2015-02-17_REPORT - M1977227 (2)

Home Browse Search

The central flat area with the run -of -mine scoria surface has notably lower plant cover. This ar- ea presents more of a challenge to revegetation due to the run -of -mine scoria rock surface and flat expanse without notable micro - topographic relief. This area averages 10 to 15% vegetative ground cover (Photo 6). Shrubs in this area have been slower to grow and regenerate than the remainder of the site. This may be due to the lower moisture retention of the substrate and a greater surface temperature during the summer days from the dark surface and lack of topo- graphic relief. One portion of the Central Flats had very low cover at 5 to 10% with some areas bare (Photo 7). Vegetation Diversity Plant species diversity was good during the 2014 inspection and has continued to increase since the 2008 reclamation effort (Table 2, Photo 8). Dominant plant species shifted from grasses in 2012 to shrubs and blazing star (Mentzelia laevicaulis; Photo 9), which is a perennial herbaceous plant, during 2013 and remained during 2014. The dominant shrubs were four -wing saltbush (Atriplex canescens), green rabbitbrush (Chrysothamnus viscidiflorus) and broom snakeweed (Gutierrezia sarothrae). These plants are generally less or non - palatable to grazing livestock. One grass, blue grama (Bouteloua gracilis), continues to be a dominant plant species due to its low growth habit that is more resistant to cattle grazing. Table 2. Vegetative Diversity Values, Mesita Hill Mine, June 2014 Area Diversity (# of species) NE hills 8 Main Pit 4 North hills 6 Central, flat 5 NW hills 6 West side (with spread topsoil) 4 SW hills 5 S hills 10 SE hillock 4 Other plant species present on the site included the grasses western wheatgrass (Pascopyrum smithii), and Indian ricegrass (Achnatherum hymenoides). Also present were wirelettuce (Stephanomeria tenuifolia), buckwheat (Eriogonum deflexum, bottlebrush grass (Hordeum jubatum) and winterfat (Krascheninnikovia lanata). Some plants, particularly the grasses, were clipped, presumably from grazing by cattle and wildlife. M