2009-01-30_GENERAL DOCUMENTS - C1980005

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were located every 20 in along the transect, for a total of 12 quadrats (6.0 m2 per plot). In the smaller plots at Seneca Mine quadrats were located every 10 in along each transect for a total sampling area of 4.5 m2 (9 quadrats) per demonstration plot. Within each of these quadrats all shrubs were identified to species and heights of individuals were recorded. At the Seneca Mine shrub tubelings were planted in September of 2000 in select demonstration plots. To evaluate the success of this operation, survival of transplants was quantified during the vegetation sampling. Shrub survival within each demonstration plot was estimated by following rows of transplants and scoring seedlings as either alive or dead. A minimum of 25% of the transplant rows within each plot was surveyed as such. During the vegetation sampling, voucher specimens of plant taxa were collected for positive identification and for archival in the Restoration Ecology Lab Herbarium. Permanent photo reference points established in 2001 in each demonstration plot were photographed annually to illustrate long-term changes in the vegetation. RESULTS AND DISCUSSION Results from the demonstration plots illustrate the complex interactions of various cultural and environmental factors in the establishment of woody vegetation on reclaimed surface mines. Shrub establishment and seeding success has been variable across the three mine sites (Figure 5, Table 9) likely owing to timing of the seeding, spoil quality and variable local climatic conditions at the three sites after seeding. Figure 5. Various non-topsoiled plots at Colowyo (left), Trapper (middle) and Seneca (right) mines in June 2004 showing differing shrub establishment success. Note the numerous sagebrush seedlings in the Colowyo photo (right). Shrub establishment at Trapper mine has been relatively slow, likely due to dry conditions after the spring 2001 seeding (plots were scheduled to be seeded in the fall or early spring but conditions precluded the seeding operation until April). However, by 2004 shrubs and other seeded species were beginning to appear at the Trapper plots (Tables 9 and 10). Most of the vegetative cover in demonstration plots at Trapper continues to be weedy invasive species (Table 10) such as Russian thistle, tall tumble mustard and Japanese brome. The recent appearance of cheatgrass as well as the persistence of Japanese brome in the Trapper plots may pose a threat to the establishing shrubs. The low levels of phosphorus in the spoil material at Trapper mine may have contributed to the lack of plant establishment in plots 4 and 5, which did not receive topsoil. Of the three sites, shrub establishment has been greatest at Colowyo mine (Table 9). Establishment of mountain big sagebrush, the dominant late-seral shrub in the region, has been very good in all plots at Colowyo (Table 13). Although shrub densities have declined from initial levels, this natural thinning of the shrub population should be expected in this habitat. The fenced portion of plot 4 at Colowyo had a dramatic increase in shrub density in 2004 (an increase of about 100,000 shrubs per acre) due to the establishment of seeded silver sagebrush. This delayed establishment of silver sagebrush illustrates the potential for seeds to persist several years before germinating. Results from Colowyo mine indicate that the autumn 2000 seeding operation was successful as most of the seeded species continue to be found on the site in 2004 (Table 12). Lewis flax, big sagebrush and common yarrow are seeded species, which have established in all plots. The seeded grass species are also well established. The weedy invasive species Russian thistle, which was dominant in previous years, has been reduced to a minor component in 2004. The appearance of weedy invasive cheatgrass and Japanese brome at Colowyo in 2004 is of concern for arresting development of the native component.