2009-07-15_REPORT - M1988044 (2)

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production of existing plants is sufficient, but these areas might also require some spot seeding next year or perhaps this fall. All the revegetation areas are continuing to be amazingly free of noxious weeds, although annual weeds are still common in the younger growths. The frightening invasion of Tamarix detected in 2006 has largely been controlled with continued clean up of a few remaining plants. As of the date of this report it is estimated there are only about 50 plants left and very few seedlings have been found. Continued inspection will be necessary though as this species, once established, is very tenacious. The few plants that are left seem to be very determined to remain and seem to be moderately unresponsive to control efforts. Fortunately, none are large plants and that provides an opportunity to physically remove them by simply hacking them out of the ground. The increased moisture in the spring along with the removal of grazing, has continued to benefit the grasslands as well as the lowland areas. Weed density, although still high, is much reduced as a result of the heavily grazed native grasses coming back with strong growth in the last couple of years. The needlegrasses in heavily grazed areas have returned to a high density, and are now the dominant species in many areas. Blue grama in most upland areas is still very strong, but there appears to be shift in the species composition more toward the needlegrass and even some bluestems. Because there is no quantitative data that defines the species frequency distribution during grazing or after, it is hard to say whether the apparent shift in the species is real or an illusion caused robust plants. Although the needlegrasses dominate the view, it is not known whether they are numerically dominant. One thing is clear, though, and that is the productivity of the grasslands has increased remarkably since the removal of grazing and appears to be shifting back somewhat more toward a needlegrass-wheatgrass-bluestem-grama grassland. Of course, this is most likely just a result of the removal of grazing which was utilizing the grasses. It is unlikely that over such a short period of time there has been a great deal of real change in the species frequency distribution curves. But with the large amount of seed that should be produced in 2009 that should eventually translate into a shift in the species frequency distribution. The excellent growth year in 2009 will undoubtedly accelerate this shift. It is important to note that in the 2008 planted areas, one of the most successful species was needlegrass with western wheatgrass and/or blue grama hanging on to a tight second place. This is important because as the undisturbed (by mining) grasslands begin to shift more toward a needlegrass dominance with wheatgrass and grama close subdominants, the revegetation areas seem to be also trending in that direction. In time, this should allow a closer compatibility in the species structure between revegetated areas and undisturbed areas. It will take many years for that to fully develop, but so long as the structure of these two vegetation units trend toward structural convergence then eventually the reclamation should be indistinguishable from the- natural vegetation. The five new exclosures were quantitatively sampled in early fall of 2008. Analysis of the data and comparison to previous data showed very significant gains in growth. The protection of the trees has reaped considerable benefit with woody biomass increasing about 50% as compared to the previous year. The large gains of 2007 were not seen due to the dry summer. In fact, among the older trees along the stream bottom, by the end of August there was considerable dieback of leaves on outer branches and for most of the summer the trees looked somewhat wilted. The wilted appearance declined in September as more moisture arrived, but many outer branches of the old, mature trees were lost. The younger woody growth continued to show the typical instability of an immature growth, but evidence that the willows and cottonwoods were "sorting things out" became apparent with each establishing a moderate degree of zonation typical of mature growths. It is significant that even with the dry summer the woody growth in the new generation remained strong even with the Status report for 2009 due July 15, 2009 Page 2 of 10