400-1 



300- 



2 

 t- 



O 

 O 



200 



en 



< 

 S 

 o 



100- 



A Toll Coulee Shrub 



• — Silver Sagebrush 



B — Scirpus Morsh 



A Grassland 



O Coulee Trunk 



O— Scorio 



1977 



1978 1979 



l| Foil tropping only 



1 

 980 



Figure 21. Year-to-year changes in small mammal biomass for six habitats 



sampled in the Circle West study area (control and experimental 

 data are averaged for combined spring-fall data for each 

 habitat) . 



400- 



300- 



o 

 o 



o 200- 



< 

 2 

 O 



o 



100- 



z 

 •1 

 I 



0- 



-100- 



Toll Coulee Shrub 



Silver Sagebrush 



Scirpus Marsh 



1978 



— I 1 



1979 1980 



A Grosslond 



O— — Coulee Trunk 

 D— Scoria 



Figure 22. Year-to-year changes in spring-fall small mammal biomass change 

 for six habitats sampled in the Circle West studv area (control 

 and experimental data are averaged for each habitat). 



-50- 



