Laserfiche WebLink
<br />Vegetation Study.' New Horimn Mine, NewAirpoR Re/erence Area (DMand Pasture) <br />5.0 RESULTS <br />Vegetation Cover <br />Table 1 shows percent cover for individual substrate types and plant spedes by trensect, and <br />means and relative cover for the reference area as a whole. Table 2 shows the same data <br />summarized for unvegetated substrates and planispecies groups. . <br />Table 3 compares mean percent cover for plats species groups between the new reference <br />area (measured in May 2005) and the adjacent old reference area (measured in eady fall 2000). <br />Total live perennial cover was almost identical. Total vegetation cover was higher at the new <br />reference area (34.3%, compared to 20.3% at the old reference area). The difference results <br />mostly from greater cover of annual forts and noxious weeds (most of which were also annual <br />forts) at the new reference area, attributable to the spdng sampling pertod early in the growing <br />season before ephemeral forts have senesced. The sprang of 2005 has also been <br />charectedzed by unusually high predpitation and relatively cool temperatures, encouraging <br />abundant growth of annual plants. <br />Vegetatlon Production <br />Table 4 shows production data For the new reference area, and Table 5 compares mean <br />production by plant category between the new and old reference areas. Total live vegetation <br />production was similar between the two areas, with production at the new reference area (493 <br />• poundslacre).exceeding production at the old reference area (447 pounds/aere). Compared to <br />the old reference area, the new reference area contains substantially less production of grasses <br />but more production of shrubs and espedally forts. <br />D'dferences in sampling dates between this study and fhe 1999 measurements at the old <br />reference area have-ta betaken into account to interpret production data. Measurements for <br />this study in late June were taken before the late-summer peak of production for perennial <br />plants, but earty enough that annual plants, p~rtic~~~~~~rr some robust annual forts, still <br />contributed signifigngy to live biomass. The 195'hY~asurements were made in late summer, <br />when perennial vegetation production was at or near fts peak but otter most annual forts and <br />grasses had senesced. Sampling date differences explain part of the differences in production <br />between the two reference areas, particularly wdh respect to annual vegetation, but the new <br />reference area.dearty has a more even mix of gresses, forts, and shrubs. <br />6.0 CONCLUSIONS <br />The old and new reference areas are adjacent, encompass nearty identical ecological site <br />condttions, have similar land use histories, and have similar plant spedes composition. This <br />study indicates that the new reference area has lower shrub and perennial grass cover than the <br />old reference area but greater perennial fort-cover, and that total live perennial cover (exduding <br />noxious weed spedes) is very similar between the two areas. Vegetagon production between <br />the tow areas is also similar, wtth slightty greater production at the new reference area <br />characterized by greater fort production and less grass production compared to the old <br />reference area. Because total cover and production at the two sRes are very similar, and the <br />BIO-Logic EnHronmoirtal 4 <br />Jury 2005 <br />• <br />(Revised August 2006) Attachment 2.04.10-4-5 <br />