2014-04-22_PERMIT FILE - C1980004 (5)

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4 - 55 4.5.4 REFERENCE AREA SELECTION • Reference areas were established for each vegetation type affected by disturbance. Reference areas were selected following the completion and analysis of cover data for the affected vegetation types. This procedure permitted the integration of cover data into the reference area and selection process. Factors considered in the location and selection of representative reference sites included similarity of vegetation and habitat of the reference area compared to the affected area. Important vegetation factors evaluated were structure, composition, species dominance as expressed by cover, production, and density. Prominent abiotic habitat factors included soil type, topography, slope, and aspect. Following collection and analysis of data the comparability of reference areas and analogous affected areas was evaluated statistically for cover and production with the formula IX~-X2I~t N "~ N I 2 where X1 =Mean cover or production for the affected area • XZ =Mean cover or production for the reference area t = a t -statistic value, which vanes depending on desired level of confidence and sampling size s12 =the variance of cover or production for the affected area s22 =the variance of cover or production for the reference area nl =sample size in the affected area , n2 =sample size in the reference area When Ix, -x21 is less than or equal to the other calculated value, the affected area and reference area are considered comparable for the purpose of evaluating reclamation success. 4.4.5 REFERENCE AREA SAMPLING DESIGN All sample sites were located by a random process. The southwestern comer of each reference area served as the intersection with an x and y coordinate system. Positive coordinates were produced by a random number generator. The exact sample point was then • paced off by the field ecologist. M~ Volume 1 4-29-96