The Coconino sun., 1924-11-07

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the grass on more than 5000 ,0Ot
acres of the very choice grazing lane
of the state, the areas selected and in
tested by prairie dogs being generally
the best grama grass flats and draws
In order to determine quantitativelS
the damage done by prairie dogs tC
! forage grasses under different con
i ditions, three sets of experimental
areas were established during the
year 1918 in northern Arizona Cat CO.
conino, near Grand Canyon; at Will
liams; and at Seligman) by the bu-
reau of biological survey, the Carne
gle institution of Washington and the
/ forest service. Some of the results
thus far obtained are discussed here
The prairie dog found in northern
Arizona and concerned in the expert
ments here reported Is the Zuni prai-
rie dog (Cynomys gunnisoni zuniensis
Hollister). This subspecies is of wide
distribution, being found in central
northern, and eastern Arizona, in CEN
tral and northwestern New Mexico
and in southwestern Colorado. Its
destruction of forage grasses may be
regarded as fairly typical OF the ac-
! IlNIllCO VI OOSo III
/ The procedure in the conduct of the
experiments was either to fence in the
prairie dogs on particular infested
tract, or (as at Seligman) to permit
free entry of prairie dogs while ex-
Guiding cattle; to inclose also con-
| tiguous area of similar size, so that II
could be held under total protection
from cattle as we'll as prairie dogs;
and then, by means of permanent
meter vegetation quadrats, and In
other ways, to obtain quantitative in
| formation as to the vegetation ac-
tually destroyed under grazing "a
by prairie dogs alone and (2) by cat
tie alone Tor cattle and prairie dogs
| together) in comparison with (3) the
amounts produced under total protec-
ton. This was accomplished by ac-
tually measuring the grass under to-
tai protection, under grazing by pfal-
rie dogs, and under grazing by cat
tie; by mapping the areas on the
quadrats occupied by the grasses; and
by fall clipping and weighing all vege-
tation from certain quadrats in the
areas under the different conditions.
Organization and Auspices
The project has been cooperative
from the beginning. DR.. Frederic Il.
Clements, of the Carnegie institution
of Washington, has given valuable as
sistance and advice relative to the o.
ganization and prosecution of the eX,
pertinent and has made provision fo1
the charting of the vegetation. For
mer supervisors Ira t. Yarnall ano
James A. Scott, of the Tusayan ma.
tional forest, extended many courtes.
les in connection with the work; and
| the present supervisor, George w
Kimball, has continued quarterly in
spection of the areas and assisted IN
other ways. Dr. Chas. T. Vorhies, OF
the University of Arizona, charted the
quadrats in the spring of 1919; and
lD. A. Gilchrist, biological survey ro-
dent-pest director for Arizona, as.
sisted by Ben E. Foster, supervised
the fencing Of the areas, made check
counts of the prairie dogs in the in
closures at different times, inspected
the areas at intervals, arranged for
the capture and reintroduction OF
prairie dogs, and provided for neces-
sary eradication. The writer's have
participated in the organization and
fconduct o fthe experiment from its In
ception and have inspected the areas
at least once each year, checking up on
the rodent relations, measuring the
grasses, charting the vegetation quad
rats, and clipping, weighing, and pho
tographing the grasses from the clip
quaarats.
Vegetation Affected
The region in which prairie dogs are
chiefly found is in the western part
of the great plains formation, called
by Clements (1920) the mixed prairie.
This consists of two components, a
tall grass and a short grass. Over the
greater part of the area occupied by
this formation the two occur mixed,
but toward it's eastern border the
short grasses become of minor sig
nificance, while on the western they
are of major Importance. The "tall'
grass is characterized by the presence
of wheat grass (Agropyron) and por-
cupine grass (Stipa; usually the
needle thread grass Stipa coma
ta), and the "short" grass by blue
grama (Bouteloua gracilis). There
are several additional associates OF
both compOnenIS, DuC Oniy LnoSe oc'
curing in northern Arizona are of
particular interest here.
The areas covered by this investi-
cation are in the extreme southwest
ern extension Of the great plains for
nation already mentioned. The vege
tation through most of this section is
of the short-grass type and consists OF
blue grama associated with ring grass
| (Muhlenbergia gracillima) and black
or woolly-foot grama (Boutelou eric
poda). The short-grass type is OF
greatest importance from the forage
standpoint when the blue grama is
present in quantity, and of least i'm
portance when it is associated with
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