DALLES POCKET GOPHER 3 



plants to die. Close inspection of an infested range may reveal gullies 

 where gopher runways have been caved in by livestock, as well as sheet 

 erosion where roots of grass clumps are exposed. 



On the other hand, pocket gophers are of positive as well as negative 

 value. Gopher activity results in better aerated, looser, and more thor- 

 oughly tilled soils. The earthworm has been noted for simJar activities 

 in soil formation. Darwin (3) found that earthworms may bring up 

 enough soil to cover the ground 1 inch thick in 5 years. Somewhat 

 parallel is the observation by Seton (7) that in some places pocket 

 gophers completely plow the surface of the land, turning it all over at 

 least once in 2 years. The desirability of such active soil disturbance may 

 be questioned. Soil displaced by pocket gophers on subalpine range in 1 

 year, according to Ellison (4), covered 3.5 percent of the ground surface. 



Pocket gopher control on western mountain meadow ranges began as 

 an experiment on the Ochoco National Forest in 1914, when the 

 gophers were reported to be destroying grass sod on meadow r s. The fol- 

 lowing year control work on western ranges was organized on a project 

 basis and continued until World War II. Results of gopher control on 

 the Ochoco and in other sections of the West have not been clearly 

 determined, and the need for control has often been questioned. 



METHODS OF STUDY 



To develop a basis for judging the need for pocket gopher control 

 and the results to be expected from it, a cooperative study was made by 

 the Fish and Wildlife Service and the Forest Service from 1931 through 

 1948. The life history of the Dalles pocket gopher was studied, as well as 

 the effect of gophers on the composition, density, and value of moun- 

 tain meadow vegetation. 



The life history study consisted of (1) the excavation or partial exca- 

 vation over the 17-year period of about 200 burrow systems to observe 

 burrow construction, food storage, and nesting habits; (2) examination 

 of 97 specimens for weight and size, and of 154 specimens for sex ratio; 

 and (3) feeding trials with 5 pocket gophers to determine the amount of 

 plant material they would consume and their relative preference for 9 

 common native plant species. 



The study of the effect of the Dalles pocket gopher on vegetation was 

 conducted on two adjacent mountain meadows, separated by a running 

 stream, on the Ochoco National Forest in the Blue Mountains of eastern 

 Oregon (fig. 2). The meadows were typical of depleted mountain 

 meadows in eastern Oregon, and both appeared to have a heavy pocket 

 gopher population. The meadows were in poor range condition, because 

 sheep from a nearby stock driveway had grazed them heavily for many 

 years. The driveway was moved in 1931, and from then until the end of 

 the study the meadows were grazed by sheep as part of a regular national 

 forest allotment. About 30 deer used the meadows during the first years 

 of the study, but their numbers were greatly reduced toward the end. 



To study the effect of the presence or absence of pocket gophers on 

 range vegetation, four similar quarter-acre plots were marked out, two 

 on meadow A and two on meadow B. One plot in each pair was fenced 

 against sheep and deer; the other was left open to grazing. The four 

 plots were treated as follows: 



