Some Post-1850 Human Influences on Pacific Coast Zoogeography

SOME POST- 1850 HUMAN INFLUENCES ON PACIFIC COAST ZOOGEOGRAPHY Charles F. Bennett, Jr. University of California at Los Angeles Although human occupance of Washington, Oregon, and California extends back in time measurable in millenia it is only within the last century that such occupance has been sufficiently influential as to produce dramatic and well documented Zoogeographie changes. When the human wave of migrants associated with the "westward course of Empire" washed upon our coastal region, the faunal complex greeting the arrivals was at once familiar and unfamiliar, useful and useless and sometimes dangerous, and, while rich in faunal diversity, the region lacked many animal species previously well known east of the Zoogeographie barriers of mountains and deserts. In common with pioneers at most places and most times within recent centuries , efforts were soon directed toward taming and altering the wilderness to suit human needs. Farmers stripped away the wild vegetation to make way for crops, miners silted up whole river systems in a frenzied search for gold, stockmen set about exterminating all competing carnivores, increased trade brought along unwanted introduction of insect pests, and man, ever critical of the environmental furniture as provided by natural events, set about rectifying the oversights of zoogeographical happenstance by deliberately introducing animals which had previously been unable to pass formidable land and water barriers. Some of the Zoogeographie changes thus promulgated can be described anthropocentrically as beneficial while others might be best described as tragic. In any event, the heavy hand of human cultural activity during the past one hundred years has importantly altered the zoogeography of the Pacific Coast of continental United States. In this article two aspects of these changes—exterminations and accidental and deliberate animal introductions—will be reviewed. Exterminations (and Serious Reductions) Of all the influences exerted by man upon the zoogeography of the earth the most dramatic is the extermination of animal forms. There is a very poignant and tragic aspect to this destructive act of man, particularly when the animal form is completely erased from the earth. The destruction marks the end of an evolutionary sequence extending back millions of years in time. Such exterminations often result when an animal is overexploited as a source of raw material, or when it is in direct competition with man, or as a result of habitat destruction by man. Perhaps the most striking extermination in the Pacific Coast region is that of grizzly bears. These large and admittedly dangerous carnivores only 100 years ago constituted a common and conspicuous element of our region's 31 fauna. Most numerous in California, the grizzly was also found in considerable numbers in Oregon and Washington.1 The presence of such a large carnivore which apparently had little regard for man—a habit probably acquired during aboriginal times when man was relatively weak and unable to defend himself against the large animal—was not to be tolerated and concerted efforts were made to completely eradicate it. So successful was the campaign that the last wild grizzlv in California was killed in 1922—in that state the bear survives as the totem animal and appears on the state flag. Grizzlies disappeared even earlier in Oregon, the last record being for 1894. Washington still has a small remnant ofa once common animal (in die north central part of the State). Grizzlies still occur in restricted areas of Idaho, Montana, and Wyoming within the continental U. S., also in parts of western Canada and they are still common in parts of Alaska. The sea otter provides an example of near extermination through uncontrolled economic exploitation. Important commercial exploitation for the excellent fur of this interesting marine mammal was begun by Russian and Aleut hunter-trappers during the mid-eighteenth century and the exploitation by one culture group or another continued to well beyond 1850. Two geographic races of the sea otter are recognized—the northern sea otter which formerly ranged through the Aleutian chain south to Vancouver, B.C. and the southern sea otter which ranged from the Straits of Juan de Fuca southward along the Pacific coast to Baja California. Although the former subspecies suffered heavily from hunters it was the latter subspecies which was very nearly...