DAMAGE TO RANGE GRASSES BY THE ZUNI PRAIRIE DOG 



11 



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. 



Kind of grass. 



Total- 

 protection 

 area. 



Rodent- 

 grazed 

 area. 



Cattle and 



rodent 

 grazed area. 



Quantity 



destroyed 



by rodents. 1 





Grams. 

 43.7 



Grams. 

 7.3 



Grams. 

 2.6 



Grams. 

 36.4 







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. 



O ^OO /.OOO 4&OQ 3.000 



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 ^5£<V2r G/?S9Af/?--- 1 



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B232I 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. 



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^k&eo/?i/c7~/ow=/oo /?£:& C£yv7~ 

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 D z.^r/^7- /=??& £/£<£: iSfoc/f 



Pig. 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 



