2010-12-17_REVISION - C1981019 (160)

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2.0 SAMPLING METHODS 2.1 Community Type Mapping Preliminary community mapping of the study area (prior to sampling) was completed using 2002 true-color aerial imagery with approximately 1.5-meter resolution, Communities were generally delineated based on photographic signatures to a polygon size of approximately one acre using ArcGIS software, and without benefit of ground reconnaissance. Ground-truthing, correction, and refining of these preliminary delineations was completed during the summer vegetation surveys and all corrections were noted on field maps. Following ground-truthing activities, the vegetation study area, as well as a two-mile wildlife study boundary external to the vegetation study area, was re-delineated to a polygon size of approximately 0.25 acre, taking into account field corrections. The precision of this post-sampling delineation was substantially aided given the acquisition of 0.5-meter resolution color-infrared remote sensing imagery exposed in September of 2005 (see Map V1). Mapping and ground-truthing identified six major 40 communities (Aspen, Bottomland, Grassland, Juniper Scrub, Mountain Shrub and Sagebrush) and numerous minor communities (e.g. cultivated fields, wetlands, etc.), as well as several sub-types (e.g. mesic, xeric) of various communities. 2.2 Sample Layout The sample layout protocol for 2005 baseline vegetation evaluations is a procedure designed to better account for the heterogeneous expression of vegetation communities within the study area while precluding bias in the sample site selection process. By design, the procedure is initiated randomly, and thereafter, samples are located in a systematic manner, along grid coordinates spaced at fixed distances, e.g. 100 ft. (see the lower left corner of Figure V-1 and Map V1). In this manner, "representation" from across each community type is "forced" rather than risking the chance that significant pockets are entirely missed, or overemphasized as often occurs with simple random sampling. The procedure for sample location within the vegetation study area occurred as follows. First, a systematic grid that could be "nested" (e.g. 100 ft. x 100 ft.) was selected. By nesting, it is meant that grid dimensions could be readily changed to 100 x 100, 200 x 200, 300 x 300 or so on so that it was possible to provide approximately 50 coordinate intersections that could be used for sample sites within each community type (or 15 to 30 for reference areas). For example, one type that only occupied minor CIEEDAR CREEK A5530A'II9Effi, INC. Page 5 2005 Collom Vegetation Survey