KENNETH W. ANDERSEN and J. KNOX JONES, JR.
The mammalian fauna of the western Dakotas and adjacent Montana is
relatively poorly known. Few published reports have dealt with mammals
from this part of the Northern Great Plains, and none of these involved
detailed study of a restricted area. The present report summarizes
information gathered in Harding County, northwestern South Dakota, and
includes material on the more than 50 species of mammals that are known
to occur there.
Harding County has an area of approximately 2700 square miles (Fig. 1).
The county first was organized in 1881, but the present boundaries were
not fixed until 1908. Physiographically, it lies in that part of the
Missouri Plateau frequently termed the "Cretaceous Table Lands." The
general topography is one of rolling hills and flats--mostly range land
vegetated by short grasses and sage--broken by spectacular buttes and
hills that rise 400 to 600 or more feet above the surrounding plains.
These monadnocks are "... part of a system of Tertiary erosional
remnants standing above the Late Cretaceous rocks of northwestern South
Dakota...," according to Lillegraven (1970:832), who went on to point
out: "The butte tops are flat and grass-covered. The western sides are
being actively cut away by slumping, and the topography below the
western cliff walls is hummocky with sparse vegetation. The eastern
flanks of the tables are, by contrast, less cliff-forming and less
slumped and are generally well forested with coniferous and deciduous
trees." Slim Buttes, the North and South Cave Hills, the East and West
Short Pine Hills, and the Long Pine Hills, which barely enter the county
north of Camp Crook, comprise the pine-clad buttes; other prominences,
such as Table Mountain and Sheep Buttes, are all but nude of coniferous
cover. The highest point in the county, "Harding Peak," is 4019 feet
above sea level.
Sediments underlying northwestern South Dakota include rocks assignable
to the Pierre (shale), Fox Hills (sand), and Hell Creek formations of
Cretaceous age and the Ludlow and Tongue River formations of the
Paleocene. These rocks may be exposed at the surface, but usually are
overlain by relatively thin soils that are mostly derived from them; the
best soil in the county for agricultural purposes is the loessal sandy
or silty loam in the northeastern quarter, which is derived from Tongue
River sediments (Baker, 1952).
[Illustration: FIG. 1. Map of Harding County, South Dakota, showing
location of places named in text.]
The climate of northwestern South Dakota is characteristic of the
northern part of the interior grasslands of North America--that is, the
winters are cold and the summers hot and dry. Weather data for the
period 1896-1967 at Camp Crook are representative of those gathered at
the several stations maintained in the county. At Camp Crook the mean
temperature for January is 17.3 F, whereas that for July is 71.2 F;
precipitation averages 13.17 inches annually, most falling in the months
of April through September; snowfall amounts to an average of 33.2
inches per year and is recorded from every month from September through
May (Climatogeography of the United States, no. 20-39, Camp Crook, South
Dakota, 1969).
Major surface drainage systems in Harding County include the Little
Missouri River, which flows northward through most of the western part
of the county, the South Fork of the Grand River, which originates in
the east-central part of the county and flows generally eastward, and by
the North Fork of the Moreau River, which originates in the south and
drains in a southeasterly direction. Permanent standing surface water
was virtually unknown prior to the development of artificial
impoundments.
[Illustration: FIG. 2. Central part of Slim Buttes as viewed from the
east.]
Vegetation of the grassland areas in the county is typical of that found
throughout the semi-arid Northern Great Plains. Cover on upland soils,
especially those that are clayey in substance, generally is sparse;
areas along water courses and well-watered sites elsewhere tend to have
denser stands of grasses such as bluestem (_Andropogon_). Dominant
grasses of upland are gramma, buffalo grass, wheat grass, stipa, and
tickle grass. Sage (_Artemisia_) and numerous forbs are prominent in
many areas. These grasslands are used extensively for grazing of sheep
and cattle.
[Illustration: FIG. 3. Fuller Canyon, North Cave Hills.]
[Illustration: FIG. 4. Little Missouri River southwest of Ladner. Note
beaver dam in background and nature of riparian community.]
[Illustration: FIG. 5. Stand of pines on northern part of Slim Buttes.]
[Illustration: FIG. 6. Draw with deciduous trees in North Cave Hills.]
[Illustration: FIG. 7. Spring-fed artificial impoundment in Deer Draw,
Slim Buttes.]
[Illustration: FIG. 8. Farm land in northeastern part of Harding
County.]
The wooded buttes mentioned above are at least in part within the
boundaries of Custer National Forest and support western yellow pine
(_Pinus ponderosa_) and junipers (_Juniperus_ sp.). In some ravines and
other protected sites there are groves of deciduous trees such as
cottonwood, aspen, boxelder, ash, hackberry, elm, dogwood, and hawthorn,
usually associated with shrubs such as buckbrush, chokeberry, plum,
currant, and gooseberry. These groves frequently are associated with
small springs, as the one in Deer Draw of the Slim Buttes. The major
water courses and their tributaries are essentially treeless, although
occasional stands of cottonwoods and other deciduous trees and shrubs
occur in some places--for example along the Little Missouri near Camp
Crook. Some representative habitats in Harding County are illustrated in
Figs. 2-8.
Our interest in Harding County dates from August of 1960, when one of us
(Jones) and Robert R. Patterson visited the area briefly and obtained a
small collection of mammals. Subsequently, field parties from the Museum
of Natural History collected mammals in the county in the periods 14-30
June 1961, 23 March-11 April 1963, 5-7 July 1965, and 13 May-11 June
1968. Incidental collection also occurred in the extreme western part of
the county in the period 29 June-24 July 1970 when a group was working
primarily in the Long Pine Hills of adjacent Carter County, Montana.
There are few published references to mammals in Harding County. Visher
(1914), in an early biological survey of the area, listed 40 species of
mammals, but his accounts are mainly of historic value. Subsequently,
publications by Bailey (1915), Young (1944), Goldman (1944), Over and
Churchill (1945), Jones and Genoways (1967), and Henderson _et al._
(1969) have recorded mammals from the county.