REP31696 - Laserfiche WebLink

Home Browse Search

~ m. RESUI,Ts In 1997, conditions at the mine site were much drier than normal. Spring and summer were very dry, with the mine site receiving only 6.47 inches of precipitation between January 1 and July 31. This represents 2.20 inches less precipitation during the same period than in 1996. As would be expected, herbaceous plant growth and development was severely hindered by the lack of moisture. Inspections of the site in June and July 1997 revealed that the majority of both cool and warm season grasses had not reached anthesis. Vegetative growth of the majority of grasses and forts was noticeably less than in previous seasons. By mid August, anthesis was apparent in approximately thirty percent of the warm season grasses. As many of the spring ephemeral species were dried by this time, sampling proceeded so as not to lose further representation of the cool season grass and fort component. Total vegetation cover and herbaceous production values were significantly lower than previous years in all areas due to the dry weather. Four lifeforms were encountered during the sampling of the reclaimed and reference areas. They included graminoids, forts, succulents, and woody shrubs. Twenty-three individual species were identified during sampling at the reference and reclaimed areas. • The dry spring and summer resulted in fewer total plant species being encountered during the cover sampling in the reclaimed areas, and represented a 26 percent average decrease in total plant species encountered from 1996. The total number of species encountered on the Osgood Sand Reference Area remained relatively consistent, with one additional species being encountered this year (11 species 1996, 12 species 1997). The plant species encountered and their locations are presented in Table 1. OSGOOD SAND REFERENCE AREA The Osgood Sand Reference Area represents approximately 3.4 acres of undisturbed native vegetation within the Keenesburg Mine permit area. The reference area is sited immediately west of the mine access road and has been fenced to prevent grazing by domesticated livestock. The reference area is flat and exhibits sheet flow drainage to the east-southeast. Soils were generally sandy in texture, with very little incorporated organic matter. The vegetation community was visually dominated by the woody shrub Artemesia 61i1olia (sand sage) and the graminoid Stipa viridula (green needlegrass). While not dominant by stature, Bouteloua graci/is (blue grama) was found to be present throughout the reference area. Several minor annual fort species were present this season. The number of species represented in cover sampling increased from eleven (11) in 1996 to twelve (12) this year (Savage and Savage, 1996). Specific sampling • information for the reference area is contained in Tables 2 and 6. -5-