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Fauna Series No. 1
Methods
Fauna of the National Parks
of the United States
PROBLEMS OF HISTORICAL ORIGIN
TO REESTABLISH AN EXTIRPATED
SPECIES (1)
Restoration of an animal which has been exterminated is desirable not only because it will bring back that species itself, but because it will fill once more the niche that was deserted, and so help to restore the life of the park to its primitive dynamic balance. If the extirpated species is still present in the region, reoccupation of the park by natural spread should be encouraged. This is the best answer from the standpoint of expense and likelihood of lasting success. If on the other hand, there are natural or artificial barriers in between the park and the present occupied area, restocking must be the answer. If the animal is decreasing everywhere, this step must be taken promptly.
Thus the procedure adopted for meeting the individual problem will be largely determined by the status of the animal outside the park, as is illustrated in the following examples:
Grizzly bears in Sequoia. – The grizzlies of California are extinct. The suggestion has been made a number of times that replacement be made with a Rocky Mountain grizzly. This would be such an obvious mistake that it has never been seriously considered, yet in other instances of this same kind the incongruity might be just as great though not so immediately apparent. If an animal is extinct, the situation is beyond remedy. Attempt to replace the original with a related form would merely serve to create a new problem, the introduction of an exotic with different characteristics and, more especially, different ecological requirements than its extinct relative.
Mountain sheep in Yosemite. – The Sierra Nevada mountain sheep (Ovis canadensis sierrae) disappeared from Yosemite before the close of last century. Old horns and skulls are still found about high cliffs. There is a living remnant of this bighorn in the southern Sierra near Mount Whitney, where it is reported to be slowly increasing under protection. Two other related subspecies are the Lava Beds bighorn to the north, which is probably extinct, and the Nelson bighorn, which is still extant on some nearby desert mountains to the south.
Many have already expressed a wish to see Yosemite National Park restocked with mountain sheep, there being even some indication that private support might be forthcoming for such a project. The waiting policy adopted by the Service is the only justifiable course for the present. So long as the Sierra Nevada form still exists, it is the only source which can even be considered for reintroduction purposes. A gradual return of the southern remnant is the ideal solution, and there is a fighting chance that this will take place if it continues to increase and reoccupies its range northward along the crest of the mountains. Continued heavy grazing by domestic sheep between Yosemite and Mount Whitney will be a serious obstacle here.
Even though natural reestablishment should be considered too remote a possibility, waiting would still be a necessity for practical reasons. The southern band is still small and the sheep are rarely seen. They should not be disturbed; but if they were, success in capturing the necessary number and transporting them to Yosemite would be very unlikely. It would not pay to release such costly animals as these would be near the crest of the mountains. The park unfortunately does not include the east slope, which is the habitat preferred by the sheep. They are particularly dependent on this side during the period of heavy snow, and would be without the benefit of park protection at such times.
To sum up, the conclusions in this problem are: Return of the mountain sheep to Yosemite should be planned for, because the native form is still in existence; the procedure indicated by the elements of the case is to do nothing now except to watch the Mount Whitney sheep until either they work back naturally, or, failing that, become sufficiently abundant for a restocking experiment to have a chance of Success.
FIGURE 10. – Mount Dana. The eastern slope of the
range, now outside Yosemite boundaries,
would be needed by mountain
sheep in winter.
Photograph taken July 30, 1929, at Tioga Pass,
California. Wild Life Survey No. 296
Wild turkey in Mesa Verde. – In the foregoing example the return of the mountain sheep to Yosemite is shown to be desirable, providing it can be accomplished under the proper conditions. Let us examine a second case – one in which the basic action itself is in question.
The problem is: Should the Merriam Turkey (Meleagris gallopavo merriami) of the Southwest be placed in Mesa Verde National Park ?
The Cliff Dwellers kept turkeys confined in the caves behind their dwellings. Turkey-bone implements and pieces of turkey-feather robes have been recovered, as well as many other evidences that the wild turkey was present and was an essential part of the Cliff Dwellers' economic, and possibly religious, life. There are no definite records or indications of the presence of turkeys on the mesa to-day. It would be of unusual interest and of educational value if these wonderful birds were occasionally seen, or, at least were known to be present, hidden in the forest and canyons of the mesa. In the thoughts of the visitor, these birds would be as a far cry back to that earlier life and culture, a symbol to link him more closely to that civilization as a reality. Their presence would lend a further charm and color to the wild life of the mesa to-day. But there are other considerations.
Is this the native habitat of the wild turkey ? "It is significant that by choice we find them in or near the yellow-pine type and always where living water – springs or streams – is available. Nowhere, in the memory of the oldest citizens of the State, have turkeys been resident where pine was not in evidence. If for no other reason, the adult birds seem to insistently choose pine trees in which to roost." 7 There is almost no yellow pine on the mesa, and water is very scarce.
Did turkeys ever exist here naturally, or were they brought here in a semidomesticated state by the Cliff Dwellers ? If they were brought here, from where did they come ? Probably the nearest representatives of the Merriam turkey are those found in the Chusca Mountains between Arizona and New Mexico, north of Gallup. However, they are in an extensive yellow-pine country, which is their native habitat. Since they are found so close to Mesa Verde, it would not be surprising to find that they were at one time native to the mesa, except for the scarcity of yellow pine and water.
The following note on the wild life of the Chusca Mountains region is given by Vernon Bailey: "The Navajo Indians in their religious reverence for feathered spirits have made their great reservation to some extent a bird preserve. Ducks are unmolested in the lakes and doubtless breed there in considerable numbers. Wild turkeys have held their own unusually well, but have suffered somewhat from hunting by outsiders and Christianized Indians." 8
Were turkeys left here after the Cliff Dwellers departed ? If so, what has become of them ?
If turkeys were not native to the mesa, would it not be confusing the whole significance of their part in Mesa Verde culture to place them there, and give the impression that they were native to the mesa? The significance of a visit to Mesa Verde is that it acquaints one with an earlier civilization through the actual remnants of that civilization, and it shows how that civilization was modified by, and adapted to, its particular environment. If we introduce an alien factor into the immediate setting, we are destroying the significance of the whole complex relationship between culture and environment.
These thoughts are not given to oppose the reintroduction of wild turkeys into this park. They are given simply as a preliminary analysis of the complexity of such a problem, and as an indication of some of the interactive factors which have to be considered before there can be a proper decision.
Once the desirability of reintroducing an exterminated species has been demonstrated, there are the practical problems to be worked out in the field, such as:
-
(a) Where the nearest representative of the species may be
found.
(b) Practical means of securing pairs for reintroduction.
(c) The matter of cost.
(d) Practical measures, if necessary, for temporarily protecting the new stock until it establishes itself.
7 Wild Life of New Mexico, by Ligon, J. Stokley. State Game Commission, Department of Game and Fish, Santa Fe, N. Mex., 1927, p. 113. 8 Life Zones and Crop Zones of New Mexico, by Bailey, Vernon. North American Fauna, No. 35, 1913, p. 61.
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Last Modified: Tues, Feb 1 2000 07:08:48 pm PDT
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