2009-04-01_REPORT - C1994082 (6)

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a Yoast extended reference area values from data collected in 2008 • b Yoast extended reference area values from data collected in 2006 As can be seen, using allowable all-hit herbaceous cover as the basis, minimum adequate sample size was not achieved in the Sagebrush and Steep Mountain Brush types. This relates to the Log-transformed Yoast 2008 Allowable all-hit herbaceous cover (absolute) Vegetation Type Mean Cover Sample size (n) Nmin % of Affected Aread Sagebrush/Snowberry a 1.523 15 2 24.0 Mountain Brush a 1.647 15 1 48.9 Aspen Woodland a 1.939 15 1 24.4 Steep Mountain Brush a 1.249 15 4 2.7 Phase II Reclamation Area 1.673 20 1 NA The area-weighted average of these log-transformed numbers for the extended reference areas is 1.678. 90% of this value (1.510) is thus the cover standard. Inasmuch as the value for the Phase II reclamation Area is 1.673, exceeding the standard, achievement of adequate cover is indicated. • As can be seen in Figure 1, the mean allowable total "all hit" herbaceous cover observed in the 2002 reclaimed areas was lower than the standard but the confidence limit did exceed the standard. The very young (two-year old) 2004 reclamation fell short of the standard of allowable cover entirely. Experience at nearby Seneca IN has shown that very young reclamation that still has substantial cover by annual and biennial species and a large deduction for "excess " cover by those species, is likely to continue to develop the necessary predominance of perennial desirable species. Inasmuch as the 2002 reclaimed areas at the Yoast Mine were also sampled in 2004, a year that was slightly below average in moisture, it is interesting to observe the changes in cover values between 2004 and 2006, which was a year that was much below average in moisture (Figures 6b, 7b and 8b). Total vegetation cover had decreased substantially between the two years (45.6% to 38.9%). Meanwhile, cover by annual/biennial species declined from 29.0% to 11.9% and native perennial cool season grasses rose from 16.4% to 20.3%. One of the desired outcomes in the younger revegetation is for the cover by grasses to be more "restrained." In the presence of more restrained grass exuberance in the 2002 reclamation, the development of native perennial forbs has moved up from 1.7% in 2004 to 3.1 % in 2006. Development of introduced perennial forbs cover has also been somewhat restrained with alfalfa in 2006 • comprising about 0.2% cover, a level far below those that were deemed to be excessive in the 17