100-1 



90 - 



80 - 



o 70 - 



(0 



=> 60- 



o 



T3 

 (0 



O 



50- 

 40 - 

 30 - 

 20 - 

 10- 

 



Rubber Rabbitbrush 

 Fragrant Sumac 



r "V*"*r I 



I 



/■*■» 



: \ 



1K r 



1960 1965 1970 1975 



Year 



1980 



1985 



Figure 3.10 



Trend in percent leaders used by spring each 

 year for two important browse species, 1959- 

 1976 and 1980-1987. Bars represent standard 

 eror of the mean. 



reliably measure what they were originally intended to 

 (especially condition), some useful information was obtained. 



One criticism of the Cole transects was that too few were 

 established for each deer population to determine whether 

 changes in use were statistically significant. Transect 

 density on our study area was at about the highest level in 

 the state. From 3 to 7 (X = 5.3) rubber rabbitbrush transects 

 and from 2 (1960 only) to 10 (X = 7.2) fragrant sumac 

 transects were measured each year. 



The relative number of transects was high for our study 

 area, but few statistical differences were observed in percent 

 leader use among years (Fig. 3.10). Because utilization was 

 measured by categories, 90% leader use was the highest 

 possible value. The upper confidence level of leader use was 

 never below 88% for rubber rabbitbrush during any of the 25 

 years of measurement. The lower confidence level was 30% 

 during 1965 and 49% during 1963, but was usually always above 

 60% leader use. Annual mean percent leader use for rubber 

 rabbitbrush was consistently high (X = 83.6+1.9 SE, range 69- 



67 



