2002). Seton had extrapolated from regions where bison were historically abundant to others thought suitable for the animals, even if few or none occurred there in the nineteenth century. The seminal reporters on big game along the Missouri and Columbia Rivers, Meriwether Lewis and William Clark, could have told Seton that projecting numbers of bison across all suit- able habitat in historic times was a mistake. I have been-hooked on Lewis and Clark’s natural history ever since acquiring an edition of their journals some years ago, while attending a paleoecological meeting at the Mammoth Site in Hot Springs, South Dakota. Ransacking the journals for information about bison in the Dakotas, I spotted one riveting entry. Heading home in late August I 806, the Corps of Discovery bivouacked on the Missouri River near the mouth of the White River, in what became South Dakota. Here, near the end of their journey, Clark estimated seeing 20,000 buffalo in one afternoon, a record number in his experience. He also noted the killing of two por- cupines, an unusual event because porcupines were so highly valued for food and quills that hunting pressure eliminated them near villages. Clark noted, “I have observed that in the country between nations which are at war with each other the greatest numbers of wild animals are to be found.” The expedition was camped in a war zone (Martin and Szuter I999). Lewis and Clark also found large numbers of fearless bison, elk, and wolves in another such zone, along the uninhabited upper Missouri and the Yellowstone River in Montana. Tribes hostile to each other ranged the periphery of this area but did not settle there. Anthropologists have long recognized the existence of buffer zones, war zones, or neutral zones between warring groups (Hickerson 1970). Recently wildlife managers and ecologists have begun to consider the rel— evance of these zones in their own disciplines, modifying Hickerson’s the— ory to apply, for example, to deer living “in a ‘no—wolves’ land” between RESTORATION / 181 territories of adjoining packs (Mech I 977; Martin and Szuter I 99 9,38). Apparently such zones have had a profound influence on large-animal aggregations in the historic period (Martin and Szuter 199 9, 2002).» William Clark may have been the first to understand how bison could be so abundant in such a zone (Kay 1994; Martin and Szuter 1999). He also observed that they were fearless, another consequence of their sep— aration from humans (see Jared Diamond’s account of his experience with a tree kangaroo on an isolated mountain in New Guinea [I 997, chapter 7]). The demilitarized zone (DMZ) between North and South Korea, mined and strictly off-limits to humans, and therefore safe for huntable wildlife, represents a modern war zone. To escape hunters during mi— gration, two species of cranes seek out the DMZ as a refuge (Higuchi and others I996). . More broadly, where human populations are denser, wildlife popula- tions are usually smaller. This is another reason that European explor— ers of North America found themselves alternately in regions of scarCity and abundance. Only in uninhabited regions, such as along the Canoe River in British Columbia, did the early fur traders find abundant moose and beaver. In contrast, along the Columbia River near the Horse Heaven Hills, where salmon ran and edible wild plants were abundant, the river and its tributaries sustained large numbers of Native Americans. The Columbia was therefore a place where local populations of preferred prey such as beaver, bison, deer, elk, and pronghorn were few or absent.‘ This was not because the habitat could not support numbers of these animals but because it did support a relatively large human population, ready and willing to hunt wild game as the opportunity arose: Metapop— ulation ecology (Pulliam I 988) treats the dynamics of populations Within a large area, especially their fluctuations according to differences in habi- tat productivity or predation. With rare exceptions, early travelers, oc- cupied with survival, overlooked this dramatic interplay. . In short, bison were probably never, at least since the arrival of the First Americans, as common near settlements as they were in uninhab— ited lands. Moreover, Seton’s extrapolations appear to be based on the assumption that bison were in decline in the early I800s. In fact,.they were on the rise because Native American populations were declining due to exposure to European diseases. There is good reason to believe that human impact on the ecosystems of the North American West was ebbing when Lewis and Clark made their journey (Boyd I 9 9 9; Diamond I997; Kay and Simmons 2002; Reff I 99I ). Old World contact beginning 500 years ago reduced Native American populations by as much as 9 5 182 / RESTORATION percent; that is, only one person in 20 survived contact (Dobyns 1983, I 9 9 3). This was caused largely by the introduction of diseases such as smallpox and measles, but there was also warfare, exacerbated by the uneven availability of guns, trade goods, spirits, horses, and new reli— gions, all of which increased the intensity of intertribal warfare. Even if the depopulation were much less severe, let us say 50 percent, it would have considerably diminished human predation pressure on big game. Historic writings reflect this relaxation of Native American influence on ecosystems. In them we read of remarkably large numbers of game, including wild horses (introduced by the Spanish) and their predators and scavengers, including grizzly bears and wolves, enjoying trophic op- portunities not seen since pre—Clovis times. When reported by Lewis and Clark, three centuries after the crisis of contact, bison were thriving as they had not for thousands of years, if ever. Therefore, the question is not really “How could there have been 60 million bison in the early I8oos?” Rather, it is “How did any big game manage to survive intense hunting by early Americans?” The answer most likely varies with the animal and its behavior. Polar bears and grizzly bears, for example, are dangerous prey; the hunter all too easily becomes the hunted. Shortly before calving, caribou shed their predators on rapid, long—distance migrations north to the empty tundra of the subarctic. Bison move unpredictably across the vastness of the Great Plains, with no fixed migration route. When hunted, elk slip into dense cover, while mountain goats and mountain sheep retreat into rough country. Moose rely on a keen sense of hearing or smell to escape predators. Pronghorn race away at high speed. Deer reproduce rapidly and thrive in disturbed habitats (recently expanded to include the suburbs). Of the various conclusions one might draw from all of this, the fore- most is that we often identify as “wild” conditions those that are in fact heavily influenced by humans. In appraising ecosystems, both ecologists and the general public may overlook, or leave to the anthropologists, or simply take for granted the one mammal of overriding imp ortance -——H0m0 sapiens. Charles Kay (1998) has designated us the “ultimate keystone 9) species. (Ecologists define keystone species as organisms that profoundly influence energy flow or habitat carrying capacity.) At least until recently, many historians, conservationists, and ecolo- gists have accepted historical documents such as those by Champlain, Coronado, or Lewis and Clark as reflecting the New World when it must have been “wild,” “pristine,” and “primeval” (see, e.g., Bakeless I 961). By definition, only Europeans could significantly influence “nature,” which RESTORATION / 183 was essentially viewed as including native people. Similarly, in longing for a “last entire earth,” Thoreau and others of his time had in mind New England before the Pilgrims, when, Longfellow poetically pronounced, murmuring pines and hemlock made up the forest primeval. Hemlock qualifies but pines are suspect. Recently ecologists have come to accept the significant role of native people in changing the land and its fauna before European contact (Kay I 994, I 998; Martin and Szuter I 9 99). De— spite their value, historic records do not inform us about an America (or any other prehistorically colonized land) free of human impact. Nor do they inform us of the nature of the ecosystem when native people were at the peak of their powers, before the deadly epidemics of contact (for the Pacific Northwest, see Boyd I 9 99). The View that preliterate societies made no difference began to shift as fossils of the Neolithic became known in the Mediterranean, a land pro- foundly altered long before Homeric times. It shifted again with discov- ery of the Aztec, Mayan, and Inca civilizations in America, to name a few, along with realization of the significance of the ancient African city of Great Zimbabwe. In New Zealand, palynologists (those who study fossil and modern pollen and spores) discovered that the open, patchy forest recorded by the first English explorer, Captain James Cook, and long thought to be primeval, was not. The pollen record showed that prior to the arrival of the first settlers from Polynesia, much of New Zealand would have been a closed forest (Anderson and McGlone I 9 92). With fire, prehistoric people opened the forest. Extinction of the moas soon followed. Similarly, as discussed in chapter 6, the fossil record rarely supports the common assumption of earlier zoogeographers, including Darwin and Wallace, that whatever they found on any previously unstudied Pacific island represented “nature in the raw.” In an unwitting form of racism, zoogeographers characterized as natural the fauna—~native people included——-that they encountered on islands and archipelagos. They as- sumed that only European voyagers could overhunt native species or in- troduce lethal aliens. In fact, prehistoric settlement had radically altered the fauna of these islands (Olson and Wetmore I 976; Steadman I995; Steadman and Martin 2003 ). . It will come as no surprise that I define the “last entire earth differ- ently than did Thoreau. Prehistorians find that any given land begins to lose its wildness not when the first Europeans arrive, but when the very first humans do. In the Americas true wilderness was more than 10,000 years gone by the time Columbus reached our shores. It disappeared with the megafauna, whose calls gave voice to the forests and prairies. 184 / RESTORATION This perspective is hardly the norm. Many of us were raised on the leg- end that what Lewis and Clark saw was Wild America, America the Beau— tiful. And in truth, America is not only the beautiful but the opulent. Vastly rich in resources, endowed with highly productive soils, enjoying for the most part a temperate climate, possessed of ample waterways and ports with protected access to the oceans, blessed with many natural areas dis- playing a rich assemblage of plants and animals, and inhabited by a di- verse population of boundless energy, the Americas in general and the United States in particular are viewed with envy by many people around the world. Indeed, most Americans View their opportunities as boundless and their heritage as unique, a source of great optimism. It can come as a shock to learn that in at least one respect this her— itage is in fact woefully impoverished. A great many large animals, gifts of the evolutionary gods, were destroyed before anyone drew their im- ages on bone or stone or on the walls of American caves. The near-time extinctions deprived North America of two—thirds and South America of three-fourths of their native large mammals. It was the remaining third that so impressed Lewis and Clark. The survivors are highly valued, but they fall far short of defining the natural fauna of the hemisphere. As far as large animals are concerned, America the Beautiful is now America the Blighted. If we could travel back to near time, we would easily spot the sheer variety of unfamiliar large mammals distinguishing truly wild America. Perhaps less obvious, but no less important, would be differences in the faunal niches being filled, in the ranges occupied by various animals that still exist today, and in the impacts of all the animals on their surround- ings. These more subtle observations would also have profound effects on our definitions of “nature.” Though we cannot literally travel back in time, the comparable observations we can make based on the fossil record should open our eyes to possibilities. For example, managers may assume that the species of plants and an- imals that a habitat has been known to support in historic time are a fair representation of how things were in the ice ages. The accidental or de- liberate introduction of alien species is therefore viewed with alarm. Aren’t aliens destructive? Reality is much more complex. From fossils we know that the grasses, forbs, shrubs, and trees of the Americas coevolved with a much greater variety of large herbivores than exists today (for Califor— nia, see Edwards I992). The absence of bison in California historically may well account for the nature of California grassland as reported in early documents (Bock and Bock 2000, 38). But that does not mean the RESTORATION / 185 native grasses were never subjected to heavy grazing either by bison or by the native horses, mammoths, and other megaherbivores found in abun- dance in the Pleistocene and older fossil faunas of California and the West. The grasslands and savannas of America coevolved with many species of large herbivores and presumably with heavy herbivory. Heavy herbivory in ancient times may account for the fact that in arid regions of the southwestern United States and northern Mexico many low trees, shrubs, and sub-shrubs are armed with thorns, oils, terpenes, and/or tannins designed to repel herbivores or discourage excessive con— sumption by them. Even some of the trees in dry tropical forest com- munities are armed with thorns. Examples in Africa, southern Mexico, and Central America include the young Ceiba, whose trunks have thorns, and the spiny acacias, which have large hollow thorns colonized by ants ready to assault intruders. The spiny nopaleras studied by Dan Janzen and the deciduous tropical forests in Costa Rica and other dry parts of Central America and Mexico feature sweet fruits or pericarps that are ingested by large animals, which become unwitting agents of seed dis- persal (Barlow 2000). Ethnobotanist Gary Nabhan tells me that Native Americans may have unknowingly substituted for the large extinct quad- rupeds in dispersing devil’s claw and squash seeds. Subsequently, horses and cattle helped in seed dispersal. These rarely acknowledged changes illustrate the hazard of accepting the current extinction-pruned large mammal fauna of the Americas as the “normal” evolutionary assemblage (Janzen and Martin 1982; Bar- low zooo). The disappearance of the megafauna opened ecological op- portunities for many kinds of large animals, including (but not inher— ently limited to) those found historically. The fact that “new” animals took advantage of those opportunities makes the historic record an even more deceptive guide to any true state of nature. Big-game ecologist John Teer puts matters this way: “Some people say that success for introduc- tions of foreign animals became a foregone conclusion when the origi— nal Quaternary fauna was lost, perhaps because of overhunting by early humans” (Mungall and Sheffield I994, ix). For instance, take the question of the “natural” range of bison and the related issue of what lands are naturally suited for grazing. In the time of Lewis and Clark, native people and their horses, the latter esti- mated to number in the hundreds of thousands, occupied the Columbia Plateau in Washington. In the absence of people, I believe that the Great Basin sagebrush—grasslands would have swarmed with bison. The suc- cess of cattle in much of the West confirms that bison could have thrived 186 / RESTORATION in areas outside their historic range (Martin and Szuter I 9 9 9). The his— toric absence of bison in southwestern New Mexico and Arizona, for ex ample, may reflect the marginal carrying capacity of desert grassland and the hunting skills of Native Americans living in this region, alternately raising crops (Zea), gathering wild plants, hunting wildlife, and, when they could, hunting bison (Speth I 98 3). I...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern