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Wildlife Upland Reference Area - Caver. Praducuort, and Woody Stem DenstN <br />• 3.0 RESULTS <br />3.1 Vegetative Ground Cover <br />The total vegetative cover in the new Upland Wildlife Reference Area averaged 47.87 percent, with <br />litter, rock, and bare ground comprising 31.87, 2.40, and 17.86 percent respectively. Table 1 <br />presents the cover data collected during the sampling event. <br />Table 2 compares the results of the sampling conducted on the old upland wildlife reference area <br />in 1984 with the new upland wildlife reference area data. The new reference area has a total plant <br />cover value (47.87 percent) which is 89.31 percent of the total plant cover value (53.60 percent) <br />sampled on the old reference azea in 1984. A possible explanation for this contrast in plant cover <br />values is the different sampling methodology employed. The 1984 sampling event used a 10-point <br />frame for measuring cover, which allows for a greater degree of sampler interpretation than does the <br />optical-point projection device used this year. <br />Analysis ofthe relative cover exhibited by blue grama during the two sampling events also provides <br />some insight into the extremely high plant cover of 1984. Blue grama accounted for 78.2 percent <br />of the relative vegetative cover during the 1984 sampling event compazed to 40.7 percent this year. <br />While blue grama is cleazly the dominant species detected during both sampling events, it is very <br />• likely that previous years' vegetation, specifically blue grama leaves, were labeled as live hits more <br />frequently during utilization of the 10-point frame in 1984 than with the optical scope in 1999. The <br />striking difference in the frequency of litter hits between the old and new data suggests that <br />variations in the sampling methodology by the respective field technicians combined with the annual <br />timing of the sampling event (September 1984 vs. June 1999) may have tallied hits as blue grama <br />in 1984 that were counted as litter this year. Blue grama is also generally more vibrant in its growth <br />patterns later in the summer months, specifically August and September. <br />Another possible explanation for the difference in data is that 1984 was more wet than this year. <br />Upon review of Colorado climate data though, [his is not necessazily true. 1984 was a slightly drier <br />yeaz than normal in the Purgatoire River valley, with September being very dry. August of 1984 was <br />a very wet month though, and a surge in t}tt; available moisture during August, which is the peak of <br />the blue grama growing season, may have spurred the phenomena7growth by blue grama that is <br />presented in the 1984 sampling data. The spring of 1999 was very wet, and may have also <br />contributed to higher than normal plant cover values for the new upland wildlife reference area. <br />Comparison of the species diversity found on each reference area shows that the warm-season grass <br />blue grama dominates each azea. Blue grama exhibits a relative vegetative cover of 40.7 percent on <br />the new reference azea compazed with 78.2 on the, old azea. Blue grama was the only warm-season <br />grass sampled during 1984. The remaining four grasses, which aze of the cool-season life form, <br />combined represent less than three percent of the relative vegetative cover. Relative cover values <br />by forbs and shrubs on the old reference area were 8.8 percent and 9.3 percent, respectively. (The <br />. data presented in Exhibit 15, Section 5 for the old reference area incorrectly lists silver sage as a <br />forb. The data presented here counts silver sage as asub-shrub, which is consistent with the data <br />presented for the 1999 sampling event. Table 2 presents this data correctly.) The new reference area <br />contains a total of four warm-season and three cool-season grasses. The three warm-season grasses, <br />Corr Praducuon Dcmiry ~ E.h15 6]6WOVemb<r 5, 1994 `~ <br />