Proceed ca. 0.5 mile up the road to just past the cemetery. Pull 

 in on the small two-track going east just past the cemetery. 

 Site is on the hill to the south. Aspect: ca. 220 , Slope: 30 

 Elevation: 5,800 ft. 



METHODS .-- 



Field Methods 



The Quartz Hill and Thompson's Corner exclosures were 

 established and read on 11 June 1991. They were read again on 7 

 June 1993. The Dewey . Cemetery exclosure was established and read 

 on 7 June 1993. 



There is one exclosure plot and one control plot at each 

 site. Each exclosure plot is 6 ft X 6 ft, marked at the four 

 corners by metal stakes and completely covered by firm wire mesh. 

 Control plots are placed near by the exclosure and are identical 

 except they are uncovered. Each plot is divided into four equal 

 subplots (3 X 3 ft) to facilitate counting. 



In each subplot estimate the basal cover of rock, moss- 

 lichen, bare ground and vegetation, and estimate the canopy 

 cover of grass, forbs and shrubs to the nearest 5%. In each 

 subplot count the number of Arabis fecunda plants in each of 

 three size classes: 



Seedling (S) : single rosette smaller that a penny 



Rosette (R) : single rosette larger than a penny or multiple 



rosettes 

 Fruiting (F) : plants with flowers or fruits 



Data Analysis 



Changes in basal or vegetation cover between exclosure and 

 control plots can be assessed by visual examination of the 

 summary tables. 



There are no replicates of the treatments at any of the ^ 

 sites; thus, statistical tests based on parametric distributions 

 (e.g. t-test, analysis of variance) cannot be used. It is 

 necessary to use counts (frequency) and contingency table 

 analysis. The ratio of Arabis fecunda plants in year tto that 

 in year t+a in the exclosure can be compared to the ratio from 

 the control plot with a chi-square test. This test assumes that 

 the observations are independent; i.e., the plants counted in 

 year t+a cannot be the same as those counted in year t. 

 Demographic monitoring studies from low-elevation sites indicate 

 that 65% of cohorts have died after three years. Thus, the test 

 cannot be considered valid unless comparing counts taken at least 

 three years apart. Number of plants in each of the three size 

 classes can also be compared using the same test. 



