400 



300 



A Toll Coulee Shrub 



• Silver Sagebrush 



•— Scirpus Marsh 



A* •• •• Grosslond 



O Coulee Trunk 



O- Scorio 



o 

 o 



— 200- 



< 

 S 

 o 



100- 



1977 



1978 1979 



_|J Fall tropping only 



1981 



Figure 13. Year-to-year changes in small inaminal 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). 



400-1 



300- 



o 

 o 



t. 200- 



4 



z 

 o 

 m 



100- 



X 



u 



0- 



-100 



A Toll Coulee Shrub 



#— — — Silver Sogebrush 

 W—-— Scirpus Marsh 



^"^ -A 



A' Grosslond 



O Coulee Trunk 



D— Scoria 



1978 



— I 



1979 



1980 



1981 



Figure 14. Year-to-year changes in spring-fall small mammal biomass 

 change for six habitats sampled in the Circle West study 

 area (control and experimental data are averaged for 

 each habitat). 



-47- 



