Ecosystem Conservation

Each organic being is striving to increase in a geometrical ratio . . . each at some period of its life, during some season of the year, during each generation. .. .

—Charles Robert Darwin (1859), On the Origin of Species harvesting history

All species, as Darwin noted, are striving to survive and multiply in a ''geometric ratio'' (Fig. 9.5). Homo sapiens is no different from any other species, particularly in view of our geometric population growth during the past several centuries (Fig. II). Like other species—for fortune or survival—we also exploit the largest and most accessible resources first before moving on to smaller, less abundant resources. The history of resource exploitation by humans in Antarctica has been no exception.

Since Terra Australis Incognita was first imagined, resources have been the allure of Antarctica (Plate 2). Suggestions about Antarctica as a ''tropical paradise'' with masting timbers or grain crops had propelled nations southward (Chapter 3: Terra Australis Incognita). However, it was only after Cook's voyage south of the Antarctic Circle in the late 18th century that humans began capitalizing on the rich resources that actually existed in the region.

What determines the order in which species are harvested from ecosystems?

Around Antarctica, humans began with the seal and penguin species that could easily be collected on patches of land around the continent. After diminishing their populations, technologies were developed to effectively capture other marine living resources. The largest and most accessible animals—the whales—wereex-ploited next. Following the progressive decline of the great whale species, fish and invertebrates now are the targets in the Antarctic marine ecosystem. This history of harvesting species in the Antarctic marine ecosystem can be used to illustrate the impacts of uncontrolled exploitation, the resilience of natural systems, and the challenges of sustaining our living resources for future generations.

Upon his return to England in 1775, Captain James Cook noted that there were extensive populations of the Antarctic fur seal (Arctocephalus gazella) on beaches throughout the subantarctic islands. These large marine animals represented an obvious and easily accessible source of capital, and by the end of the 18th century fur sealing had become a major commercial enterprise in the Southern Ocean (Fig. 10.1).

Fur sealing climaxed at South Georgia around 1800—within a mere 25 years of Cook's initial observation. By 1822, an estimated 1,200,000 seals already had been harvested, nearly wiping out the South Georgia population (Fig. 10.1). The sealers then moved to South Shetland Islands north of the Antarctic Peninsula, where there were additional abundant fur seal colonies, and within 3 years more than 320,000 fur seals had been harvested. The sealers than expanded their efforts to the South Orkney, South Sandwich, and other subantarctic islands. Again, populations of these seals were decimated, only more quickly because of the sealers' prior experience and improved technologies. When the sealers returned to these islands at the end of the century, after more than 50 years, the fur seal populations had not recovered (Fig. 10.1).

Elephant seals (Mirounga leonina) also were harvested during the 19th century, but not as relentlessly as the fur seal. Recognizing the consequences of un-

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