Laserfiche WebLink
In the Wadge Pasture area, relative cover by perennial grasses rose 10 percent between 1991 <br />and 1992 while relative cover by forts fell by nearly 5 percent. In 1993 perennial grass <br />cover increased about 7 percent, while perennial fort cover remained constant, with a shift of <br />about 4 percent cover from introduced perennial (orbs to native perennial (orbs. These data <br />further suggest a pattern of reduced cover and increased production in 1992 caused by the <br />decline of decumbent (orbs, especially alfalfa, that provide much cover, along with an increase <br />in tall grasses providing relatively little cover with relatively high production because of their <br />height. Over the period of 1988 to 1992 in the Wadge Pasture, the percentage of total <br />vegetation cover provided by perennial grasses has risen by about 10 percent while perennial <br />forts, primarily alfalfa, has fallen by 10 percent. However, this proportion has fluctuated <br />such that as of 1991, the percentage of vegetation cover in perennial grass was almost exactly <br />what it was in 1988, but it suddenly increased again by 1992, and then decreased in 1993. <br />Thus, it is clear that the relative proportion of grasses and forts is dynamic, changing as <br />environment favors one or a few species or lifeforms, and then other species or lifeforms. <br />After seven years, the Wadge Pasture area seems to have had few if any ill-effects concurrent <br />with livestock grazing, and in fact exceeds all other reclaimed areas in the pertormance <br />• standards of vegetation cover, biomass production, and shrub density, and as of 1993 has <br />substantially increased in species density (diversity) to a level comparable to the reference <br />areas. <br />Over the period of 1988 to 1992, the Wadge Pasture has had a consistent introduced species <br />density of about 9 species per 100 sq. m.; in 1993 that rose to 11 species per 100 sq. m. <br />Native species density has increased between 1988 and 1992 from about 10 species per 100 <br />sq. m. to about 12 species per 100 sq. m.; in 1993, it rose to 16 species per 100 sq. m. Thus, <br />among the effects of grazing over the past five years is a 60 percent increase in average native <br />species diversity, as reflected by species density data. <br />Precipitation data by month from the Seneca II Mine for 1987, 1988, 1989, 1990, 1991, <br />1992, and 1993 as well as the 10-year average for the mine are shown in Figures 6a and 6b. <br />As can be seen in those graphs, following an extremely wet July in 1992, January and April <br />1993 were also wetter than average, suggesting the presence of favorable soil moisture storage <br />conditions as the 1993 growing season got underway. <br /> <br />32 <br />