er 
DAMAGE TO RANGE GRASSES BY THE ZUNI PRAIRIE DOG Ey 
TABLE 3.—Quadrat study, giving weights of grasses clipped in fall from perma- 
nent meter quadrats under the different conditions as stated, to indicate the 
amount of forage destroyed by prairie dogs at Williams, Ariz., 1922. 
Total- Rodent- | Cattleand 
Quantity 
Kind of grass. protection grazed rodent destroyed 
. area. area. grazed area. by rodents.! 
| 
Grams. Grams. Grams. Grams. 
LEV EGSTECS PITT 126 0a ota Ree nee ce aE ae ERS 43. 7 7.3 2.6 36. 4 
I I 
1 Obtained by subtracting amounts under rodent-grazed conditions from those under total protection. 
The rodents concerned are chiefly prairie dogs; a negligible quantity of forage may have been taken by 
others. 
FRODYCTION OF FORCE AND QUANTITY DESTROYED BY PKIOVISE 
DOGS NO LEFT FOR LILLE STOCA: 
POUNDS FER ACRE FER YEAR 
300 4000 4500 2000 
SRO ATCN OE Loe ene ere = OE TELE O A 
RR I I = ROO PL ba 
TOTAL WHEATGRASS AND DROPSEED 
WESTERN PUHEAT GRASS 79L ONE -~~ZEEE EEE PLATS 
Eee 
SAND DROPSEED ALONE —---—----| 
Mt RING Doan ae ne ee = 
cm BB VO7TAL SLORAICGE LEODUCTION 
(o r4) BB QAS7TROYED BY PRAIRIE DOGS 
OLZEK7 4FO0R LILE STOCK 
B2321 AM 
Fig, 1.—Quantitative destruction of forage by prairie dogs. Composite record from 
experiments of four years at Coconino, Ariz., and of one year at Williams, Ariz. - 
The figures in Table 3 show that under the conditions of this ex- 
periment prairie dogs destroyed the forage at the rate of 324 pounds 
of the 390 pounds produced on an acre in the year; or, putting it 
another way, rodents reduced the available stand of the blue grama— 
the most important forage grass in the region—by 83 per cent. 
PROPOR T/ONM OF FORAGE DLE7ROYED BY PRAIRIE POCE PPNVO 
L4LAT FOR LILLE STOCK. 
PER CENT PER ACRE FL YEPIR 
2S 50 7S 400 
| TOTAL MHEAT CRASS AIND DRPOPEELED ~~ BEES O LEE LOE __| 
MWESTLERN MAHER TCRASS 77LONE—— 
SANO DFOPSLEED ALONME----————& 
PPO © 008 Sees eee. 2B PPO OOOO ooo COON = 
LOLOL GPPPLU ID eT. FERRER RRR SS %¢ 
B ACODUC TION =/00 PER CENT 
: EX OL S7TROVYED BY PRAIRIE DOGS 
O 444-7 4OR LILE STOCKH 
62321 BM 
Fic. 2.—Percentage destruction of forage by prairie dogs. Composite record from experi- 
ments of four years at Coconino, Ariz., and of one year at Williams, Ariz. 
SOME GRAZING RELATIONS. OF PRAIRIE DOGS. 
It is not the intention to imply that the rates of damage here 
shown actually prevail throughout the areas of the forage types 
here considered wherever prairie dogs are at work, for there are 
