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قراءة كتاب Comparative Ecology of Pinyon Mice and Deer Mice in Mesa Verde National Park, Colorado
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Comparative Ecology of Pinyon Mice and Deer Mice in Mesa Verde National Park, Colorado
Eriogonum umbellatum
Polygonum sawatchense
Delphinium nelsonii
Penstemon linarioides
Fresh diggings of pocket gophers were observed along the trap lines. Badger tunnels were noted in numerous surface mounds that are remnants of prehistoric Indian dwellings, but no badgers were seen. Numerous deer and several rabbits were present. Juncos, two species of jays, and woodpeckers were seen daily. No reptiles were observed.
Both Peromyscus maniculatus and P. truei were caught in this area (Table 1).
A circular trapline, 1,000 feet in circumference, was established on November 16, 1961, in a stand of big sagebrush, and was operated for 30 consecutive nights.
The vegetation of the trapping area was predominantly Artemisia tridentata (big sagebrush), interspersed with a few scattered seedlings of pinyon and juniper. This stand was burned in 1858 (tree-ring date by David Smith) and some charred juniper snags still stood. The deep sandy soil also supported a variety of grasses and a few other small plants. The following species were common in this area:
Bromus inermis Oryzopsis hymenoides Poa fendleriana Sitanion hystrix Solidago petradoria Orthocarpus purpureo-albus |
The 15 to 20 acres of sagebrush were surrounded by pinyon-juniper forest. The trapping station closest to the forest was approximately 100 feet from the edge of the woodland. More P. truei than P. maniculatus were caught here (Table 1).
The trapping area lies north of Cliff Palace, eastward of the loop road, at elevations of 6,875 to 6,925 feet. Two pairs of traplines were run from January 9, 1962, to January 12, 1962, and from February 13 to 15, 1962.
Vegetation was pinyon-juniper woodland with an understory of mixed shrubs. One to four inches of old snow covered the ground during most of the trapping period, but the ground beneath trees and shrubs was generally clear, providing suitable location for traps.
Numerous juncos and jays were seen in this area; deer and rabbits also were present.
Individuals of P. truei and of P. maniculatus were taken (Table 1).
Navajo Hill is the highest point (8,140 feet) on Chapin Mesa. The top of the hill is rounded and the sides slope gently southward and westward until they level out into mesa-top terrain at elevations of 7,950 to 8,000 feet. The northern and eastern slopes of the hill drop abruptly into the respective canyon slopes of the East Fork of Navajo Canyon and the West Fork of Little Soda Canyon. The gradually tapering southwestern slope of the hill extends southward for one mile and is bisected by the main highway, which runs the length of the mesa top.
Heavy growths of grasses cover the ground; Amelanchier utahensis, Cercocarpos montanus, and Fendlera rupicola comprise the only tall vegetation. Trees are lacking on this part of the mesa, except on the canyon slopes, where Quercus gambelii forms an almost impenetrable barrier.
Four traplines were run from May 4-7, 1962, and from May 9-12, 1962. P. maniculatus was taken but P. truei was not present here in 1962, or in 1964 or 1965 when additional trapping was performed as a check on populations (Table 1).
Other species trapped include the montane vole, long-tailed vole, and Colorado chipmunk. Mule deer and coyotes were abundant in the area. Striped whipsnakes, rattlesnakes and gopher snakes are known to occur in this vicinity (Douglas, 1966).
In 1934 a widespread fire deforested large areas of pinyon-juniper woodland on the northern end of Wetherill Mesa. The current vegetation consists of shrubs with a dense ground cover of grasses. Many dead trees still remain on the ground, providing additional cover for wildlife.
The trapping area was a wide, grassy meadow, three and a half miles south of the northern end of the mesa. A pronounced drainage runs through this area and empties into Rock Canyon. Four traplines were run parallel to each other. The first lines were established on May 23, 1962, and the second pair on June 3, 1962.
Another pair of lines was run in a grassy area two miles south of the northern escarpment of Wetherill Mesa. This area was one and a half miles north of the above-mentioned area. These lines ran along the eastern side of a drainage leading into Long Canyon. The vegetation was essentially the same in both areas, and they will be considered together.
The vegetation was composed predominantly of grasses. Quercus gambelii and Amelanchier utahensis were the codominant shrubs. Artemisia tridentata and Chrysothamnus depressus (dwarf rabbitbrush), were common. Plants in the two areas included the following:
Individuals of P. maniculatus and of Reithrodontomys megalotis were caught (Table 1).
Table 1—Major Trapping Localities in Mesa Verde National Park, Colorado. Vegetational Key as Follows: 1) Pinyon-Juniper-Muttongrass 2) Pinyon-Juniper-Mixed Shrubs 3) Juniper-Pinyon-Bitterbrush 4) Juniper-Pinyon-Mountain Mahogany 5) Grassland with Mixed Shrubs 6) Big Sagebrush 7) Pinyon-Juniper-Big Sagebrush 8) Grassland.
Locality | Date | No. trap nights | P. truei | P. man. | Type of vegetation |
Morfield Ridge | Sept. 1961 | 1080 | 0 | 83 | 5 |
Oct. 1963 |