INTRODUCTION 



The Circle West vegetation monitoring program was begun in 1978 at the 

 request of Dreyer Brothers, Inc., to provide long-term monitoring of the 

 productivity of certain vegetation types in McCone County, Montana. This 

 study is essentially a continuation of the Circle West Baseline Vegetation 

 Study, the rationale and results of which have previously been published 



(Prodgers 197S) 



Aerial Production 



METHODS 



Twelve permanently fenced exclosures (figure 1) were sampled during 

 this study. (NOTE: exclosure No. 9, Juho/Ansc-Agsp, is shown in figure 1 

 but was not sampled in 1978). The 1978 productivity sampling procedures 

 were the same as those used in 1977. Sampling took place from August 14, 

 1978 through August 26, 1978. The number of productivity samples taken 

 per exclosure was determined using 1977 data. 



Frequency and Coverage 



In each exclosure, twenty 20 cm x 50 cm plots were sampled for coverage 

 using the technique described by Daubenmire (1959). Coverage was estimated 

 as accurately as possible; cover classes were not used. Plots were located 

 along contours in series of ten. None of these plots have been clipped. 

 Color transparencies were taken of eacn plot at the time of sampling. 



RESULTS 



Aerial Production 



Increased precipitation and greatly reduced grasshopper densities 

 combined to result in much higher productivity values in 1978 than in 1977. 

 In 1978, Hay-June precipitation at Circle, Montana, was 23.9 cm (9.4 in) 

 and April-July precipitation was 32.8 cm (12.9 in). Grasshoppers, when 

 present at the productivity exclosures, were observed in small numbers. 

 Changes in productivity betv/een 1977 and 1978, expressed in kilograms per 

 hectare, are summarized in table 1. 



