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