2017-02-28_REPORT - C1981028 (30)

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Keenesburg Mine 2016 Vegetation Monitoring Report Annual species (both native and introduced) are able to take advantage of seasonal changes in precipitation patterns more quickly than perennial species. The September— July precipitation has been 40% or more above average for the past three years (2013-2014, 2014-2015, and 2015- 2016, Figure 4) which has provided for a flush of annual species. Particularly, the spikes in September and April -May precipitation gave a boost to cheatgrass and early spring annuals, such as prickly lettuce and Canadian horseweed, at the expense of the dominant warm season grasses. However, these early season spikes have also allowed for a little bit more cover of cool season perennial grasses which were almost entirely removed from this community after several years of drought. Figure 5: Absolute Cover of Native and Introduced Species 2014 — 2016 70 60 50 0 0 40 U 30 0 Q 20 10 0 _., 2015 2016 ; 2016 2015 2016 2014 2015 2016 2014 2015 2016 Area 23 ■ Perennial Native Area I Area 29 25 ■ Annual Native Area 30 ■ Annual Introduced Forbs Area 31 ■ Cheatgrass A pre -emergent herbicide was applied prior to the 2012 growing season in all of these areas which was credited with a large decrease in cheatgrass and other annual weeds in 2012 from previous years. However, in 2015, cheatgrass was a dominant species in in all of the Reclamation Areas comprising 26% — 28% of the relative cover in each area (Figure 6). This prompted another pre -emergent herbicide application in the fall of 2015 to Reclamation Areas 25, 29, and 30. This application appears to have been successful in Reclamation Area 29 where relative cover of cheatgrass fell from 26.3% in 2015 t0 18.5% in 2016. However, relative cover of cheatgrass increased from 2015 to 2016 in all of the other Reclamation Areas monitored (Figure 6). Habitat Management, Inc. 24 October 2016