2008-07-15_REPORT - M1988044 - Laserfiche WebLink

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i I ' exhibited some continued growth. Grasses were strongest adjacent to more or less denuded areas such as roadsides, around ant hills, and in old vehicle paths. These microtopo0aphic variations generated places where the limited moisture tended to accumulate, generating a highly localized, ' more favorable growing environment. But a few feet further into the grassland and the effect was totally lost resulting in limited or essentially no growth. j Seeded areas in 2006 that germinated in 2007 showed very weak development due to the dry winter and spring. All the revegetation areas are continuing to be amazingly free of noxious weeds, although annual weeds are still common in the younger growths. The invasion of Tamarix detected in 2006 ' has largely been controlled with continued clean up of a few remaining plants. As of the date of thi's 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. Wetter conditions can allow dormant seed to germinate and a return of the infestation. The increased moisture in 2006 and 2007 along with the removal of grazing, benefitted the ' grasslands as well as the lowland areas. Weed density, although still high, is reduced as a result of the heavily grazed native grasses coming back with strong growth in the last half of 2007. Even the needlegrasses in heavily grazed areas made a good showing in 2007, although in most areas they ' were not the dominant species. The dominant grass is still blue grama in most upland areas. But there appears to be some shift toward the needlegrasses. Because there is no quantitative data that defines the species frequency distribution during grazing or after, it is hard to say that the apparent ' shift in the species is real or an illusion. One thing is clear, though, and that is the productivity of the grasslands has increased. 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 much real ' change in the species frequency distribution or density. But with the large amount of seed produced in 2007 that should eventually translate into a shift in the species frequency distribution. It may take a few years for that to actually be seen as precipitation has been too limited to induce much ' germination. The simple fact that so much seed was produced in the good growing year of 2007 is positive. The five new riparian exclosures were quantitatively sampled in early September 2007. ' 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 estimated as, on the whole, about doubling in the last year. Some trees grew over six feet, but most gained one to three feet in height with even larger gains in leaf volume. 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. Non-protected riparian vegetation also made excellent gains and appears to be catching up with the protected growths. Clearly, the grazing impact on the riparian corridor was very ' severe and was the primary, if not the only factor involved in the lack of recovery' of the riparian vegetation. This was suspected several years ago and now that the grazing has been removed that suspicion confirmed as true. i STATUS REPORT FOR CURRENT YEAR ' MAPS: Following is a list of the maps that have been updated. The maps provided with this report are intended to replace the previous map. Maps that do not require updating are also listed. Maps that are not updated therefore become the current year map. ' Status report for 2007 (July 15, 2007) Page 2 of 10