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respect to floristic dominance in the vegetation, species that tend to be dominate in the most highly developed wetland units are also dominate or at least sub-dominate in the most poorly developed wetland units. That is, the dominate species tend to occur practically everywhere that wetland is present. It is also very interesting to note that in Table 1 only one species tends to be a problem species, Hordeum jubatum. But even that species is not abundant and is most commonly found on the wetland side of broad transition zones from upland to wetland. Out in the wetlands themselves this species is rarely found. No other problem species or noxious weeds were found in any of the wetlands. That does not mean they are not there, but if they are there they have a very low abundance. This is interesting because the surrounding lands contain a large number of noxious weeds, some of which can invade wetlands. There has been sufficient time for such invasion to occur, and yet it appears it has not occurred, at least to a level that makes them noticeable in the vegetation. Canada Thistle, in particular, is fairly common in dense, isolated patches throughout the valley and it can quite readily invade wetlands, even very wet areas. Yet not a single plant was seen in any recovered or natural wetlands. It might actually be there, hiding among the taller plants, but if that is the case it certainly is not a problem species and is probably having a difficult time competing with other, better adapted species. Over half of the species noted are obligate wetland (OBL) species and nearly all of the rest are almost obligate (FACW). Only two species tend to sit on the fence between wetland and upland (FAC) and one species is almost upland (FACT)). This tends to indicate the wetlands are well developed and are maintained by a rather consistent moisture regime. Wetlands that have highly fluctuating moisture levels tend to have fewer obligate wetland species and more of the FACW and FAC species. Natural vs. Recovered Wetlands When natural wetlands that occur in the stream channel, particularly those found on the south end of the study area near the county line, tend to be quite similar to the recovered wetlands with regard to dominate species and the high proportion of obligate wetland species. Scirpus and Juncus are the dominate species within these natural wetlands. Furthermore, the natural wetlands are consistently found where the sand layer is thin or absent. In the recovered wetlands as well as in the enclosures, this pattern is also consistently found to be the case. In the herbaceous vegetation, it is difficult to see any differences between the recovered wetlands and the natural wetlands. Where the environment is similar the wetlands living there, whether recovered or natural, are essentially interchangeable. This indicates that there is no real difference between natural wetlands and wetlands that developed in areas where the sand layer was removed and the underlying clay left in place. Furthermore, this development occurs quite rapidly taking only about three or four Creek Wetlands and Wetland Mitigation DA Permit 198811488 August 2003 Page 13 of 23