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Weed Control Issues: Leafy spurge remains dominant throughout the site, especially on the north <br />end just south of Quincy Avenue. It can still be found in essentially every habitat on the site except <br />reclaimed mined land, upland sand neaz mining sites, and in the wetlands along the stream. However, <br />an interesting pattern emerged this yeaz with the removal of grazing and the robust growth of the <br />grasses. <br />In areas where the bromegrass was common and in the somewhat drier locations where <br />western wheatgrass was common, the spurge showed a dramatic decline in its presence. The <br />bromegrass along the outer portions of the riparian corridor was often three to four feet tall and so <br />thick it was difficult to walk through. The spurge was still there, but the shade and competition had <br />weakened it so much in some areas it did not even flower and without flowers there was no seed <br />produced. Of course, there is still seed from previous seasons in the soil. Whether that ever <br />germinates though will depend on whether a favorable germination environment occurs. And <br />whether that will develop into mature plants depends on the presence of a favorable growth <br />environment. So long as grass density limits spurge growth and replacement, the future of spurge <br />presence in this locations is naturally hindered. This is reflected in the spurge control and <br />rehabilitation method usually recommended. After reducing the spurge growth it is important to <br />plant a crop of competitive grass to limit the return of the spurge. Here, in some locations, natural <br />growth in response to a removal of grazing pressure is limiting to continued survival of the spurge. In <br />that sense, the grazing was influential in the maintenance of spurge through the reduction of the <br />vigorous grass growth needed to limit the spurge population. <br />In a few locations spurge even failed to show much vegetative growth. In the western <br />wheatgrass dominated vegetation, the spurge also declined but did successfully flower. However, its <br />abundance was only a fraction of what had been seen in previous yeazs. Whether this is a temporary <br />condition or more permanent shift in the spurge population only time will tell. But clearly the good <br />growth year and the removal of grazing so competition from perennial grasses can increase has had <br />some effect on reducing the spurge population. To some extent, this was expected, but what was not <br />expected was such a dramatic decline over such a short period of time. <br />The Tamarix population treated last year returned to a very limited extent. There was some <br />recovery of plants previously thought to be dead and a few new plants appeared. But this population <br />is still about 5% of what it was in 2006. Nevertheless, because the goal is eradication treatment will <br />need to continue along with continued examination of other areas for new populations. At this point, <br />no new populations have been found. <br />2007 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 3 <br />