METHODS 

 Aerial Production 



Twelve permanently-fenced exclosures (figure 1) were sampled during the 1980 

 study. (Note: exclosure No. 9, Juho/Ansc-Agsp, is shown on figure 1 but was 

 not sampled in 1980.) In 1980, productivity sampling procedures were the same 

 as those used in 1977, 1978, and 1979. The number of samples taken per 

 exclosure was determined from previous data. Sampling took place from August 15 

 through August 25, 1980. 



After clipping, four exclosures were opened for grazing to reduce litter 

 accumulation from previous years. These exclosures contained the following 

 communities: Dist-Agsm, Arca/Agsra/Bogr , Stco/Bogr-Caf i , and Bogr-Caf i/Stco. 

 Because of excessive litter buildup, grazing of other exclosures was desired, 

 but livestock were not present in many pastures containing exclosures. 

 Livestock use of exclosures was monitored frequently; nevertheless, this use 

 ranged from very light (Bogr-Caf i/Stco) to heavy (Stco/Bogr-Cafi) . All 

 exclosures were closed to grazing by autumn 1980. 



Frequency and Canopy-Coverage 



Within each exclosure, twenty permanently-located 20 cm x 50 cm plots were sampled 

 for frequency and plant canopy-coverage using a modification of the technique 

 described by Daubenmire (1959). Unlike Daubenmire's technique, cover classes 

 were not used, but plant canopy-coverage for each species was estimated as 

 accurately as possible. The same series of plots were sampled in 1980 as in 

 previous years. These plots have never been clipped. Color transparencies of 

 each plot were taken at the time of sampling. 



Species Density 



Canopy-coverage data were used to determine species number for each 

 community type. In each exclosure, the average number of species per plot 

 (species density) and the number of species per set of 20 plots were calculated 

 using the 1977-1980 data. 



-3- 



