2010-12-29_REPORT - M1988044 - Laserfiche WebLink

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The soil here is decidedly more sandy than Exclosure 1, but over most of the site Juncus balticus is still at least moderately abundant. In 2009, Equisetum sp. also showed a large gain in presence while it had been scarce in previous years. It is apparent there is a fairly good groundwater support, but in some of the more elevated mounds the distance to groundwater diminishes just enough that there is less growth in the pure sand. Cattle impact here had been severe in the past as the cattle frequently grazed in the wetland to the west where there is good forage and available water. Most of the larger woody plants were heavily browsed by the cattle. Those had a good root system, but little top growth. In 2006 (the first year of this study) there were a fair abundance of smaller cottonwoods and willows that showed only minor to moderate browsing impact. In 2007, herbaceous growth increased dramatically over the entire area, mainly as a result of the wet growing season. But woody growth also made considerable progress with a great deal of recovery from previous browsing impacts. Leaf density on the trees and shrubs increased dramatically and with the additional food producing tissues growth of new shoots as well as existing shoots increased some. However, growth was not as prominent as might be expected as the plants were undoubtedly putting a lot of energy into producing more short branches and leaves. In 2008, the overall vegetation development trends seen in 2007 continued, but at a somewhat less dramatic pace. In part this reduced development rate was due to the rapid recovery in the first year after the removal of browsing which increased density up to near the holding capacity. Woody plant growth however showed strong gains, in spite of the dry 2008 growing season. It appears that these plants are starting to tap into the groundwater to a much higher degree. Overall, woody species density here is obviously far less than in Exclosure 1. Here the woody plants are widely distributed over the site, except for the very dry, sandy locations where only scattered grasses are found. Results of Sampling: The graphs on page 14 show the trends for this exclosure. As stated before, the presentation format is the same as that used for Exclosure 1 and the other exclosures. That is, the emphasis is on a comparison of all the years rather than on the current year. From the first graph which shows changes in height over the study term, a different pattern appears when compared to Exclosure 1. The gains here continued along essentially a straight line extended from previous years. That indicates that growth in 2010 proceeded steadily and with minimal limitations due to density. As the plants are fairly widely distributed with only moderate amounts of clustering this steady, non-competitive growth pattern is understandable. Tree density remains low in comparison to other exclosures and this undoubtedly is due to the drier character of the habitat. Nevertheless, growth rates and gains in height are good. However, the second graph exhibits an interesting pattern that also shows some room for concern. Although the percent gains in average and maximum height was huge in the first year, the percent increase has declined in subsequent years. It is still showing good gains, but the decrease is prominent. 2010 Annual Report Coal Creek Wetland Mitigation Permit DA 198811488 Page 12