2010-02-01_REPORT - M1983194 (2)

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Above ground biomass production for native grasses, forbs and shrubs declined in 2009 (Table 6-4). The 6.8 percent decline in total production in 2009 is most likely the result of less precipitation in the later half of the growing season. Native grass production has been consistent since 2007. Native forbs production declined in 2009 but remains substantially higher than values measured 2004 through 2007. Production of native shrubs declined 15.6 percent in 2009 from 2008 but remains consistent with 2007 production. Substantial increases in annual grass and weedy forbs occurred in 2009; however, the increase is only 3.6 percent of total production. Table 6-5 - Plant Species Composition (%) for Native Rangeland, July 2009 2006 2007 2008 2009 Change from 2008 to 2009 Perennial Grass 56.9 56.4 51.35 53.58 +4.2% Perennial Forbs 10.5 10.9 17.81 17.46 -1.9% Annual Grass 1.9 1.9 2.07 2.56 . +19.1% Weed Forbs 1.1 1.7 0.82 1.07 +23.3% Shrubs 29.6 29.1 27.95 25.33 -9.3% Total 100 100 100 100 ------ Values for plant species composition (Table 6-5) have only been measured since 2006. These values are based the above ground biomass production for each species and determined by each species contribution to total biomass production. Perennial grass and native forbs remain fairly consistent with previous years. Composition of native shrubs declined in 2009 due to their 15.6 percent decline in biomass production in 2009. Monitoring Results for Reclaimed Well Pad Sites Above ground biomass production, plant species composition and ground cover data were collected from three reclaimed well pad sites, 1 A-4HI, 3A-4H and 4-314, on July 27 and 29, 2009. All three sites were fenced to exclude grazing use from livestock. The data were collected from within ten 9.6 square foot quadrates randomly placed within each reclaimed well pad at the peak of production for most of the plant species within the study areas. Biomass production was measured using a double sampling procedure of estimates adjusted by actual values from representative samples. Three of the ten quadrates within each reclaimed well pad were estimated then clipped to derive an actual green weight correction factor used to adjust estimated green weights. Clipped samples were oven dried to obtain an air-dry weight correction factor for green weights. Ground cover values were made from visual observations of cover type within each quadrate and reported as a percentage of total ground cover. Biomass production, species composition and ground cover data for each site is summarized from the data presented in the appendices for each reclaimed well pad, Table A2 for pad 1 A-4141, Table A3 for pad 3A-4H and Table A4 for pad 4-3H. The ground cover data in these tables are shown by plant species or cover type. The annual above-ground vegetation biomass production is shown for each plant species encountered at each site. The species composition data is shown for each plant species encountered and determined by each species contribution to total biomass 2009 Annual Report 16 of 33