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Total plant cover in the herbaceous layer of Phase 1 of Cottonwood Ranch was <br />estimated to be 76.27 %. Sixty -five species were detected at the step - points in Phase 1 <br />(Table 3). Kentucky bluegrass (Poa pratensis) was the most abundant, covering 27.26 <br />percent of land area and comprising 20.79 percent of the plant cover. Common ragweed <br />was also abundant, covering 22.20 percent of land area and comprising 16.93 percent of <br />the plant cover. The remaining plant species each covered less than 6 percent of the land <br />area and were led by prairie cordgrass (Spartina pectinata), northern fog -fruit (Lippia <br />lanceolata), and spike rush (Carex eleocharis). <br />Comparison of the Program -level Vegetation Monitoring in Phase 1 <br />We compared the adequacy of the Program -level vegetation sampling to describe <br />the vegetation within the Phase 1 boundary. The Program -level sampling was designed <br />to describe all of Cottonwood Ranch and was also implemented in 2001 (Lack et al. <br />2002). The subset of the Program -level monitoring dataset that fell within the boundaries <br />of Phase 1 was used to recalculate the estimates of density and percent cover. There were <br />7 Program -level monitoring point- centered quarter (PCQ) points that fell in Phase 1 (1 <br />point per 12.5 acres) as compared to the 17 that were established with the Management - <br />level sampling design (1 point per 6 acres). There is one difference to note for this <br />comparison, the Program -level data collection only involved PCQ sample points in the <br />forest cover type while non - forest land cover types were encompassed within the Phase 1 <br />boundaries (forest, emergent wetland, grassland) and sampled by PCQ in the <br />management -level sampling (Figure 1). <br />Data from the Program -level vegetation sampling estimated tree density to be <br />104.31 trees per hectare in the forested areas of Phase 1, a larger estimate than the 29.13 <br />trees/ha made by the Management -level survey (Table 4). The difference is attributed to <br />the focus on forested land cover types in the Program -level sampling as compared to the <br />management -level sampling, which included non - forested land cover types, as well as <br />"edge effect" encountered in the Phase 1 sampling. Several of the Phase 1 Management - <br />level points were located at the edge of the forest where trees were less dense. Program - <br />level sampling specifically avoided edge effect by locating PCQ points a minimum of 25 <br />meters into the forest land cover type. The two surveys identified the same two most <br />abundant tree species: cottonwood and white mulberry. The Program -level survey in <br />CWR failed to detect green ash, the third most abundant species according to the Phase 1 <br />survey. All other species detected were in the same relative abundance for the two <br />surveys. <br />Sapling /shrub density was estimated to be 246.19 stems per hectare in the forested <br />areas of Phase 1 using the Program -level survey data, a larger estimate than the 79.48 <br />shrubs /saplings per hectare made by the Management -level survey (Table 5). The <br />difference may be attributed to edge effect or the presence of pockets of very dense <br />shrubs sampled by the Program -level survey. The two surveys identified the same four <br />most abundant species in the understory: rough - leaved dogwood, prairie wild rose, red <br />cedar, and white mulberry. Two species were only detected by the Program -level survey <br />in Phase 1 (hackberry and river -bank grape), while four species were only detected by the <br />Management -level Phase 1 survey (American elm, sandbar willow, false indigo, and <br />cottonwood). Although, neither method appeared to capture all species present, the six <br />