REP44198 - Laserfiche WebLink

Home Browse Search

the degree to which these extremes are sampled could create apparent differences that do not reflect changes in the true shrub population of the Wadge Pasture. Of additional note in the shrub density sampling results for 1993 was the presence in the 1989 Reclaimed Areas of 21 stems per acre of serviceberry and 5 stems per acre of bitterbrush. Species Diversipf and Com sition Species density reflects the total number of species present (richness) in 100 square meters adjacent to cover sample transects. Species density data are summarized in Table 24 and graphically presented in Figure 4. As can be seen in Figure 4, as well as the data in Table 24, the total species density of the reference areas in 1992 is in the range of 31 to 32 species/ 100 m2. Both the 1989 Reclaimed Areas and the 1991 Wadge Pasture equaled this level of overall species density. In terms of native species density, the reclaimed area values (including the Pre-law reclaimed area) varied from 11.6 to 20.0 species per 100 m2 in 1993, 12.1 to 19.0 species per 100 m2 in 1992, compared to 9.9 to 18.3 species per 100 m2 in 1991, and 9.5 to 18.9 species • per 100 m2 in 1990. This compared to 1993 Mountain Brush and Sagebrush reference areas values of 28.6 and 29.0 species per 100 m2, respectively; 1992 values of 33.9 and 24.6 species per 100 m2 ,respectively; 1991 values of 28.7 and 27.7 species per 100 m2 , respectively; and 1990 values of 22.9 and 25.9 species per 100 m2 ,respectively. The highest reclaimed area values have climbed slowly since 1990, but do not yet equal the levels of native species density found in the reference areas. The increase in species density over the years may indicate that plant succession is proceeding in these reclaimed area plant communities and that equality with native areas may eventually develop. The highest native species density observed in 1993 in the reclaimed areas was 20.0 species per 100 m2 in the 1997 Wadge Pasture, closely followed by the 1989 Reclaimed Area with 18.8 species per 100 m2 . In the Wadge Pasture, over the period that species density has been measured (1988 to 1993), species density of native plants has risen from approximately 10 species per 100 m2 to the 16 species per 100 m2 observed in 1993. When 1989 reclamation was last measured (1991), species density of native plants was 11.9 species per 100 m2 in fhe 1989 Wadge areas and 13.0 species per 100 m2 in the 1989 Wolf Creek areas. Thus, there has been a noticeable rise in native species density over periods of two to five years. 29