2019-05-14_PERMIT FILE - M2019025 (16)

Home Browse Search

ATTACHMENT D 4.0 COLORADO BUTTERFLY PLANT HABITAT CHARACTERISTICS The Colorado butterfly plant (Gaura neomexicana ssp. coloradensis) is a federally listed Threatened, short-lived perennial herbaceous plant. This threatened subspecies is distinguished from the New Mexico butterfly plant (Gaura neomexicana ssp. neomexicana) based upon differences in pubescence and its disjunct range (Rocky Mountain Heritage Task Force, 1987). All of the currently known populations of the Colorado butterfly plant occur within a small, 17,000 acre area in southeast Wyoming, western Nebraska, and north-central Colorado (USFWS, 2000; CNHP 2018). In Colorado, historic collections have been made in Adams, Boulder, Weld, Douglas, Jefferson, and Larimer Counties (CNHP, 2018). However, the only natural populations of the butterfly plant presently known in Colorado are at Meadow Springs Ranch and the adjacent Soapstone Ranch near Fort Collins, Colorado. This subspecies occurs primarily on subirrigated alluvial soils on level or slightly sloping floodplains and drainage bottoms at elevations between 5,000-6,400 feet (USFWS, 2000). The butterfly plant requires early- to mid-successional riparian habitat, and colonies are often found in low depressions or along bends in wide, active, meandering stream channels a short distance upslope of the actual channel (USFWS, 2000). It prefers open habitat that is not substantially overgrown by other vegetation, and in undisturbed sites it grows among native grasses (USFWS, 2015). The Colorado butterfly plant appears to require shallow subsurface water, and it is not found where streams are deeply incised (Rocky Mountain Heritage Task Force, 1987). 5.0 HABITAT ASSESSMENT METHODS AND DATES Heather Houston of Western Ecological Resource, Inc. completed the habitat assessment on May 15, 2018. The habitat assessment characterized the wetlands and adjacent mesic areas based on plant community descriptions, site geomorphology, soil surveys, hydrologic characteristics, ecological condition, and land use history. Heather is certified by the U.S. Fish &Wildlife Service to conduct surveys for the Ute ladies' tresses orchid. 6.0 RESULTS 6.1 Wetland A 6.1.1 Location, Hydrology and Vegetation Wetland A (0.61 acre) is located in a slough just north of the Big Thompson River and east of Weld County Road 13 (Photos 6 & 7). This wetland is a historic channel of the Big Thompson River. The seasonally saturated soil is supported by high groundwater. Shallow standing water was present at the time of the delineation after a period of heavy rains, but is likely present in most years. The vegetation is dominated by threesquare bulrush (Scirpus pungens) in the shallow water and saturated soil habitats, growing with Emory sedge (Carex emoryi), saltgrass (Distichlis spicata), foxtail barley (Hordeum jubatum) saltmeadow rush (Juncus gerardii), and variableseed saltbush (Atriplex heterosperma). In the drier soils near the margin, the noxious weeds quackgrass (Elytrigia repens), broadleaf pepperweed (Lepidium latifolium) and 3