AECOM 2.3-1

2.3 Vegetation Including Wetlands and Riparian Areas 2.3.1 Key Issues Key issues for vegetation resources include:

• Temporary and permanent loss of vegetation associated with surface disturbance; • Displacement of native vegetation by noxious and invasive species as a result of surface disturbance; • Potential long-term loss of wetlands and riparian areas as a result of groundwater drawdown; and • Potential decrease in plant species diversity within wetland and riparian areas in the long-term as a result of increased soil salinity related to the discharge of groundwater to drainages.

2.3.2 Study Area The study area for vegetation (including wetlands and riparian areas) includes all or portions of Sheridan, Johnson, Campbell, and Converse counties (Figure 1-1). This includes all or portions of 18 subwatersheds (fourth order). It also includes most of the area administered by the BLM Buffalo Field Office, a portion of the area administered by the BLM Casper Field Office, and a portion of the TBNG, which is administered by the FS (Figure 1-2). State and private lands also are included in the study area (Figure 1-3).

2.3.3 Current Conditions The Wyoming PRB study area is characterized as a mosaic of general vegetation types, which include grasslands, shrublands, forested areas, and riparian areas. These broad categories often represent several vegetation types that are similar in terms of dominant species and ecological importance. Northwest Regional Gap Analysis Project (NWReGAP) resources generated by the USGS were used to identify specific vegetation types within the Wyoming PRB study area. Sixteen vegetation types were identified, of which 12 primarily consist of native vegetation and are collectively classified as rangeland. These rangeland vegetation types include short- and mixed-grass prairie, sagebrush shrubland, saline shrubland, other shrubland, coniferous forest, deciduous forest, aspen, stabilized dunelands, forested riparian, herbaceous riparian, wet meadow, and wetland/fen. The remaining vegetation types support limited or non-native vegetation and include agricultural, urban/disturbed, barren, and open water. Figure 2.3-1 shows the vegetation types within the PRB study area and primarily was derived from NWReGAP data.

2.3.3.1 General Vegetation Table 2.3-1 provides the approximate acreages of pre-disturbance vegetation types present within the Wyoming PRB study area by subwatershed. Tables 2.3-2 and 2.3-3 provide approximate existing cumulative disturbance acreages for each of the vegetation types as a result of past and present development and approximate existing coal mine-related disturbance for each of the vegetation types, respectively, within the subwatersheds in the Wyoming PRB study area.

Short- and Mixed-grass Prairie The short- and mixed-grass prairie vegetation community accounted for approximately 31 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community is a combination of low, medium, and high herbaceous rangeland types that occur on a wide variety of landforms. Short- and mixed-grass prairie can be divided into several subtypes and is characterized by several common species including needle-and-thread grass (Hesperostipa comata), western wheatgrass ( smithii), blue grama (Bouteloua gracilis), buffalo grass (Buchloe dactyloides), prickly pear

Task 1D Report December 2012 AECOM 2.3-2

Table 2.3-1 Pre-disturbance Vegetation Types by Subwatershed

Vegetation Type (acres)

Fen

grass grass

and

- - ubland r Other Shrublands Coniferous Forest Deciduous Forest Aspen Stabilized Dunelands Agricultural Urban/ Disturbed Barren Forested Riparian Herbaceous Riparian Meadow Wet Wetland/ Water Short Subwatersheds Mixed Prairie Sagebrush Shrublands Saline Sh Total1

Antelope Creek 206,134 390,342 2,149 23 6,851 0 0 0 4,138 17,442 8,869 16,025 5,909 0 2,123 100 660,106

Clear Creek 184,523 257,244 2,914 3,556 19,383 426 3,408 0 41,863 7,578 3,944 8,782 9,623 14 548 3,674 547,481

Crazy Woman Creek 160,079 299,375 4,360 3,801 46,445 34 334 0 13,337 3,289 5,424 4,813 5,633 53 871 463 548,309

Dry Fork Cheyenne 111,280 157,993 4,041 14 596 0 0 1,132 9,847 1,947 11,600 6,868 3,188 0 707 135 309,349

Lightning Creek 87,823 188,051 6,252 2 0 0 0 0 11,446 3,956 2,448 5,117 1,875 0 1,118 217 308,303

Little Bighorn River 26,454 865 397 598 8,713 951 4,842 0 6,257 142 3 208 259 0 921 98 50,708

Little Missouri River 19,141 15,444 14 0 1,503 2 0 0 1,794 7 27 643 261 0 221 14 39,071

Little Powder River 385,087 347,408 1,024 21 43,391 3 0 0 37,209 14,152 6,382 10,896 13,966 0 6,018 275 865,832

Middle Fork Powder River 80,498 253,867 9,015 3,384 86,326 26 513 0 10,516 1,510 11,550 940 3,920 70 1,683 182 463,998

Middle North Platte River 54,591 107,226 5,298 0 5 0 0 31,869 940 942 6,602 3,256 1,129 0 434 6 212,299

Middle Powder River 74,902 100,505 336 2 29,569 0 0 0 6,129 351 2,969 5,246 2,401 0 1,633 271 224,313

North Fork Powder River 532 13,920 0 233 5,464 0 1 0 0 3 0 0 0 11 101 0 20,266

Salt Creek 22,436 112,211 2,803 19 3,032 0 0 0 194 695 7,522 1,767 808 0 196 30 151,712

South Fork Powder River 17,171 74,470 3,143 3,367 7,391 0 0 0 467 707 5,949 403 647 0 515 110 114,338

Upper Belle Fourche River 231,046 491,405 1,741 6 9,034 1 0 0 25,144 49,917 2,127 23,096 5,676 0 5,741 662 845,597

Upper Cheyenne River 58,847 116,038 476 96 3,785 0 0 0 3,385 16,774 2,693 1,705 391 0 2,957 240 207,387

Upper Powder River 297,576 1,154,880 6,495 3 29,275 0 0 0 22,484 12,130 34,670 23,034 19,723 0 2,578 652 1,603,499

Upper Tongue River 397,921 130,715 4,064 10,548 35,561 911 8,397 0 101,930 17,193 2,561 9,860 16,827 57 2,854 752 740,152

Total1 2,416,040 4,211,960 54,521 25,672 336,325 2,355 17,493 33,002 297,080 148,735 115,340 122,657 92,237 205 31,219 7,880 7,912,721 1 Slight differences in totals may occur due to rounding. Source: USGS 2010.

Task 1D Report December 2012 2.3-3 X:\0Projects\BLM_PRB_Phase_II_60143410\Figures\DOC\650_Task_1D_Report\Figure_2_3-1_VegCommunities_20121114.mxd

R89W R88W R87W R86W R85W R84W R83W R82W R81W R80W R79W R78W R77W R76W R75W R74W R73W R72W R71W R70W R69W T58N Bitter Cr. T58N

Prairie T57N Dog Cr. T57N

SHERIDAN Spotted Horse Cr. T56N Sheridan COUNTY T56N Little Powder River

Clear Cr. Burlington T55N Northern RR. Big Goose Cr. T55N

14/16

T54N Middle Prong T54N Little Goose Cr. 14 Wild Horse Cr. Wild Cat Cr. Cottonwood Cr.

T53N T53N

Wild Horse Cr.

Piney Cr. T52N T52N

Rock Cr. Burlington 16 Northern RR. T51N Crazy Woman Cr. Buffalo T51N

T50N Gillette T50N Powder River

North Fork Crazy Woman Cr.

T49N T49N I-90

T48N T48N Fourmile Cr. CAMPBELL FourHorse Cr.

Trabing Dry Cr. COUNTY T47N Timber Cr. T47N Pumpkin Cr. 59

T46N JOHNSON T46N

South Fork COUNTY T45N Crazy Woman Cr. Belle Fourche River T45N Bacon Cr. I-25 Union

Pacific RR. Red Fork North Fork T44N Powder River Powder River Dry Fork Powder River Black Thunder Cr. T44N Bear Trap Cr. Wright Kaycee T43N T43N Little Middle Fork Thunder Cr. Salt Cr. Buffalo PowderCr. River Porcupine Cr. T42N T42N 387 T41N

South Fork T41N Powder River R85W R84W R83W R82W R81W R80W R79W R78W R77W Antelope Cr. T40N T40N

T39N T39N CONVERSE COUNTY

T38N T38N Dry Cr. Dry Fork Cheyenne River T37N T37N 59

T36N T36N

Sage Cr. T35N T35N Legend Vegetation Community Sagebrush Shrublands R76W R75W R74W R73W R72W R71W R70W R69W Agricultural Saline Shrublands Aspen Short- and Mixed-Grass Prairie Barren Stabilized Dunelands Coniferous Forest Urban/Disturbed Deciduous Forest Water WYOMING Forested Riparian Wet Meadow Herbaceous Riparian Wetland/Fen Other Shrublands Vegetation Communities Vegetation Powder River Basin River Powder Coal Review Coal Figure 2.3-1

0 5 10 15 Miles

0 5 10 15 Kilometers Source: USGS 2010.

11/14/2012 AECOM 2.3-4

Table 2.3-2 Existing Cumulative Vegetation Disturbance by Subwatershed

1 Vegetation Type (acres)

grass grass

and

- -

2 Short Coniferous Forest Deciduous Forest Aspen Stabilized Dunelands Agricultural Urban/ Disturbed Barren Forested Riparian Herbaceous Riparian Meadow Wet Wetland/ Fen Water Subwatersheds Mixed Prairie Sagebrush Shrublands Saline Shrubland Other Shrublands Total

Antelope Creek 5,510 12,263 95 1 22 0 0 0 182 9,463 1,989 346 142 0 209 58 30,282

Clear Creek 1,444 1,341 40 2 24 0 2 0 426 254 27 103 135 0 1 2,785 6,582

Crazy Woman Creek 892 1,134 27 5 3 0 0 0 98 16 31 12 41 0 0 39 2,298

Dry Fork Cheyenne 1,006 1,484 146 0 0 0 0 1 106 108 106 81 30 0 5 13 3,088

Lightning Creek 1,099 1,903 100 0 0 0 0 0 206 416 16 55 38 0 15 2 3,850

Little Bighorn River 55 4 1 0 0 0 0 0 29 4 0 12 0 0 2 0 107

Little Missouri River 137 96 0 0 1 0 0 0 31 0 0 4 2 0 2 1 275

Little Powder River 9,831 7,685 66 2 173 0 0 0 703 5,532 87 373 356 0 133 51 24,993

Middle Fork Powder River 197 713 20 15 4 0 0 0 20 4 57 3 5 0 7 1 1,045

Middle North Platte River 285 403 23 0 0 0 0 63 3 5 29 4 10 0 2 827

Middle Powder River 2,427 2,986 12 0 309 0 0 0 350 0 81 168 45 0 21 1 6,399

North Fork Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Salt Creek 133 567 27 0 12 0 0 0 1 6 51 7 3 0 2 0 809

South Fork Powder River 49 429 12 1 53 0 0 0 2 42 49 0 1 0 2 12 653

Upper Belle Fourche River 13,563 21,646 104 2 42 0 0 0 1,574 16,726 356 1,028 245 0 523 405 56,214

Upper Cheyenne River 4,795 6,107 5 29 8 0 0 0 436 13,566 535 62 6 0 587 161 26,295

Upper Powder River 10,114 28,700 80 0 201 0 0 0 1,016 688 1,339 499 582 0 36 4 43,259

Upper Tongue River 6,327 1,871 71 22 107 1 2 0 1,198 494 88 93 353 0 36 9 10,671 2 Total 57,863 89,331 830 79 958 1 4 64 6,380 47,323 4,843 2,852 1,994 0 1,583 3,543 217,647

1 Based on GIS analysis of existing development-related disturbance as of the end of base year 2008 (inclusive of coal mine-related disturbance). 2 Slight differences in totals may occur due to rounding. Source: USGS 2010.

Task 1D Report December 2012 AECOM 2.3-5

Table 2.3-3 Existing Vegetation Disturbance from Coal Mine-related Development by Subwatershed

1 Vegetation Type (acres)

grass grass

and

- -

2 Coniferous Coniferous Forest Deciduous Forest Aspen Stabilized Dunelands Agricultural Urban/ Disturbed Barren Forested Riparian Herbaceous Riparian Meadow Wet Wetland/ Fen Water Short Prairie Sagebrush Shrublands Saline Shrubland Other Shrublands Subwatersheds Mixed Total

Antelope Creek 1,307 3,672 9 0 0 0 0 0 160 9,028 1,827 55 60 0 146 31 16,295

Clear Creek 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Crazy Woman Creek 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Dry Fork Cheyenne 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Lightning Creek 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Little Bighorn River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Little Missouri River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Little Powder River 655 1,663 0 2 4 0 0 0 158 5,181 9 102 19 0 34 47 7,874

Middle Fork Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Middle North Platte River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Middle Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

North Fork Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Salt Creek 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

South Fork Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Upper Belle Fourche River 2,286 3,542 0 2 10 0 0 0 539 14,214 260 114 73 0 266 395 21,702

Upper Cheyenne River 2,893 3,570 2 29 0 0 0 0 374 13,333 471 22 0 0 517 160 21,371

Upper Powder River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Upper Tongue River 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Total 7,140 12,447 11 33 15 0 0 0 1,231 41,756 2,568 293 151 0 963 633 67,242

1 Based on GIS analysis of existing development-related disturbance as of the end of base year 2008. 2 Slight differences in totals may occur due to rounding.

Source: USGS 2010.

Task 1D Report December 2012 AECOM 2.3-6 cactus (Opuntia spp.), and scarlet globemallow (), Wyoming big sagebrush ( var. wyomingensis) is a common shrub of this grass community in the PRB (Knight 1994). Within the PRB study area, short- and mixed-grass prairie areas are most common along the eastern foothills of the Big Horn Mountains and sporadically occur throughout much of the northern and central portions of the Wyoming PRB study area.

Sagebrush Shrubland The sagebrush shrubland vegetation community accounted for approximately 53 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community includes a combination of sparse, moderately dense, and dense Wyoming big sagebrush crown closure with a variety of understory grasses and forbs. Sagebrush shrubland is widely distributed and occupies a large portion of the Wyoming PRB study area. Other plant species that typically occur in this vegetation type may include silver sagebrush (), western wheatgrass, junegrass (Koeleria macrantha), needle-and-thread grass, Sandberg bluegrass (Poa secunda), prickly pear cactus, scarlet globemallow, and rabbitbrush (Chrysothamnus spp.). Sagebrush shrublands occur throughout the Wyoming PRB study area, except in the Big Horn Mountains and associated foothills. Larger, more contiguous tracts of sagebrush occur in the northeastern, central, and eastern portions of the Wyoming PRB study area.

Saline Shrubland The saline shrubland vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community typically occurs in saline soils and as a mosaic of multiple communities, with open to moderately dense shrublands dominated or codominated by greasewood ( vermiculatus) or four-wing saltbrush (). Other shrubs that may be present in some occurrences include shadscale (Atriplex confertifolia), Gardner's saltbush (Atriplex gardneri), Wyoming big sagebrush, big sagebrush (Artemisia tridentata ssp. tridentate), silver sagebrush, longleaf wormwood (Artemisia longifolia), birdfoot sagebrush (Artemisia pedatifida), and bud sage (Picrothamnus desertorum), sometimes with a mix of other low shrubs such as winterfat (Krascheninnikovia lanata) or shortspine horsebrush (Tetradymia spinosa). Occurrences often are surrounded by mixed salt desert scrub or big sagebrush shrublands. The herbaceous layer may be present but scattered. Within the Wyoming PRB study area, saline shrublands are dispersed along floodplains, locations with seeps or perched water tables, and along shale badlands.

Other Shrubland The other shrubland vegetation type accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation type is composed of two distinct shrub-dominate plant communities: mountain mahogany shrubland and mixed foothill shrubland. The mountain mahogany shrubland community is the largest component of this vegetation type and has two species-dominated sub-classes. The first sub-class occurs primarily in the foothills of the Big Horn Mountains in southwestern Johnson County and is dominated by curl-leaf mountain mahogany (Cercocarpus ledifolius). The second sub-class occurs in the southern portion of the Wyoming PRB study area and is dominated by true mountain mahogany (Cercocarpus montanus). The two mountain mahogany shrubland sub-classes occur on poorly developed soils derived from sandstone, limestone, and shale (Knight 1994). Plant species found in the undergrowth of the mountain mahogany community include fringed sage (Artemisia frigida), sulfurflower buckwheat ( umbellatum), bluebunch wheatgrass (Elymus spicatum), and junegrass.

The mixed foothill shrubland component of the other shrubland vegetation type is intermingled among the mountain mahogany communities. This community is dominated by mountain big sagebrush (Artemisia tridentata var. vaseyana) interspersed with antelope bitterbrush (Purshia tridentata), serviceberry (Amelanchier alnifolia), skunkbush sumac (Rhus trilobata), common chokecherry (Prunus virginiana), and snowberry (Symphoricarpos spp.). Common forbs and grasses found in the mixed foothill shrubland may include lupine (Lupinus spp.), arrowleaf balsamroot (Balsamorhiza sagittata), hairy goldenaster (Heterotheca villosa), basin wildrye (Elymus cinereus), and junegrass.

Task 1D Report December 2012 AECOM 2.3-7

Coniferous Forest The coniferous forest vegetation community accounted for approximately 4 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community includes Engelmann spruce (Picea engelmannii), Douglas fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta var. latifolia), ponderosa pine (Pinus ponderosa), limber pine (Pinus flexilis), and juniper (Juniperus spp.). These species tend to form associations based on elevation, exposure, and soil moisture. Typically, these species are segregated according to elevation. Juniper and pine forests tend to be lower in elevation, while spruce and fir forests occur at higher elevations. This vegetation community occurs primarily along the western edge of the Wyoming PRB study area, where the upper-elevation conifer species are more common and occur, in the northeastern corner where the lower elevation species are more common.

Deciduous Forest The deciduous forest vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This community is dominated by bur oak (Quercus macrocarpa) and is found in upland areas in the northern portion of the Western . It often occurs as small to large patches on buttes, escarpments, and in foothill zones, usually on northerly-facing slopes. Other species, such as American basswood (Tilia americana), quaking aspen (Populus tremuloides), eastern redcedar (Juniperus virginiana), and ash (Fraxinus spp.), may be present. The herbaceous layer can vary from sparsely to moderately vegetated and is composed of prairie grasses or woodland sedges (Carex spp). Shrub-associates can include chokecherry (Prunus virginiana), beaked hazelnut (Corylus cornuta), Saskatoon serviceberry (Amelanchier alnifolia), or snowberry (Symphoricarpos spp). Historically, a higher cover of grass species occurred as these stands were more open due to more frequent fires. Few good examples of this community likely remain because of past timber harvesting and heavy grazing. Where it occurs at elevations above 3,000 feet, ponderosa pine (Pinus ponderosa) woodlands are likely adjacent. This vegetation community occurs primarily in the western portion of the Wyoming PRB study area at the base of the Big Horn Mountains on foothills and drainageways.

Aspen The aspen vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. Aspen communities typically occur in depressions, ravines, valley bottoms, or on the lee sides of ridges. Aspen seedlings are intolerant of drier conditions; therefore, this community distribution typically is dictated by the availability of soil moisture. The understory of the aspen vegetation community has greater productivity and species diversity than any other forested upland vegetation type in the Wyoming PRB study area (Mueggler 1985). Quaking aspen is the dominant species in the aspen vegetation community. Common plant species in aspen stands include common snowberry (Symphoricarpos albus), serviceberry, Woods’ rose (Rosa woodsii), western yarrow (Achillea millefolium var. lanulosa), wild geranium (Geranium spp.), mountain brome (Bromus marginatus), and elk sedge (Carex geyeri). Many stands of aspen are a seral (i.e., transitional) community that would have conifers of various ages growing within them. In the Wyoming PRB, this vegetation type is limited to the Big Horn Mountains.

Stabilized Dunelands The stabilized dunelands vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. Stabilized dunes typically occur in basins, valleys, and plains. This community is composed of a mosaic of migrating, bare dunes; anchored dunes with sparse to moderately dense vegetation (less than 10 to 30 percent canopy cover); and stabilized dunes. Stabilized duneland is defined by the presence of migrating dunes or, where the dunes are entirely anchored or stabilized, evidence that the substrate is eolian and not residual, the vegetation is early- or mid-seral, and the substrate is likely to become actively migrating again with disturbance or increased aridity. Substrates are usually eolian sand, but small dunes composed of silt and clay downwind from playas in the Wyoming Basins (which usually support greasewood vegetation) also are included.

Task 1D Report December 2012 AECOM 2.3-8

Species occupying these environments often are adapted to shifting, coarse-textured substrates (usually quartz sand) and form patchy or open grasslands, shrublands or steppes, and occasionally woodlands. Vegetation varies and may be composed of Indian ricegrass (Achnatherum hymenoides), sand sagebrush (Artemisia filifolia), big sagebrush, four-wing saltbrush, Mormon tea (Ephedra spp.), yellow rabbitbrush (Chrysothamnus viscidiflorus), blackbrush (Coleogyne ramosissima), rubber rabbitbrush (), needle-and thread-grass, yellow wildrye (Leymus flavescens), sandhill muhly (Muhlenbergia pungens), lemon scurfpea (Psoralidium lanceolatum), antelope bitterbrush, blowout grass (Redfieldia flexuosa), alkali sacaton (Sporobolus airoides), greasewood, fourpart horsebrush, or Coldenia (Tiquilia spp.). Herbaceous species such as Indian ricegrass, blowout grass, and lemon scurfpea are characteristic of early-seral vegetation through much of this community’s range. Shrubs are commonly dominant on mid- to late-seral stands, and rubber rabbitbrush can be found at any stage. This vegetation community occurs in the southwestern portion of the Wyoming PRB study area within Converse County and in small patchy areas throughout the study area.

Agricultural The agricultural vegetation type accounted for approximately 4 percent of the vegetation cover in the Wyoming PRB study area. This land cover type is defined as croplands, pasture, or hay fields that have been plowed or planted. These areas also may include wooded or shrubby draws and riparian areas. Agricultural areas are most common along the eastern edge of the Big Horn Mountains, along the major drainages, and near Wright and Gillette.

Urban/Disturbed The urban/disturbed category accounted for approximately 2 percent of the surface area in the Wyoming PRB study area. This category includes lands covered by homes, businesses, streets, and a portion of the unvegetated surface mining areas. It is most common around cities and towns and along the eastern edge of the Wyoming PRB study area where many coal mines are located. A detailed description of the areas disturbed by surface mining is included below in the Existing Disturbance subsection.

Barren The barren category accounted for approximately 2 percent of the surface area in the Wyoming PRB study area. This cover type includes rock outcrops, roads, sandbars, eroded gullies, and areas with less than 10 percent ground cover and perennial snow and ice areas, as defined by the NWReGAP. It occurs as small, scattered areas throughout the Wyoming PRB study area, and as several large blocks in the southwestern portion of the study area.

Open Water The water category accounted for less than 1 percent of the surface area in the Wyoming PRB study area. This category includes lakes, ponds, streams, and open water in wetlands, as defined by the NWReGAP, and is scattered throughout the Wyoming PRB study area.

Existing Disturbance Because of past and present human activities in the Wyoming PRB study area, substantial areas of vegetation have been altered from their natural condition. The primary sources of surface disturbance to vegetation have resulted from: oil and gas activities and related development (e.g., major transportation pipelines); coal mining and related development (e.g., power , railroads); other mining (i.e., uranium, sand, gravel, scoria, bentonite, and leonardite [a low rank coal]); ranching; agriculture; road construction; and rural and urban housing and business development. Some of these alterations are included in the previous discussion of vegetation types, particularly in the agriculture, urban/disturbed, and barren land cover types. The total cumulative disturbance acreages as of the end of base year 2008 for each vegetation type by subwatershed (Table 2.3-2) have been estimated based on the past and present development activities defined in the Task 2 Report (AECOM 2011b). Coal mine-related vegetation disturbance for each vegetation type by subwatershed is presented in Table 2.3-3.

Task 1D Report December 2012 AECOM 2.3-9

Based on GIS analysis, as of the end of base year 2008, the existing development-related disturbance to vegetation communities (less barren, urban/disturbed, water, riparian, wet meadow, and wetland vegetation) in the Wyoming PRB study area was 155,509 acres, of which 20,877 acres of disturbance was related to coal mining (see Tables 2.3-2 and 2.3 3, respectively). (See Section 2.3.3.2, Riparian and Wetland Vegetation, relative to riparian/wetland vegetation impacts.) The primary vegetation communities impacted as a result of coal mine development have included sagebrush shrublands and short- and mixed-grass prairie. As of the end of base year 2008, approximately 39 percent of previously disturbed vegetation had been permanently reclaimed. Specific to the coal mines, approximately 32 percent of the vegetation disturbance had been permanently reclaimed (AECOM 2011b). It is assumed that the species composition on the reclaimed land is different than surrounding undisturbed lands, particularly in regard to the percent of woody shrub species during the early years following reclamation. Reclaimed mine land is defined by the WDEQ as affected land that has been backfilled, graded, topsoil reapplied, and permanently seeded according to approved practices specified in the reclamation plan (Christensen 2002).

The figures showing vegetation (Figure 2.3-1) and land use (Figure 2.6-2) depict differing distribution of agricultural land within the Wyoming PRB study area. The extent of agricultural land in these two figures varies because of the different sources used to derive the data. The figure for vegetation was derived from NWReGAP data. BLM land use mapping data was the source for the land use figure.

Other human disturbances to native vegetation typically are smaller in scale and are difficult to quantify in terms of affected acres. One such form of disturbance is damage to vegetation caused by fugitive dust that settles on plants primarily along the periphery of gravel roads. The source of the fugitive dust is primarily passing vehicles, with wind-blown dust generated from previously disturbed areas (e.g., road corridors or over-grazed land) also contributing. Fire suppression is another human induced alteration of native vegetation. By suppressing wildland fires, humans have caused shifts in the vegetation types that are present in the Wyoming PRB study area. Grazing presents another form of widespread disturbance within the Wyoming PRB study area, although no solid quantification of impacts to native vegetation can be ascertained. Finally, impacts due to species such as grasshoppers, Mormon crickets, and prairie dogs similarly are difficult to quantify. Disturbance to native vegetation that results from the above factors is not included in the analysis of the Wyoming PRB study area vegetation types.

2.3.3.2 Riparian and Wetland Vegetation Wetland and riparian areas are highly important water-related features in the arid landscape of northeastern Wyoming. Wetland and riparian areas occur throughout the Wyoming PRB study area in all 18 subwatersheds and typically are restricted to the lands immediately surrounding major and minor rivers, streams, creeks, draws, topographical depressions, lakes, and ponds. Many plant and wildlife species are found in no other habitat types (e.g., certain plant and bird species, amphibians, and turtles), while other wildlife species such as shorebirds, waterfowl, and weasels frequent these habitat types. These small, but important, ecosystems represent a vegetation structure, soil, and hydrology that is unique relative to the vast expanses of sagebrush and prairie grass that dominate the landscape of the region.

Four riparian and wetland vegetation types have been identified in the Wyoming PRB study area, including forested riparian, herbaceous riparian, wet meadow, and wetland/fen. These riparian vegetation types are described below. The acres of occurrence of pre-disturbance riparian and wetland vegetation types within the Wyoming PRB study area are presented by subwatershed in Table 2.3-1.

Forested Riparian The forested riparian vegetation community accounted for approximately 2 percent of the pre-disturbance vegetation in the Wyoming PRB study area. Areas covered by forested riparian vegetation are more common along some drainages today than in pre-settlement times due to the reduced frequency of tree-damaging floods as a result of reservoir construction and lateral drainage from irrigated uplands (Knight 1994). Forested riparian areas may be shrinking in other locations, particularly

Task 1D Report December 2012 AECOM 2.3-10 where cottonwoods are dominant, because of low cottonwood regeneration rates. This vegetation community is characterized by a variety of deciduous and coniferous tree species that occur along riparian areas. Coniferous forested riparian areas are rare, occurring only in the foothills of the Big Horn Mountains along the western edge of the Wyoming PRB study area. Deciduous forested riparian areas are much more common and occur throughout the Wyoming PRB study area. Some common species include plains cottonwood (Populus deltoides), narrow-leaf cottonwood (Populus angustifolia), quaking aspen, boxelder (Acer negundo), green ash (Fraxinus pennsylvanica), Russian olive (Elaeagnus angustifolia), and willow (Salix spp).

Herbaceous Riparian The herbaceous riparian vegetation community accounted for approximately 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community consists of a variety of riparian moist grasses, sedges, and rushes and may include woolly sedge (Carex lanuginosa), common spike rush (Eleocharis palustris), foxtail barley (Hordeum jubatum), wild licorice (Glycyrrhiza lepidota), and Canada goldenrod (Solidago canadensis). Herbaceous riparian vegetation is similar to the wet meadow vegetation type and often occurs in similar environments. Herbaceous riparian communities occur throughout the Wyoming PRB study area, with most occurrences associated with streams, rivers, and other aquatic habitats.

Wet Meadow The wet meadow vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. This vegetation community is dominated by herbaceous species found on wetter sites with very low-velocity surface and subsurface flows as defined by NWReGAP. Wet meadow is a grassland vegetation community that typically occurs on fine textured soils in valley bottoms where the water table is high enough to saturate the soil during a portion of the growing season. In addition, this vegetation community commonly occurs where springs emerge, along reservoirs, and in irrigated pastures (Knight 1994). Soils of this system may be mineral or organic. In either case, soils show typical hydric soil characteristics, including high organic content and/or low chroma and redoximorphic features. This system often occurs as a mosaic of several plant associations, often dominated by graminoids, including slimstem reedgrass (Calamagrostis stricta), white marsh marigold (Caltha leptosepala), heartleaf bittercress (Cardamine cordifolia), sheep sedge (Carex illota), smallwind sedge (Carex microptera), black alpine sedge (Carex nigricans), mountain sedge (Carex scopulorum), Bering’s tufted hairgrass, (Deschampsia caespitosa), fewflower spikerush (Eleocharis quinqueflora), Drummond’s rush (Juncus drummondii), arrowleaf ragwort (Senecio triangularis), Parry’s clover (Trifolium parryi), and American globeflower (Trollius laxus). Within the Wyoming PRB study area, wet meadow habitats that are widely distributed tend to exist as island habitats surrounded by dominant plant communities such as grasslands or shrublands. Wet meadows are more common in the northern and western portions of the Wyoming PRB study area than in the southern and eastern portions.

Wetland/Fen The wetland/fen vegetation community accounted for less than 1 percent of the pre-disturbance vegetation in the Wyoming PRB study area. The fen community occurs infrequently throughout the Rocky Mountains. It is confined to specific environments defined by groundwater discharge, soil chemistry, and peat accumulation of at least 1.3 feet. This system includes extreme rich fens and iron fens, both being quite rare. Fens form at low points in the landscape or near slopes where groundwater intercepts the soil surface. Groundwater inflows maintain a fairly constant water level year-round, with water at or near the surface most of the time. Constant high water levels lead to accumulation of organic material. In addition to peat accumulation and perennially saturated soils, the fens have distinct soil and water chemistry, with high levels of one or more minerals, such as calcium, magnesium, or iron. These fens usually occur as a mosaic of several plant associations dominated by water sedge (Carex aquatilis), mud sedge (Carex limosa), wollyfruit sedge (Carex lasiocarpa), dwarf birch (Betula nana), Bellardi bog sedge (Kobresia myosuroides), simple bog sedge (Kobresia simpliciuscula), Rolland’s bulrush (Trichophorum pumilum), and dwarf bulrush (Scirpus pumilus). Peatmoss (Sphagnum spp.) is indicative

Task 1D Report December 2012 AECOM 2.3-11 of iron fens. The surrounding landscape may be ringed with other wetland systems (e.g., riparian shrublands) or a variety of upland systems from grasslands to forests. These systems are isolated to the lower foothills along the eastern edge of the Big Horn Mountains along the western edge of the Wyoming PRB study area.

Closed depression wetlands occur more frequently than fens. This community is typified by upland depressional basins with an impermeable layer such as dense clay and hydric soils. These wetlands generally depend on precipitation and local runoff for replenishment. They can be saline, causing both the shallow lakes and depressions and the surrounding areas to be more brackish. Species richness varies considerably. Common spikerush (Eleocharis spp.), foxtail barley (Hordeum jubatum), along with golden tickweek (Coreopsis tinctoria), eastern annual saltmarsh aster (Symphyotrichum subulatum), and Pennsylvania smartweed (Polygonum pensylvanicum) are found in wetter and deeper depressions. Shallower depressions in rangelands commonly contain western wheatgrass (Pascopyrum smithii) and buffalograss (Buchloe dactyloides). Species that typify the saline closed depression wetlands are salt-tolerant and halophytic species, such as saltgrass (), alkali sacaton (Sporobolus airoides), and foxtail barley. During exceptionally wet years, an increase in precipitation can dilute the salt concentration in the soils of some of these wetlands, which may allow for the occurrence of less salt-tolerant species. Communities found within this wetland type also may occur in floodplains (i.e., more open depressions); however, these should not be considered a separate community unless they transition to areas outside the immediate floodplain. These communities are small and scattered throughout the Wyoming PRB study area within potholes, around seeps and springs, and along perennial streams and rivers.

The extent and distribution of these four wetland/riparian vegetation types is shown in Figure 2.3-1. However, many of the riparian areas in the Wyoming PRB study area are too small to be plotted on a map of this scale, including the riparian corridors of nearly all of the major rivers and streams. Just over 3 percent of the Wyoming PRB study area consists of riparian and wetland vegetation. Approximately 18 percent (45,335 acres) of the almost 246,318 acres of riparian areas and wetlands in the Wyoming PRB study area is contained in the Upper Powder River subwatershed. The dominant type of riparian area and wetland is the forested riparian that constitutes approximately 50 percent (approximately 122,657 acres) of all riparian areas and wetlands within the Wyoming PRB study area. The Upper Belle Fourche River subwatershed has the greatest extent (23,096 acres) of the forested riparian ecosystem, the Upper Powder River subwatershed has the greatest extent (19,723 acres) of the herbaceous riparian ecosystem, the Middle Fork Powder River subwatershed has the greatest extent (70 acres) of the wet meadow wetland type, and the Little Powder River subwatershed has the greatest extent (6,018 acres) of the wetland/fen ecosystem.

Riparian and Wetland Ecosystem Functions Riparian and wetland ecosystems have various functions that occur at the landscape scale, including: 1) flood storage and flood-peak desynchronization; 2) recharge to the groundwater aquifer; 3) flood-flow attenuation; 4) purification of water via removal of nutrients and toxic compounds; and 5) recreation (Carter 1986; Zinn and Copeland 2001). These functions apply to all riparian zones of the subwatersheds within the Wyoming PRB study area. Evaporation rates in much of Wyoming, including the PRB study area, greatly exceed precipitation rates, and the gentle slopes or relatively flat valleys of many of the 18 subwatersheds contribute to generally low-flow, highly sinuous rivers and streams spaced widely apart that have very narrow and limited riparian corridors.

The ecological community-scale functions of riparian ecosystems include: 1) the presence of surface water and abundant soil moisture that attracts or facilitates plant and animal occurrence; 2) high productivity within various food chains; 3) disproportionate species richness and abundance relative to surrounding areas; 4) diversity and interspersion of habitat features that create more niches for plants and animals; and 5) corridors for animal dispersion and migration (Brinson et al. 1981). The functions of riparian and wetland ecosystems at the ecological community scale ultimately depend on the hydrology of the watershed. The rates of sedimentation and nutrient deposition, as well as the energy of water flow

Task 1D Report December 2012 AECOM 2.3-12 and local soil types, affect the vegetation community that establishes itself and thrives in the riparian zone. Other factors that influence the riparian vegetation include elevation and moisture gradients, floodplain width, and shallow groundwater depth. These components also influence the wildlife communities that are attracted to, and use, the riparian zone.

Hunters, anglers, bird watchers, and biologists have long recognized the value of riparian ecosystems to fish and wildlife. Riparian ecosystems are particularly valuable in a dry environment such as Wyoming. It has been estimated that, although only 1 percent or less of the region is classified as riparian land, approximately 80 percent of the native animals depend on riparian zones for food, water, shelter, and migration routes during some time of the year (Olson and Gerhart 1982). Riparian ecosystems are known for high animal species richness relative to other ecosystem types.

Existing Wetland and Riparian Impacts Alteration of hydrologic conditions can affect the physical and chemical properties in a wetland, such as pH, soil salinity, sediment properties, oxygen content, and nutrient availability. These wetland properties affect the biota in terms of establishment, recruitment, maintenance, and spatial arrangement. Small changes in the hydrologic conditions can result in massive responses by wetland biota in terms of species composition, species richness, and ecosystem productivity (Mitsch and Gosselink 1993). Peak flows, periodic flooding, and related stream channel processes, such as meandering, are closely related to the reproduction and growth of riparian plant species (Busch and Scott 1995). The maintenance of cottonwood and willow populations in riparian ecosystems depends on ground availability of water that, in turn, depends on instream flows (Busch et al. 1992). Changes to the interrelationships among surface water dynamics, groundwater level, and river channel processes can lead to changes in the establishment and maintenance of dependent riparian plant communities (Busch and Scott 1995).

The primary existing impacts to the riparian ecosystems of the Wyoming PRB study area (e.g., livestock grazing and agricultural water withdrawals) are similar to riparian ecosystems throughout the West. Riparian vegetation and the availability of water in an otherwise dry landscape tend to attract livestock. Livestock spend more time grazing in riparian ecosystems than in adjacent uplands. Grazing along primarily low-order streams can cause increased erosion and sedimentation, decreased water quality via introduction of pathogens and excess nutrients, and channel downcutting (Brinson et al. 1981; Kauffman and Kreuger 1984). Grazing removes plants through consumption and trampling, particularly young plants, thereby affecting the age structure and reproduction of the plant population. Species composition of the riparian ecosystem also may be altered (Brinson et al. 1981). As a result of these impacts, the functions of the riparian and wetland ecosystems may be diminished or disappear altogether. The potential indirect effects that would follow include increased flows, diminished flood storage capacity, increased frequency of flooding, increased upland erosion and sedimentation, decreased water quality, increased water temperature, and decreased aquatic biota species diversity. Details regarding the current condition of riparian ecosystems on specific rivers within the Wyoming PRB study area are not available.

Agricultural uses have, in many cases, diminished the minimum instream flows necessary to sustain aquatic life and the riparian ecosystem for numerous streams and rivers in the arid Rocky Mountain states (Mitsch and Gosselink 1993). Water withdrawal reduces the availability of water for the maintenance of riparian ecosystems and, in extreme cases, can alter the composition of the plant community to include more upland species or eliminate the riparian or wetland ecosystem. Water diversions and withdrawals also can upset the salt balance by minimizing the flood frequency that usually leaches soil salts within the floodplain (Brinson et al. 1981). Additionally, return flows from irrigated fields in the arid West often contain high levels of inorganic salts, selenium, and other metals that may negatively affect water quality in the rivers or streams. Downstream uses (e.g., municipal and livestock water supply and aquatic habitat) may be adversely affected by excessive amounts of salts and metals that currently are being introduced by the return flows from irrigated fields. The existing water quality parameters (e.g., concentrations of metals such as selenium, SAR, salinity, and total dissolved solids [TDS]) are discussed in the Task 1B Report for the PRB Coal Review, Water Resources

Task 1D Report December 2012 AECOM 2.3-13

(AECOM 2012 [in progress]). Approximately 86 percent of surface water withdrawals from the rivers and streams in the two state water planning basins that encompass the Wyoming PRB study area are for irrigation. The majority of this consumption (approximately 73 percent) occurs in the Powder/Tongue River Basin Planning Area, which encompasses the western and northeastern portions of the study area. Within each of the planning areas, approximately 91 percent of the surface water consumption in the Powder/Tongue River Basin Planning Area is for irrigation, and approximately 75 percent of the surface water withdrawal is used for irrigation in the Northwest Wyoming River Basins Planning Area (HKM Engineering et al. 2002a,b; WWC Engineering et al. 2007).

Based on GIS analysis, as of the end of base year 2008, the existing development-related disturbance to wetland, wet meadow, and riparian areas in the study area was 6,429 acres, of which 1,407 acres of disturbance was related to coal mining activity (Tables 2.3-2 and 2.3-3, respectively). The primary wetland/riparian communities impacted as a result of coal mine development have included wetland/fen communities.

In the Wyoming PRB study area, CBNG-produced water currently is disposed of via discharge to: 1) upland impoundments, including headwater reservoirs with mandates for containment of all effluent and unlined off-channel impoundments; 2) unlined on-channel impoundments; 3) ephemeral drainages; 4) topographically and hydrologically isolated playa lakes; and 5) deep well injection. In 2008, discharge to on-channel impoundments/ephemeral drainages was the primary disposal method in all the subwatersheds except Clear Creek and Upper Cheyenne River. In the Clear Creek subwatershed, the primary disposal method was via discharge to upland impoundments; there was no discharge to on-channel impoundments/ephemeral drainages in this subwatershed. In the Upper Cheyenne River subwatershed, approximately 57 percent of the CBNG-produced water was discharged to playa lakes (AECOM 2011b). In 2009, almost 5,000 CBNG impoundments existed in the Wyoming PRB study area (AECOM 2011a).

The water quality of CBNG-produced water varies with location and depth in the basin. CBNG-produced water in the northwestern portion of the Wyoming PRB typically is high in sodium bicarbonate, has TDS values well over 1,000 milligram per liter, and has a SAR greater than 8, making the water unsuitable for some agricultural uses (AECOM 2012 [in progress]). SARs of 13 or more can cause irreversible changes to soil structure that cause reduced percolation of rainfall and surface water flows, restrict root growth, limit permeability of gases and moisture, and cause difficult tillage (Seelig 2000; U.S. Salinity Laboratory Staff 1954). For permitted discharge to ephemeral drainages, the operator must comply with permitted effluent limits stipulated by the WDEQ. Direct discharge to drainages in the Powder River and Tongue River drainages typically is treated for SAR and/or EC to ensure compliance (WDEQ 2010). In the eastern portion of the basin, CBNG-produced water generally is low in TDS and sodium and often of better quality than the surface water (AECOM 2012 [in progress]). Based on current discharge methods, the quality of CBNG-produced water in the eastern portion of the basin, treatment of waters (as needed) to meet compliance, and WDEQ permit requirements for discharge to ephemeral drainages, potential water quality impacts to riparian and wetland vegetation associated with on-channel impoundments and ephemeral drainages are anticipated to be minimal. WDEQ regulations prohibit development of impoundments above Class I and Class II groundwater, thus limiting the impoundments to areas where the shallow groundwater is not used for municipal or domestic consumption. The WOGCC has siting guidelines and permitting requirements for off-channel CBNG impoundments on fee or state leases. Discharges to upland impoundments potentially may affect associated wetland communities depending on the location in the basin and the species present.

Conveyance loss of CBNG water discharged to ephemeral drainages depends on the time of year, the presence and number of on-channel impoundments, the amount of vegetation within and along the channel, and the permeability of the alluvium and (in the Wyoming PRB) the upper Wasatch Formation. Most CBNG discharge water in the Wyoming PRB infiltrates, evaporates, or is lost through evapotranspiration. Impacts to surface water flow are thus limited to within a few miles of the discharge outfall (AECOM 2012 [in progress]). It is not known how much of the CBNG discharge water reaches specific streams and wetlands within the subwatersheds of the Wyoming PRB study area. Some stream

Task 1D Report December 2012 AECOM 2.3-14 segments, including ephemeral and often dry segments, receive CBNG-produced water over a large portion of a year. It can be assumed that existing riparian areas that received continuous input of produced water were affected through abnormal inundation, overly saturated soils, increased flow velocity and subsequent erosion, impediment of seedling recruitment, and other factors. Conversely, CBNG water discharged to previously unvegetated channel segments may result in temporary development of riparian or wetland communities for the duration of the discharge in a given location. Based on the conveyance loss of discharged CBNG water, these effects would be limited to areas within a few miles of the discharge outfalls. It is assumed that discharge to upland impoundments either would sustain or potentially create associated riparian/wetland areas, depending on whether the discharge is to an existing or new impoundment.

2.3.3.3 Invasive and Non-native Species Once established, invasive and non-native plant species can outcompete and eventually replace native species, thereby reducing forage productivity and the overall vigor of existing native plant communities. The State of Wyoming has designated 25 plant species as noxious weeds. These species are listed in Table 2.3-4.

Table 2.3-4 State of Wyoming Designated Noxious Weeds

Common Name Scientific Name Quackgrass Agropyron repens Common burdock Arctium minus Hoary cress (whitetop) Cardaria draba/Cardaria pubescens Plumeless thistle Carduus acanthoides Musk thistle Carduus nutans Diffuse knapweed Centaurea diffusa Spotted knapweed Centaurea maculosa Russian knapweed Centaurea repens Ox-eye daisy Chrysanthemum leucanthemum Canada thistle Cirsium arvense Field bindweed Convolvulus arvensis Houndstongue Cynoglossum officinale Russian olive Elaeagnus angustifolia Leafy spurge Euphorbia esula Skeletonleaf bursage Franseria discolor Common St. Johnswort Hypericum perforatum Dyers woad Isatis tinctoria Perennial pepperweed (giant whitetop) Lepidium latifolium Dalmatian toadflax Linaria dalmatica Yellow toadflax Linaria vulgaris Purple loosestrife Lythrum salicaria Scotch thistle Onopordum acanthium Perennial sowthistle Sonchus arvensis Saltcedar Tamarix spp. Common tansy Tanacetum vulgare

Task 1D Report December 2012 AECOM 2.3-15

Wyoming is experiencing rapid introduction and spread of noxious and invasive weeds on all lands throughout the state, regardless of surface ownership. The potential for noxious and invasive weeds to continue spreading to new areas, particularly areas of disturbance, is high. As a collaborative effort, the BLM, South Goshen Cooperative Extension Conservation District, Wyoming Department of Agriculture, NRCS, and 42 private surface owners joined Wyoming Game and Fish Department (WGFD) and Weed and Pest District officials in efforts to control the spread of noxious weeds. This group agreed to a long-term integrated weed management plan, public awareness and prevention programs, and a common inventory, while monitoring and reporting on their progress.

Noxious weeds occur throughout the Wyoming PRB study area. Their occurrence, distribution, and density are variable and influenced by many factors, including disturbance type and frequency, climatic conditions, soil conditions, and local management efforts. Noxious weed lists are maintained by the Wyoming Weed and Pest Council (WWPC) and by county weed and pest districts. Data relative to known occurrences of noxious weeds or species of concern were obtained from the WWPC website and the University of Invaders database system (Table 2.3-5).

Table 2.3-5 Known Occurrences of Noxious and Invasive Species of Concern

Campbell Converse Johnson Sheridan Species County County County County Absinth wormwood Buffalobur X X X X Bull thistle X X X Canada thistle X X X X Cheatgrass X X X X Common burdock X X X X Common cocklebur X X X X Common lambsquarters X X X X Common mullein X X X X Common sunflower X X X X Common St. Johnswort Common tansy X X Curlycup gumweed X X X X Dalmation toadflax X X X X Diffuse knapweed X X X Dyer’s woad Field bindweed X X X X Halogeton X X X Houndstongue X X X X Kochia X X X X Leafy spurge X X X X Milkweed X X Musk thistle X X X X

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Table 2.3-5 Known Occurrences of Noxious and Invasive Species of Concern

Campbell Converse Johnson Sheridan Species County County County County Ox-eye daisy X X Perennial pepperweed X Perennial sowthistle X X X X Pigweed X X X X Plains larkspur X X Platte thistle X X Plumeless thistle Pricklypear cactus X X X X Puncturevine X Purple loosestrife Ragweed X X X X Russian knapweed X X X X Russian Olive X X X X Russian thistle X X X Salt cedar X X X X Sandbur X X NA NA Scotch thistle X X X X Skeletonleaf bursage X X Sulfur cinquefoil X X Spotted knapweed X X X X Sumpweed NA X X X Tarweed NA X NA NA Whitetop X X X X Wild licorice X X X X Wild oat X X X X Yellow bedstraw X Yellow toadflax X X X

Source: WWPC 2012. NA = Not available.

In addition to the state-designated list of noxious weeds, Campbell, Converse, Johnson, and Sheridan counties declared weeds of concern in the year 2012 under the authority of the Wyoming Weed and Pest Control Act. Table 2.3-6 provides a summary of county declared weeds of concern.

Task 1D Report December 2012 AECOM 2.3-17

Table 2.3-6 County Declared Weeds of Concern

Campbell Converse Johnson Sheridan Species County County County County Absinth wormwood X Baby’s breath X Black henbane X X Buffalobur X X X X Black henbane X X Bull thistle X Bur buttercup X Cheatgrass/downy brome X Chickory X Common cocklebur X X X X Common crupina X Common mullein X X X Common sunflower X Curly dock X X X Curlycup gumweed X Dames rocket X Goatsrue X Gorse X Halogeton X Iberian starthistle X Italian thistle X Jointed goatgrass X Meadow knapweed X Medusahead X Musk mustard X Orange hawkweed X Plains larkspur/Geyer X larkspur Poison hemlock X Puncturevine X X X Purple starthistle X Redstem filaree X Rush skeletonweed X Sandbur X Scentless chamomile X

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Table 2.3-6 County Declared Weeds of Concern

Campbell Converse Johnson Sheridan Species County County County County Scotch broom X Showy milkweed X X Squarrose knapweed X Sulfur cinquefoil X Syrian beancaper X Tall mountain larkspur X Tansy ragwort X Teasel X Wavyleaf thistle X Wild licorice X X Western sticktight X X Yellow hawkweed X Source: WWPC 2012.

The distribution and spread of many weeds of concern currently are being monitored by the University of Wyoming Cooperative Agricultural Pest Survey (CAPS) in association with county weed and pest districts and the Wyoming Department of Agriculture. Estimated acres of weed infestations by species/county are presented in Table 2.3-7. Some of the additional species being monitored that occur within the Wyoming PRB study area include: broom snakeweed (), common lambsquarters (Chenopodium album), common sunflower (), curlycup gumweed (), halogeton (Halogeton glomeratus), kochia (Kochia scoparia), milkweed (Asclepias spp.), pigweed (Amaranthus spp.), plains larkspur (Delphinium geyeri), platte thistle (Cirsium canescens), pricklypear cactus (Opuntia polyacantha), puncturevine (Tribulus terrestris), ragweed (Ambrosia spp.), Russian thistle (Salsola australis), sandbur (Cenchrus longispinus), sulfur cinquefoil (Potentilla recta), sumpweed (Iva xanthifolia), tarweed (Madia glomerata), wild oat (Avena fatua), and yellow bedstraw (Galium verum).

Although data relative to known occurrences of noxious weeds in the Wyoming PRB study area is scarce, the actual occurrence potential is assumed to be commensurate with the type and frequency of disturbance and the site-specific reclamation and weed control measures that currently are or would be implemented.

Table 2.3-7 Occurrence of Noxious Weeds and Weeds of Concern in Counties of the Wyoming PRB

Areal Extent of Infestation1 (acres) 101 to 1,001 to 5,001 to Species 0 1 to 100 1,000 5,000 20,000 >20,000 Absinth wormwood Ca, Co, J, S Baby’s breath Ca, S Co Black henbane Co, J, S Ca Buffalobur S Ca, Co J

Task 1D Report December 2012 AECOM 2.3-19

Table 2.3-7 Occurrence of Noxious Weeds and Weeds of Concern in Counties of the Wyoming PRB

Areal Extent of Infestation1 (acres) 101 to 1,001 to 5,001 to Species 0 1 to 100 1,000 5,000 20,000 >20,000 Bull thistle Ca, Co, J S Bur buttercup Ca Canada thistle Co Ca, S J Cheatgrass Ca, Co, J Common burdock Co Ca, J, S Dalmatian toadflax Co, S Ca, J Diffuse knapweed Ca, Co, S J Field bindweed Co Ca, J, S Foxtail barley Co Ca, S J Hoary cress Co, J, S Ca Houndstongue Ca, Co S J Jointed goatgrass J Co, S Ca Leafy spurge Co Ca J, S Musk thistle Ca, S Co, J Perennial S, Ca J Co pepperweed Purple loosestrife Ca, Co. J S Quackgrass Ca, Co, S J Rush skeletonweed Ca, Co, S, J Russian knapweed Co, S Ca, J Saltcedar Co Ca, S J Scotch thistle S, Ca Co J J Skeletonleaf bursage J, S Ca Spotted knapweed Ca, Co, J S Yellow toadflax Ca Co, J, S

1 Ca = Campbell County, Co = Converse County, J = Johnson County, S = Sheridan County.

Source: University of Wyoming 2010.

2.3.3.4 Special Status Species Special status species are those species for which state or federal agencies afford an additional level of protection by law, regulation, or policy. Included in this category are federally listed and federally proposed species that are protected under the Endangered Species Act (ESA), or are considered candidates for such listing by the U.S. Fish and Wildlife Service (USFWS), as well as BLM, FS, and WGFD sensitive species.

Task 1D Report December 2012 AECOM 2.3-20

In accordance with the ESA, as amended, land management agencies in coordination with the USFWS must ensure that any action that they authorize, fund, or carry out would not adversely affect a federally listed threatened or endangered species. In addition, as stated in Special Status Species Management Policy 6840 (6840 Policy) (Rel. 6-151), it also is BLM policy “to conserve listed species and the ecosystems on which they depend, and to ensure that actions requiring authorization or approval by the BLM are consistent with the conservation needs of special status species and do not contribute to the need to list any special status species, either under the provisions of the ESA or other provisions” identified in the 6840 Policy.

A total of 16 special status plant species were identified as potentially occurring within the Wyoming PRB study area, including two federally threatened species, six BLM sensitive species, and eight FS sensitive species. No WGFD sensitive species were identified in the Wyoming PRB study area. The identified threatened and endangered species, their associated habitats, and their potential for occurrence within the Wyoming PRB study area are summarized below. Occurrence potential was evaluated for each species based on its habitat requirements and/or known distribution. Table 2.3-8 lists the BLM and FS sensitive species and their associated habitats.

Ute Ladies’-tresses Orchid Ute ladies’-tresses orchid (Spiranthes diluvialis) currently is listed as federally threatened (USFWS 2012b). A petition to delist this species and initiate a 5-year review was issued by the USFWS in 2004 (69 Federal Register [FR] 60605-60607), and a rangewide status review was completed in 2005 (Fertig et al. 2005). The final ruling is pending. This species currently is known from western Nebraska, southeastern Wyoming, north-central Colorado, northeastern and southern Utah, east-central Idaho, southwestern Montana, and central Washington. In Wyoming, the Ute ladies’-tresses orchid is known from the western Great Plains in Converse, Goshen, Laramie, and Niobrara counties. Rangewide, the Ute ladies’-tresses orchid occurs primarily on moist, sub-irrigated or seasonally flooded soils in valley bottoms, gravel bars, old oxbows, or floodplains bordering springs, lakes, rivers, or perennial streams at elevations between 1,780 and 6,800 feet (Fertig 2000). Suitable soils vary from sandy or coarse, cobbley alluvium to calcareous, histic, or fine-textured clays and loams. Populations have been documented from alkaline sedge meadows, riverine floodplains, flooded alkaline meadows adjacent to ponderosa pine, Douglas fir woodlands, sagebrush steppe, and streamside floodplains. Some occurrences also are found on agricultural lands managed for winter or early season grazing or hay production. Known sites often have low vegetative cover and may be subjected to periodic disturbances such as flooding or grazing. Populations are often dynamic and “move” within a watershed as disturbances create new habitat or succession eliminates old habitat (Fertig and Beauvais 1999).

In Wyoming, this species is known from four occurrences, all discovered between 1993 and 1997 (Fertig et al. 2005). The only population known to occur within the Wyoming PRB study area is located in Converse County, along a tributary of Antelope Creek. The BLM Casper Field Office administers the land at this location. Based on Fertig et al. (2005), the number of individual plants observed in this population between 1994 and 2004 varied from 0 to 35. Current threats to this population include competition from non-native plants and vegetation succession. The three remaining Wyoming populations found outside of the PRB study area are located in Goshen, Niobrara, and Laramie counties on lands owned by the State of Wyoming and private parties. As reported by Fertig et al. (2005), populations overall are more stable, especially if subterranean seedling and dormant individuals are counted, and more tolerant of human-induced disturbances than originally suspected.

Task 1D Report December 2012 AECOM 2.3-21

Table 2.3-8 BLM and FS Sensitive Plant Species (2012)

Habitat Association2/ Common Name Scientific Name BLM1 FS1 Elevational Range Habitat Laramie columbine Aquilegia S -- RO Often found in shady crevices of laramiensis 6,250- 8,000 feet amsl north-facing granite boulders and on cliffs with pockets of rich soil. Limber pine Pinus flexilis L -- LIM Often found in open forests in the sub 4900-12,000 feet amsl alpine to alpine zones and in semi-arid areas on dry rocky ridges and windswept peaks. In Wyoming, it grows mainly on soils derived from limestone or sandstone and is notably absent on adjacent granitic substrates. Porter's sagebrush (Porter's Artemisia porteri D -- GL Occupies sparsely vegetated wormwood) 5,300- 6,500 feet amsl badlands of ashy or tufaceous mudstones and clay slopes. In the northern Wind River Basin, this species is found in semi-barren, low desert shrub communities on dry, whitish, ashy-clay hills, gravelly-clay flats, and shaley erosional gullies of the Wagon Bed Formation. Many-stemmed spiderflower Cleome multicaulis S -- GL Occupies whitish, alkali-rich, strongly (slender spiderflower) 5,860 feet amsl hydrogen-sulfide scented soils that border shallow, spring-fed playa lakes or dried lakebeds. Populations are most abundant on damp, but not flooded, flats bordering playa lakes. This species also may be present in lower numbers on clayey dunes surrounding alkaline lakes. Small patches also may occur in dry alkaline depressions.

Task 1D Report December 2012 AECOM 2.3-22

Table 2.3-8 BLM and FS Sensitive Plant Species (2012)

Habitat Association2/ Common Name Scientific Name BLM1 FS1 Elevational Range Habitat Williams’ wafer-parsnip Cymopterus S -- RO Occupies open, south or east-facing (Williams' spring parsley) williamsii 6,000-8,300 feet amsl ridge tops and upper slopes with exposed limestone outcrops or talus. Suitable soils tend to be thin, sandy, and often restricted to small cracks or pockets in limestone bedrock. Barren rock can provide up to 50 percent of the total cover. Laramie false-sagebrush Sphaeromeria V -- PJ, LIM, MS Occupies gentle slopes or rims of dry, (Laramie chickensage) simplex 7,200-8,760 feet amsl rocky limestone-sandstone "pebble plains" in wind-scoured openings. Barr’s milkvetch Astragalus barrii -- D GL, MS A cushion plant in badland islands in 3,700-5,700 feet amsl grassland matrix. Occupies eroded ridge tops, calcareous, zeolite, bentonite influenced soils, upper and midslope, more often on north and east aspects. Needs a pollinator. Iowa moonwort Botrychium -- S GL, MS Native species are found in unplowed campestre 3,700-5,000 and 10,800 with thatch or disturbance feet amsl (due to grazing), loess prairies, dunes; sandy soils along railroad tracks, calcareous soils underlain by: limestone, Pierre Shale, Laramie Formation, and calcareous sedimentary rocks. This species is associated with little blue stem. Foxtail sedge Carex alopecoidea -- S RIP Wet meadows, streamside, Carex 5,600-5,900 feet amsl willow communities. Prairie dodder Cuscuta plattensis -- S GL, SS Annual, rootless, twining, parasitic 4,200-4,900 feet amsl herb found on sand prairie hills parasitizing Psoralea, Ambrosia, Grindelia, Solidago, and Helianthus spp.

Task 1D Report December 2012 AECOM 2.3-23

Table 2.3-8 BLM and FS Sensitive Plant Species (2012)

Habitat Association2/ Common Name Scientific Name BLM1 FS1 Elevational Range Habitat Elliptic spike rush Eleocharis elliptica -- S RIP Associated with thermal seeps/ 6,200 to 7,250 feet amsl springs and stock ponds. Visher's buckwheat (Dakota -- V GL, MS Occurs in badland islands in a buckwheat) 1,900-3,000 feet amsl grassland matrix; needs a pollinator. Common twinpod Physaria -- S GL, PP, WT Occurs in the PRB on sandstone didymocarpa var. 3,300-9,000 feet amsl outcrops, redbed clay (clinker or lanata scoria)-shale slopes, calcareous substrates, and road cuts on open, shrub-dominated slopes, sometimes in association with a sparse cover of ponderosa pine and Rocky Mountain juniper. American cranberrybush Viburnum opulus -- S RIP Occurs in wetlands, fens, marshes, (highbush cranberry) var. americanum 4,200-4,950 feet amsl moist woods, and thickets in association with paper birch. 1 S = Suspected; D = Documented; V = Vicinity. 2 = GL = Grassland; LIM = Limber pine; MS = Mountain shrub; PJ = Pinyon pine/juniper; PP = Ponderosa pine; RIP = Riparian; RO = Rock/cliff/cave/canyon/mines; WT = Woodland thicket. Sources: Anderson and Cariveau 2003; BLM 2012; Fertig 2000; Ormseth 2012; Steele 2012; USDA 2012; Wyoming Natural Diversity Database (WYNDD) 2012.

Task 1D Report December 2012 AECOM 2.3-24

Blowout Penstemon The blowout penstemon (Penstemon haydeni) is listed as federally endangered (USFWS 2012a). The plant’s current known range in Wyoming consists of the Ferris Dunes area in northwestern Carbon County, where the plant is restricted to two habitat types: steep, northwest facing slopes of active sand dunes with less than 5 percent vegetative cover; and north-facing sandy slopes on the lee side of active blowouts with 25 to 40 percent vegetative cover (USFWS 2012a). Blowouts are formed as strong winds deposit sands from the windward side of a dune to the leeward side and create a sparsely vegetated crater-like depression. Known populations in Wyoming are found between 6,680 and 7,440 feet amsl. This species also is suspected to occur on the Thunder Basin National Grasslands based on the occurrence of potentially suitable habitat (USFWS 2012a).

Task 1D Report December 2012