_GENERAL DOCUMENTS - C1981017 (227)

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Reference Area No.2(on west slope of Sutev Refuse Pile) Noxious species absolute cover declined significantly from 1998 to 1999,with a non-significant increase from 1999 to 2000. The apparent increase from 1999 to 2000 is most likely due to maturation of surviving thistle and houndstongue plants that were small basal rosettes in 1999. There has been a highly significant decline in noxious species density each year. Based on comparison of sample means,noxious species density has declined approximately 83%from 1998 to 2000. Total vegetation cover was higher than 1999,due to increased grass cover,but remained below 1998 level. Relative cover of grasses has increased from 7.8%in 1998 to 44.8%in 2000,with a corresponding decline in relative cover of non-noxious forbs,from 65.5%in 1998 to 37.2%in 2000. Reference Area No. 3 (along reclaimed beltline flat) In contrast to an increase between 1998 and 1999,noxious species absolute cover declined significantly between 1999 and 2000. There was a highly significant decrease in thistle density between the previous years and 2000. Based on comparison of sample means,thistle density has declined approximately 95%from 1998 to 2000. Some oxeye daisy remained in the plot in 2000,but density was not estimated. Oxeye daisy density will be estimated in 2001,along with thistle density. Total vegetation cover was similar to 1999. Relative cover of grasses increased,while relative cover of noxious species declined,and relative cover of non-noxious forbs remained stable between 1999 and 2000. Because 1998 was the first growing season,cover comparisons between 1998 and subsequent years are not particularly meaningful. Reference Area No.4(beltline outslope adjacent to Reference Area No. 3) Although noxious species cover values were somewhat higher in 2000 than in 1999,the data illustrate the dramatic decline between 1998 and the present,which is visually readily apparent. Prior to initial treatment,noxious absolute cover was 41%,with relative cover of 59.4%. In 2000,noxious absolute cover was 7%,with 13.7%relative cover. Relative cover of grasses increased from 14.4%to 70.6%,while relative cover of non-noxious forbs and shnibs combined decreased from 25.9%to 15.7%over the period. Summary Effects of spraying are more uniformly evident in each of the reference areas than was the case last year, with target species reductions approaching control program objectives. Based on visual reconnaissance, response of the target species within the sampled reference areas appears to be representative of the response within the larger treatment areas in which they are included. 2000 may be the final year that spraying and other treatments are necessary at the Sutey Pile and vicinity, and beltline corridor,depending on 2001 data and observations.