DALLES POCKET GOPHER 



29 



Table 6. — Density and composition of vegetation on grazed plot of 

 meadow A, by value 1 as forage for sheep, in specified years 1940-48- 



Year 



1940. 

 1943. 

 1945. 

 1946. 

 1947. 

 1948. 



High value 



Moderate value 



Lo\ 



7 value 



Den- 



Percent of 



Den- 



Percent of 



Den- 



Percent of 



sitys 



composition 



sity 3 



composition 



sity 3 



composition 



10.16 



39 



9.99 



38 



6.17 



23 



6.08 



29 



5.45 



26 



9.31 



45 



11.61 



43 



8.06 



30 



7.35 



27 



10.48 



39 



9.26 



34 



7.27 



27 



8.40 



35 



10.70 



45 



4.83 



20 



12.50 



42 



12.39 



42 



4.66 



16 



1 High value: Species that ordinarily would have 40 percent or more of their 

 herbage removed when meadow is properly grazed. 



Moderate value: Species that ordinarily would have 20 to 39 percent of their 

 herbage removed when meadow is properly grazed. 



Low value: Species that ordinarily would have less than 20 percent of their herbage 

 removed, or remain ungrazed, when a meadow is properly grazed. 



2 Pocket gophers were introduced into the meadow in fall of 1940. 



3 Square feet per hundred of ground cover. 



certain conclusions on their occupancy and effect on mountain meadows 

 and the need for their control. When a meadow is in poor or very poor 

 condition — low in the production of plants suitable for forage for either 

 pocket gophers or livestock — a few gophers may use such a high propor- 

 tion of the plants that the range cannot improve in grazing capacity. On 

 the other hand, when a meadow is in fair condition or better, having 

 much more palatable forage than a meadow in poor condition, the 

 plants used by a few pocket gophers would be a relatively small portion 

 of all the vegetation on the meadow. 



Because each pocket gopher has an individual burrow system that 

 takes up considerable space, and generally burrow systems of different 

 gophers do not overlap, there is a maximum population of pocket 

 gophers per acre on a meadow. Because more forage is available on a 

 meadow in fair or good condition, the foraging range of an individual 

 gopher is somewhat less than on a meadow in poorer condition. A 

 higher gopher population may result. However, the tendency of the 

 gopher to live alone and prevent intrusion on his area may limit the 

 population on such a meadow, even though forage production is suffi- 

 cient to support a much greater number. Therefore, when forage pro- 

 duction is high on a mountain meadow, gopher control may not be 

 needed as a range improvement measure unless it is desired to make the 

 forage they would use or destroy available for livestock or game. When 

 forage production is low, however, and gopher populations high, control 

 measures are definitely needed to allow the range to improve from both 

 a forage and a watershed standpoint. 



CONTROL OF POCKET GOPHERS 



Natural Checks 



There are many natural checks on pocket gophers. They are impor- 

 tant because they prevent the building up of gopher numbers to infesta- 

 tion proportions. Where natural checks are not sufficient, however, 

 artificial measures are required. 



