Braided Waters. Wade Graham

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СКАЧАТЬ few or no original grasslands.⁵³ Prior to humans, there had been little or no fire away from active volcanic zones, and anthropogenic fire would have quickly transformed the dry and mesic lowlands, leaving isolated pockets of dry forest remnants and vast areas of more fire-adapted species such as pili grass, favored for thatching. More recent evidence from stratigraphy on the ‘Ewa Plain of O‘ahu suggests that, even prior to Hawaiian burning, the introduced Polynesian rat may have decimated forest plant species by eating seeds and fruits unadapted to herbivores. One study argues: “The main source of destruction of the native forests was the introduced Polynesian rat, Rattus exulans, not Hawaiian agricultural clearing and burning.”⁵⁴ In his memoir, Patrich Kirch reflected: “It is a sobering thought that the delicate and vulnerable Hawaiian lowland forests may have been subject to a tidal wave of exploding rat populations, hundreds of thousands of little jaws munching away at the defenseless vegetation.”⁵⁵ Rat predation on native birds, an unusually high proportion of which were ground nesting, especially in the lowlands, was also likely devastating.⁵⁶

      Whether or not the Polynesian rat preceded them in destruction, the human colonists clearly did their part: the expansion of ‘uala culture by forest clearance was particularly widespread and devastating, as the ubiquity of “burn layers” in the archaeological record attests.⁵⁷ Evidence of the former forests on the now dry and nearly treeless West End is plentiful both in the presence of the vestigial pockets of trees that can still be seen in the deepest gulches of Mauna Loa and in Hawaiian tradition: the peak area was celebrated for a type of mythic poison trees, kalaipahoa, and for its marvelous o‘hia lehua groves, where every traveler was urged to make a lei of lehua blossoms.⁵⁸

      By 1600, at minimum 80 percent of Hawaiian lands below fifteen hundred feet were extensively altered; Kirch believes the figure to be closer to 100 percent.⁵⁹ Studies of windward O‘ahu provide an intriguing indication of former lowland forest composition: Pritchardia, or lo‘ulu palms, once apparently a dominant species, went quickly in steep decline, limited thereafter to refugia such as Nihoa and the several tiny sea stacks off Molokai that even today remain covered by palm forests. One researcher, Stephen Athens, wrote: “Pollen diagram after pollen diagram from the coastal lowlands of O‘ahu show the same thing. The native forests of the lowlands disappeared in a matter of centuries. By AD 1400 to 1500 there was essentially nothing left.”⁶⁰

      With deforestation came erosion. Erosion sequences from O‘ahu have been carefully documented: over a comparatively brief time, a number of centuries, the coastline was totally transformed with the creation of square miles of new land, as bays infilled into new valley floors, and advancing sand barriers pushing out from stream deltas created marshy flatlands behind them. For the first time in these islands, enough marsh habitat existed for several species of duck, rail, and gallinule to tarry on their great Pacific migratory routes and establish breeding populations. Some are now recognized as unique subspecies—a case of evolution responding to anthropogenic environmental change in a very brief time frame.⁶¹ Most of the currently observable alluvial fans in the state are of recent vintage, products of man-made hillslope erosion.⁶² Based on these and similar geomorpholical changes seen on O‘ahu and elsewhere from prehistory and documented on Molokai in the historic period (detailed in chapter 3), it is reasonable to assume that the same processes were at work on Molokai prior to European contact in 1778, especially on the kona shore, with its shallow reef flats stretched out below the steep, dry, easily eroded southern slopes of the ancient volcanoes.

      Polynesian expansion brought equally massive impacts to the biota. The fossil record shows wholesale extinctions of land snails and birds (these are far more easily preserved than insects and other invertebrates, about which little is known). Recent, startling discoveries in dunes at Mo‘omomi, Molokai, and in limestone sinkholes near Barber’s Point, O‘ahu, have revealed that the Hawaiians’ hunting and habitat destruction pushed at least one-half of the known land bird species, at minimum thirty-eight previously unknown birds, and between one-third and one-half of the land mollusks into extinction.⁶³

      With the depletion of easily obtainable wild foods came a greater reliance on agriculture, setting in motion a cycle of cropland expansion, agricultural intensification, and population growth, which in turn had their feedback regime in deforestation, followed by erosion, which affected nearshore reefs and bays, decreasing the productivity of the marine environment and in turn forcing an ever-greater reliance on agriculture.⁶⁴ For Hawaiians, it was a mixed bag: there was less wild food but more farmed from pondfields, terraces, and fishponds—more reliable and less vulnerable to drought, weather, and pests. A fragile environment had been transformed into a rich agricultural landscape. However, this change came at a price—one perhaps higher in social terms than in environmental losses.

      PATTERNS FROM PACIFIC ANTHROPOLOGY

      Events in Hawai‘i were part of a broad pattern across Polynesia of anthropogenic environmental change, almost always following a version of the same script: early exploitation of wild foods, leading to extinctions, especially of birds; deforestation for swidden agriculture aided by fire and introduced animals, leading to erosion and dessication; and agricultural intensification in response to slope erosion, population growth, and decreasing productivity of the nearshore marine environment. The transformation of once-forested landscapes on Pacific islands following Polynesian settlement into treeless grasslands or fernlands dominated by pyrophytic plants has been extensively documented. It was especially emphatic in New Zealand, Mangaia, Easter Island, and the Marquesas, as well as Hawai‘i.⁶⁵

      Across the Pacific, archaeologists have found evidence of colonization: charcoal and fossilized bones, shells, nuts, and pollen well preceding the first dated habitation sites.⁶⁶ This is an indication of both the odds against the preservation of early coastal sites on unstable, flood-prone sand dunes and the odds against successfully locating and excavating them. But in significant part, this is because the environmental degradation set in motion by the arrival of humans was devastatingly rapid. This fact is due to Polynesian practices, as we have seen, but also, significantly, to the structure of island biogeography that gives island biotas “their extreme vulnerability, or susceptibility, to disturbance,” in the words of botanist Raymond Fosberg.⁶⁷ In remote Polynesia—and nowhere there more so than Hawai‘i—island biogeography reaches its apogee. Just as the forests had evolved without fire, rooting pigs, or dessication, birds—whether seabirds nesting on the exposed ground by the millions or geese that had actually lost their ability to fly—had never been hunted, by humans or rats, and quickly succumbed to both. The Polynesians in their march encountered flightlessness on nearly every major island they settled; the record of extinctions in Hawai‘i is matched generally by all major Pacific island groups so far adequately studied. In New Zealand, for example, the thirteen species of moa (in Maori, as in Hawaiian, meaning chicken or chicken-like running birds) were virtually all eliminated by Polynesian settlers. A poignant detail is provided by the fact that Polynesian sailors knew that unusual concentrations of seabirds over the open ocean indicated the proximity of uninhabited islands. “It is no exaggeration,” Kirch writes, “to say that among the Remote Oceanic islands, the ‘biodiversity crisis’ began not recently but 3,500 years ago with the Lapita expansion.”⁶⁸

      These outcomes are not cases of environmental determinism in history but the complex and dynamic interaction between Polynesian social structures, economies, introduced organisms, and a series of similar yet unique island environments—outcomes predictable, to some extent, based on the variables involved yet different on every island. Patrick Kirch invoked Charles Tilly’s concept of “historically grounded huge comparisons of big structures and large processes” to “help establish what must be explained” and to shine light back on the human, contingent, and social causes.⁶⁹ Historical environmental change visible to the techniques of anthropology is one such large process, played out at the level of the island: “An ecological process with enormous consequences for island landscapes and for island cultures . . . In these large environmental ‘structures’ one seeks clues to certain big processes of political economy.”⁷⁰

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