2008-03-27_REPORT - C1994082 (5)

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• The observed herbaceous production in the 2003 Reclaimed Area exceeded the production standard. As with cover, the young 2005 reclamation was short of the performance standard, largely because much of the production was (expectably) comprised of annuals that (beyond 10% relative production) were excluded. Annual /biennial production is expected to decline in the coming few years as has been observed many times over in older reclamation. Woody Plant Density BACKGROUND DENSITY 2007 data from the 2003 reclaimed area estimate the density of woody plants at 263 stems per acre, and thus a rise of more than 7x in woody plant density has occurred from the two-year old stage to the 4-year old stage (see ESCO 2006). Between 2005 and 2007, big sagebrush, mountain snowberry, and chokecherry proliferation as well as planting accounted for this increase. This trend suggests that the 200 stems per acre background standard should be attainable by time Phase III bond release evaluation is appropriate (another six years). In the 2005 reclamation area, the 2007-observed woody plant density level of 660 stems per acre is very encouraging for such young revegetation. ,Comprising this total are mostly big sagebrush and bitterbrush. Some of the latter may have come from nursery-stock plantings. However, most of the sagebrush and bitterbrush are thought to have developed from seeding. Species Diversity and Composition The data illustrated in Figure 5 show that the 2003 reclamation (the oldest) has predictably the smallest amount of annual/biennial plant cover of the reclamation areas sampled in 2007 at Yoast Mine (Figure 5). In 2005, when this reclamation was only two years old, there was approximately twice as much cover by annuals and biennials in this reclamation area. This pattern is repeated in the 2005 reclamation sampled in 2007 which has more than half of the cover comprised of annuals and biennials, as is typical of younger reclamation (Figure 5). The distribution of species density by lifeform (Figure 4) shows that the 2003 and 2005 reclaimed areas are more similar to the reference areas than would appear to be the case from the lifeform distribution of relative cover (Figure 5). This is important in that it shows that the basic components of the original ecosystem have indeed been returned and that it is a matter of relative proportions of species (and age or community successional status) that separates the reclaimed from the native vegetation. Perhaps the largest difference with regard to species density is in the native perennial forbs category, where native areas (as represented by the native types of Mountain Brush and Sagebrush) tend to have twice as many species of native perennial 13