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Level 3 Potential Conservation Area (PCA) Report <br />Name Rare Plants of the Chalk Barrens Site Code S.USCOHP8 *3283 <br />includes pinon -juniper woodlands (Pins edulis and Juniperus monosperma) and shrublands with Bigelow <br />sagebrush (Attemisia bigelovil) and/or James' frankenia ( Frankenia jamesb) as well as <br />herbaceous- dominated patches. The landscape surrounding the barrens is a mix of pinon -juniper savanna <br />interspersed with grasslands. The site contains extensive old growth stands of juniper and pinon - juniper <br />savannas with New Mexico feathergrass (Hesperostipa neomexicana), side oats grams (Boute/oua <br />curtipendula), and ring muhly (Muhlenbergia torreyi). Grasslands are dominated by galleta grass (P/euraphis <br />jamesit) and blue grama (Bouteloua gracil/s). Scattered shrubs include cholla cactus (C)/indropun6a <br />imbricata), founaing saltbush (Atriplex canescens), and winterfat (Krascheninnikovia Janata). The portions of <br />the site north of Highway 50 are generally less dissected by development and roads than the portions along <br />the Arkansas River. North of Highway 50, especially in the Beaver Creek area, taller grasses, including New <br />Mexico feathergrass, occur. The Arkansas River runs through the site, and supports riparian vegetation <br />dominated by cottonwood (Popu/us de/toides) degraded with invasive non - native plants including tamarisk <br />(Tamarnr ramosissima) and Russian olive (8aeagnus angusdfolia). <br />Key Environmental Factors <br />Outcrops and barrens of Late Cretaceous sedimentary bedrock embedded in a landscape mosaic of <br />grasslands, dwarf shrublands, and pinon - juniper woodlands and savannas. <br />Cllimate Descriatlon <br />No Data <br />Land Use History <br />No Data <br />Cultural Features <br />No Data <br />SITE DESIGN <br />Site Map P - Partial Mapped Date 12/10/2007 <br />Designer Neid, S.L <br />Boundary Justification <br />The boundary encompasses the concentration of element occurrences plus unsurveyed, apparently suitable <br />habitat in the vicinity of the occurrences. Basinwide vegetation data (CDOW 2001) for the Arkansas River <br />were used in conjunction with the element occurrence data to design the site boundary. Most of the element <br />occurrences fall within the "Sparse Pinon Juniper /Shrub/Rock Mix" basinwide vegetation mapping unit <br />Kelso and others (2003) noted that the Middle Chalk and Upper Chalk units of the Smoky Hills Member of <br />the Niobrara Formation are the most botanically important barrens of the area. Fine -scale geologic data <br />delineating members of formations was not available when designing the site boundary. In general, site <br />boundaries are drawn to represent our best estimate of the primary area needed for the survival of the <br />occurrences. This area is sufficiently large to protect intact (or at least allow simulation of) most of the <br />natural ecological processes necessary for survival of the species, including fire, herbivory, and hydrology. <br />The boundaries also include the mosaic of local community types on which the species may rely. <br />Primary Area 87,952.92 Acres 35,593.43 Hectares <br />SITE SIGNIFICANCE <br />Biodiversity Significance Rank 61: Outstanding Biodiversity Significance <br />Bfodiversity Significance Comments <br />This site is a botanical hotspot and contains excellent (A- ranked) and good (B- ranked) occurrences of four <br />globally imperiled (G2/S2) plant species: round -leaf four - o'clock (Oxybaphus rotundifolius), golden blazing <br />star (Muttallia chrysantha), Pueblo goldenweed (Oonopsis pueb/oensis), and Fendler's townsend -daisy <br />(Townsendia fend/en). The site also contains excellent (A- ranked) and good (B- ranked) occurrences of the <br />globally vulnerable (G3 /S3) Bameby's fever -few (Bo/ophyta fetraneuris), Rocky Mountain bladderpod <br />(Lesquerella ca /cico /a), Arkansas Valley evening primrose (Oenothers harringtonii), and dwarf milkweed <br />(Asclepias uncialis spp. unciahs), and excellent (A- ranked) occurrences of frankenia / Indian ricegrass <br />(Faankenia jamesii / Achnatherum hymenoides) communities (GU) and the common one - seeded juniper/ <br />New Mexico feathergrass (Juniperus monosperma /Hesperostipa neomexicana) woodlands. High <br />concentrations of rare plants merit an outstanding biodiversity significance rank. <br />Other Values Rank No Data <br />Other Values Comments <br />Nice views of the Wet Mountains, Pikes Peak and the expansive plains are afforded from the site. <br />Copyright © 2014. Colorado State University. Colorado Natural Heritage Program. All Rights Reserved. <br />Prink Date 1212' 2014 <br />