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Fauna Series No. 1
Methods
Fauna of the National Parks
of the United States
PROBLEMS OF GEOGRAPHICAL ORIGIN
DILUTION OF NATIVE STOCKS BY
HYBRIDIZING (8)
The distribution of vertebrate life and correlation of speciation with geographic range is one of the most fascinating of zoological studies. The ranges of some forms were not even worked out before those animals were exterminated. This is true of the grizzlies. So many of the grizzlies are extinct that the taxonomy of the species will never be fully known.
But this is only part of the story. There is a great and growing tendency to transplant animals from one part of the country to the other without any regard to the native range of each form. This means hybridization of one subspecies with another and a gradual muddling until many forms are lost.
In the national parks it is especially desirable to preserve the pure native strains. This can not be done if related subspecies of the park animals are introduced in adjacent territories, and consequently the only solution for problems of this type is to seek for a reform in restocking practices. The only way to secure protection would be to designate a Federal commission or agency through which all stocks for transplanting purposes would have to be cleared.
Elk transplants from Yellowstone. – This needed reform in restocking practice might well start with the National Park Service itself. The elk of Yellowstone (Cervus canadensis canadensis) have been planted widely within the range of the other species and subspecies of this animal. There are Yellowstone elk in Rocky Mountain, Mount Rainier, Crater Lake, and the Guadalupe Mountains by Carlsbad. At the time the Yellowstone elk came to Rocky Mountain there were probably still native elk in the park. While it is true that they were supposedly of the same species, nevertheless any possibility of studying intergradations or races which might have existed is now lost. The Yellowstone elk in Mount Rainier have drifted in from the Cascades east of the park.15 Probably the original elk of Mount Rainier were the Roosevelt elk, and therefore any reintroduction should have been of this species. If there were ever elk in the Guadalupe Mountains, they were probably the Merriam elk, a southwestern species now extinct. In any event, there would be little value in having Yellowstone elk down in the Guadalupes. There are many who believe that the educational value of seeing an animal lies in the significance of that animal's relation to its environment and past history. When the species are mixed or replaced, there is nothing left but just another elk.
The purpose of this discussion is to bring up the question of Park Service policy on shipping breeding stock to alien localities. It so happens that none of the elk plants discussed above was made in the parks where the elk now exist. But they were distributed in response to outside requests. Because of their proximity, they drifted into the parks, and the results were the same.
The situation seems to indicate that the Park Service, in order to protect its different faunas, would be justified in establishing the policy of shipping animals only to points within their native range (museums and zoological gardens, of course, excepted).
Caribou and reindeer in Mount McKinley. – This is a striking illustration of the danger that an outstanding native park animal may be lost through hybridization with an exotic variety introduced in the surrounding region.
Ten reindeer from eastern Siberia were introduced into Alaska in 1891. By 1902, 1,280 reindeer had been imported. To-day these animals number about 200,000 in Alaska. Being very closely related to the caribou, they hybridize readily; so that the future status of the caribou is questionable. The reindeer industry has spread eastward across Alaska until reindeer are now at Broad Pass, just outside of Mount McKinley National Park. The caribou of Mount McKinley are one of its great values. While the Mount McKinley caribou are separate from the main caribou migration in the north and east, they are nevertheless a considerable band, of about 50,000, with a local seasonal migration, and they are so situated as to be on the reindeer frontier unless some measure is taken to keep reindeer away from the Mount McKinley area. In 1926 Dixon and Wright saw reindeer, caribou, and hybrids in the park. Now, with the stated aim of the industry to hybridize caribou and reindeer and the natural tendency for this hybridization to occur anyway, it becomes increasingly valuable to maintain the Mount McKinley caribou as a pure strain. The Park Service, the Biological Survey, and many others recognize this situation and are trying to prevent its unfortunate consequences. Whether anything can be done to save the Mount McKinley caribou, ultimately, is a question.
Aside from hybridization or driving out native forms, the great danger in all such introduction of exotics lies in the possibility of bringing in some pest on disease which would prove fatal to the native species. No reindeer plagues have occurred in Alaska yet, but we do not know the potentialities.
15 Mammals and Birds of Mount Rainier National Park, by Taylor, Walter P., and Shaw, William T. National Park Service, Department of the Interior, 1927, p. 116.
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EXPOSURE OF NATIVE SPECIES TO
DISEASES AND INFLUENCES OF ALIEN FAUNAS (9)
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Last Modified: Tues,
Feb 1 2000 07:08:48 pm PDT
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