Characterization of Desert Wildlife Management
Areas (DWMAs) in Clark County Nevada

Tony Krzysik, Shipley Group
May 2005

Coyote Springs and Mormon Mesa Desert Wildlife Management Areas (DWMAs) and the Coyote Springs Investments Development Area (CSI)

This May Newsletter focuses on characterizing the diverse habitats and ecosystems of Coyote Springs and Mormon Mesa DWMAs, as well as the private parcel known as Coyote Springs Investments (CSI). Although CSI is private land, its land-use has profound implications for the conservation strategies in these two DWMAs and also in the Desert National Wildlife Range. The CSI parcel was originally transferred from BLM to Aerojet under congressional action for the purpose of building a remote rocket fuel manufacturing facility. Currently, the 42,788 private parcel is scheduled for a large-scale residential development with a number of golf courses. The contrast between the ecological effects of the two land-uses is incredible. Aerojet would have only a handful of commuting workers, reasonable water use, and containable pollution. A residential development of this size would have an enormous resident population with associated highway and infrastructure development. The associated major ecological impacts include: very poor landscape location; critical landscape fragmentation from the development itself, I93 and associated roads; extensive and broad reaching land-use of the surrounding ecosystems; wildlife mortality from roads, residents, and pets; extensive use of water resources; and a wide variety of pollution problems (land, water, air, noise). Even highly experienced and well-intentioned backcountry users can have high negative impacts on resident biota (Knight and Gutzwiller 1995). The CSI parcel sits directly on the Pahranagat Wash. This wash and its riparian biological community, along with the Meadow Valley Wash (13 miles to the east) represent the headwaters of the Muddy River. The Muddy, Virgin, and Colorado Rivers are the only perennial surface flows in the entire Mojave Desert in four states. These rivers and their associated riparian communities are responsible for the northeast Mojave Desert having the highest biodiversity in the entire desert (see Figure 5, February Newsletter, Shipley web site). The Amargosa River has only occasional segments of surface flow, and the Mojave River only flows after extensive precipitation, because of excessive drawdown in associated residential and agricultural communities. The SCI parcel, especially with the increased development and use of I93, essentially forms a biological barrier between Coyote Springs and Mormon Mesa DWMAs. The only landscape corridor for the desert tortoise between these two DWMAs is a narrow opening between the Meadow Valley Mountains and Arrow Canyon Range in the vicinity of C168. The presence of CSI and this highway represent a formidable barrier to desert tortoise gene exchange. Recall that it only takes a single genetic exchange per generation for populations to be panmictic (all individuals are potential recombination partners and are considered to have complete gene mixing). This corridor is shown in this Newsletter in Figures 25, 56, and 78; and in a large landscape context in Figures 20 and 21. The ecological effects of roads have been well-documented, but there is still a great deal that needs to be learned (e.g., Langton 1989, Sherwood et al. 2002, Forman et al. 2003).

Most citizens would surmise that the worst impact of the CSI development is the loss of almost 43,000 acres of landscape. Nothing could be further from the truth. Of far greater importance to the cumulative ecological footprint is its location in a relatively wilderness setting, associated fragmentation of much larger and biologically important landscapes, the large number of permanent residents, and severe impacts on important water resources. These factors could contribute to over 95 percent of the total ecological impact.

Coyote Springs DWMA

The Coyote Springs DWMA represents the highest habitat and ecological community diversity among the four DWMAs, primarily attributed to a large elevational gradient. High elevations have greater cloud cover, humidity, precipitation, and lower temperatures; and hence lower evaporation, plant transpiration rates, and higher soil moisture. Mountains in desert landscapes support different plant communities and have higher photosynthetic productivity than the arid basins beneath them. However, in the extreme elevations of alpine zones, community diversity and productivity dramatically drop. The Sheep Range with elevations up to 9912 feet is located within the original U.S. Fish and Wildlife Service proposed CS-DWMA (USFWS 1994). The elevation is 2400-2800 ft on the lower eastern slopes of the range. The development of plant communities with elevation in the Sheep Range is informative for conservation values, and is illustrative for other DWMAs, Clark County, and the northern Mojave Desert. The original CS-DWMA also includes the eastern and western bajadas of the Sheep Range, the eastern boundary is I93, and the western boundary is the large expanse of Nellis Air Force Range (NAFR) (which includes the Nevada Test Site). Therefore, this original DWMA is essentially the Desert National Wildlife Range (DNWR), and in combination with NAFR represents a major regional desert and mountains biological reserve (Figure 1). More details can be found on the following web site: www.nevadawilderness.org.

The current Clark County designated CS-DWMA consists of two very narrow north-south contiguous strips of land (Figure 2). Nevertheless, the reality and multi-species conservation value of Coyote Springs is the entire DNWR landscape. The southern strip is the relatively narrow bajada (primarily Hidden Valley) on both sides of I93, bounded by Las Vegas Range (southeast portion of the Sheep Range) on the west and Arrow Canyon Range on the east, and NAFR and I93 on the south, and the Arrow Canyon wilderness on the north. The northern strip is bound on the west by I93, on the east by the Arrow Canyon Range, and on the north by C168. The north strip boundary is also the south boundary of the private residential development, Coyote Springs Investments (CSI), formerly known as Aerojet. The CSI development in Clark County is bounded by I93 on the west, Meadow Valley Mountains on the east, Lincoln County in the north, and C168 on the south.

Desert tortoises are typically found below 4000 feet, but have been recorded from significantly higher elevations. Although their habitat is widely acknowledged to be creosote/bursage scrub on gentle bajadas (see February Newsletter), I have found small populations thriving in rugged montane terrain at 4000-5000 feet in Joshua Tree National Park in the south-central Mojave. High elevation records for desert tortoises include: 7402 ft, Clark and 4800 ft Providence Mountains (California, just southwest of Piute-Eldorado DWMA); 4200 and 7300 ft, Death Valley National Park; 5240 ft, Yucca Mountain, NAFR, adjacent to DNWR and the Sheep Range (see Luckenbach 1982 and Grover and DeFalco 1995).

Desert springs and riparian areas are critical conservation landscape elements for resident, migratory, and over-wintering vertebrates and invertebrates. Their importance for birds has been widely documented, but they are also critical for amphibians, reptiles, mammals, and indeed all elements of biodiversity (see Figure 20, February Newsletter, Shipley web site). Both slopes of the Sheep Range, but especially the west slope, have many springs. Figure 3 shows a pond at Corn Springs, which has a very high species richness of birds and breeding populations of pacific chorus frogs (rare and fragmented in the Mojave), bullfrogs, and painted turtles. The latter two are introduced species. Vegetation layers are well developed with quail bush, four-winged saltbush (foreground) and honey mesquite (background), Figure 4.

The DNWR and Coyote Springs represent a major regional biodiversity refuge. Over 500 species of plants have been identified, and a broad diversity of resident, migratory, and wintering birds (over 320 species documented) and the desert tortoise are prominent biota. Twelve species of bats, 21 species of native rodents, 3 species of rabbits, common mammal predators (coyote, bobcat, gray and kit foxes, badger), rare mammal predators (mountain lions, ringtail cat, red fox), unusual southern Nevada mammals (porcupine, spotted and striped skunks), big game species (mule deer, desert bighorn, pronghorn), and at least 13 species of lizards, and 13 species of snakes have all been documented within this area. A number of other vertebrates also occur here, based on their distributional ranges and habitat preferences, but have not been officially documented. The rarest is undoubtedly the Hidden Forest Uinta Chipmunk. Its only known locality is in the Sheep Range (7700 and 8500 ft).

The western slopes of the Sheep range (5000 ft) typically consist of montane Mojave scrub with Joshua trees, Mojave yucca, blackbrush, shadscale, and Nevada Mormon tea (Figure 5). Note Charleston Peak (Spring Mountains) across I95, the highest point in the entire Mojave Desert (11,919 ft). Nearby washes are dense with vegetation (Figure 6). Shadscale scrub with scattered Joshua trees and the red “skeletons” of desert trumpet characterize the rocky bajada at 4500 ft (Figure 7). Creosote/bursage scrub is found in the lower bajada, here at 3200 ft (Figure 8). Note small and very sparse Joshua trees and Mojave yucca, beavertail cactus in foreground, and the patches of green spring oases in the background. These rocky bajadas may seem bleak, but they are home to an abundance of lizards, snakes, kangaroo rats, pocket mice, and invertebrates.

The Joshua tree “forest” is one of the major elevational plant communities in the Sheep Range (Figure 9). Note the association with Mojave yucca and blackbrush. This is along the Mormon Well trail at 4600 ft and the southeast extreme of the Sheep Range and west of Las Vegas Range. The geology is interesting and caves are present (Figure 10). Caves are very important landscape elements for bats, and also offer shelter for a wide variety of organisms. Peek-a-boo canyon (5300 ft) has well-developed riparian vegetation, with green Mormon tea visually dominant (Figure 11). The vegetation is becoming more complex at this elevation with the first appearance of both Utah juniper and piñon pine (Figure 12).

In a gentle cove at 5800 ft, junipers and piñon pines comprise a woodland, and low growing big sagebrush makes its appearance (Figure 13). The gentle rolling terrain at 6142 ft is dominated by blackbrush (small dark gray shrubs), but big sagebrush (foreground), both Nevada and green Mormon tea, and the scatter of junipers and piñon pines are also characteristic vegetation (Figure 14). Note the poor condition of Joshua trees in the foreground, affected by the colder temperatures at this elevation. The juniper and piñon pine woodland belt is very evident at just a slightly higher elevation (Figure 15). Note blackbrush in center foreground, big sagebrush at right, and scattered stressed Joshua trees.

At 6442 ft the juniper and piñon pine woodland with big sagebrush is well-developed (Figure 16). Scattered ponderosa pines with an understory of piñon pines, junipers, birch-leaved mountain mahogany, and red barberry was present at 6610-6700 ft (Figure 17). Ponderosa pine becomes more abundant and is found with white fir at elevations from 7500-9000 ft. Bristlecone pine is found at elevations greater than 8500 ft, and black sagebrush is found on south and west slopes at elevations over 9500 ft. Bristlecone pines may be the oldest living organisms on earth with an individual 4767 years of age in the White-Inyo Mountains of California near the Nevada border.

The vegetation of the east slope of the Sheep Range at Saw Mill Wash (5667 ft) is diverse with blackbrush, Joshua trees, green Mormon tea, four-winged saltbush, and scattered junipers and piñon pines (Figure 18).

Note the Arrow Canyon Range in the distance. Joshua tree woodland and blackbrush scrub is found at 4266 ft with Mojave yucca, Nevada Mormon tea, and turpentine broom (Figure 19). This is in the Las Vegas Range with a southwest view, with Sheep Range in the background, and is representative of the upper bajada of CS-DWMA and upper elevation of desert tortoise habitat. The view to the north toward Lincoln County demonstrates the large CS-DWMA bajada (Figure 20). Note the south edge of the Meadow Valley Mountains 16 miles away in the upper right, the location of the CSI development. Careful observation will reveal the small gap between these mountains and the north end of the Arrow Canyon Mountains just below and to the right. This narrow gap at C168 will be the only corridor between the CS and Mormon Mesa DWMAs when the CSI development is implemented. Further down the bajada (3192 ft) creosote/bursage scrub and Mojave yucca dominate the landscape in prime desert tortoise habitat (Figure 21). The extensive bajada to the north is evident with the Meadow Valley Mountains to the left and the Arrow Canyon Range on the right, and the “tortoise corridor” in between. Figures 20 and 21 represent a long distance landscape perspective of this corridor. For a better view of this corridor from the southwest see Figure 25, and from the northwest see Figures 56 and 78. The bajada at I93 is at 2600 ft with no changes in the plant community.

Just southeast of the intersection of I93 and C168, the northern tip of the Clark County CS-DWMA, is a rocky bajada with braided washes and vigorous vegetation, 2431 ft (Figure 22). Sweetbush, indigo bush, Mojave yucca, and cacti are abundant. The view is east toward the north end of Arrow Canyon Range.

A southeast view along the mountain range demonstrates good rocky bajada habitat (Figure 23). The eastern bajada of Sheep Range, and excellent desert tortoise habitat, is seen across I93 in the western view (Figure 24). Figure 25, directed to the northeast shows the only corridor for desert tortoises between Mormon Mesa and Coyote Springs DWMAs. It is the narrow “gap” in the distance between the north end of Arrow Canyon Range on the right and the foothills of Meadow Valley Mountains on the left. The road through the gap is C168. For a view of this corridor from the northwest see Figures 56 and 78.

Excellent creosote/bursage habitat with Mojave yucca is found six miles south on I93 from its intersection with C168, 2400 ft, Las Vegas Range in foreground and Sheep Range in background (Figure 26). Mojave yucca is less abundant here, but there is still good plant diversity with Pima rhatany and several species of cactus being prominent. Looking north the bajada represents an extensive view of desert tortoise habitat (Figure 27).

The bajada west of I93 is wide, but very narrow east of the highway. The high cover of red brome grass (introduced from the Mediterranean and an extremely invasive species) poses a fire hazard along I93 (Figure 28). Four miles further south there is dumping and burning near the highway, 2725 ft, (Figure 29). Note the invasive Russian thistle in disturbance patches contrasted to creosote/bursage in the background. Volcanic outcrops add to the diverse geology of the Sheep Range bajadas (Figure 30).

Five miles further south on I93 there is an unusual playa depression in the creosote scrub, 2623 ft (Figure 31). Creosote bush, the dominant plant, is doing very well in association with four-winged saltbush and desert tomato, but burroweed (white bursage) is absent. Saltbush taxa in particular, and occasionally desert tomato, are associated with true playas edges, but not creosote bush. Playas are low depressions to large basins in deserts where there is standing water after precipitation. The soils with the accumulation of clay and silt tend to be finely textured (and therefore not well aerated), alkaline, and saline. Creosote is typically found on well-drained soils, but can be found on heavier soils that do not become excessively water logged or anaerobic. The light colored patches are highly cracked soils, providing evidence of pooled water evaporation. The darker areas are highly developed cryptogamic crusts. These crusts are biologically active and important nitrogen fixers in arid environments. They consist of lichens, bacteria, and cyanobacteria (blue-green algae). Kangaroo rat burrows and occasional OHV tracks were present.

Seventeen miles from I93-C168 intersection there is a casually used refuse dump (light patch in distance along I93) in excellent creosote/bursage scrub and yucca woodland (Hidden Valley), 2766 ft (Figures 32, 33).

Mormon Mesa DWMA

The original Mormon Mesa DWMA consisted of a large parcel whose western boundary was I93, and to the south crossed I15 east of Glendale and continued down to Lake Mead following the shores of the Muddy and Virgin Rivers, and in a narrow corridor was contiguous with the Beaver Dam Slope DWMA in extreme northwestern Arizona (USFWS 1994). The current Clark County MM-DWMA (Figure 2) is a thin east-west sliver; with Lincoln County as the north, I15 the south, and Toquop Wash the east boundaries. MM-DWMA in Clark County is now separated from the Beaver Dam Slope, but in Lincoln County it should still be contiguous with the Beaver Dam Slope in both Arizona and Utah. The western boundary is a diffuse area encompassing CS-DWMA (east of I93) and the CSI property, and includes a small section of Pahranagat Wash between Arrow Canyon Range and C168. This section is the only future desert tortoise corridor between the two DWMAs, because of the barrier effect of the CSI development on the north side of C168 (see Figures 2, 25, 56, 78).

Figure 34 shows the northeastern corner of MM-DWMA, north of I15 looking toward East Mormon Mountains, approximately 12 miles west of Mesquite (2272 ft). The area is a gravelly bajada creosote/bursage scrub with highly weathered and disintegrating carbonate rocks (caliche). The habitat contains a diversity of scattered plants, including Joshua trees, indigo bush, and a surprising diversity of cacti: buckhorn cholla, silver cholla, beavertail, hedgehog, grizzly bear prickly pear, and barrel. Rigid spiny herb is abundant in its preferred gravelly substrate (Figure 35).

The landscape has numerous braided shallow washes with high densities of cheesebush, sweetbush, and larger more vigorous representatives of upland species (Figure 36). Eroded caliche caves at the edges of washes provide desert tortoises with natural burrows (Figure 37). Caliche burrows are up to 36 ft deep on the Beaver Dam Slope and provide critical hibernacula for desert tortoises (and snakes) in the northern part of their range. Occasional refuse dumping can be found closer to I15, Mormon Mountains in distance (Figure 38). In arid environments, refuse persists for many decades.

North of I15 and approximately 7 miles east of Meadow Valley Wash, the southern portion of MM-DWMA possesses excellent desert tortoise habitat, dense creosote/bursage scrub with loamy sandy soils, 2018 ft (Figure 39). Mormon Mountains are in the background. Kangaroo rat burrows were very abundant all over the extensive bajada. A bony shell and several horny dermal scutes are all that remained of this desert tortoise carcass (Figure 40). Lower down the bajada is an area with loose eolian sandy soils where big galleta grass is associated with creosote bush, Nevada Mormon tea, Pima rhatany, and turpentine broom, 1997 ft (Figure 41). Kangaroo rat, lizard, and snake tracks were abundant.

North of Moapa at Meadow Valley Wash the MM-DWMA consists of gravelly creosote/bursage scrub, 1742 ft (Figure 42). This is a northeast view showing the rugged western edge of the geological Mormon Mesa, with Mormon Mountains in the distance.

Warm Springs along the Pahranagat Wash is a historically developed small residential community along C168 that has an ample water supply from wells and springs (Figure 43). Pahranagat and Meadow Valley Washes combine near Glendale to form the Muddy River which enters Lake Mead southeast of Overton.

The western end of MM-DWMA north of Pahranagat Wash and C168, and approximately midway between this wash and Meadow Valley Wash, displays a vibrant and diverse habitat on the small mesa extending south from the Meadow Valley Mountains and Bunker Hills, 2148 ft (Figure 44). The soils here are loamy sand to sandy. Note the rich gray-green color of burroweed. This species readily drops its leaves during drought periods, and is usually observed leafless. Creosote bush, on the other hand, maintains its leaves, depending instead on deep tap roots and an unusually high physiological tolerance to desiccation. The view is to the north looking at the rugged terrain of the Bunker Hills and foothills of the Meadow Valley Mountains. The survey poles may be for water exploration, and probably belong to the CSI development west of here. Figure 45 shows a view to the west with a green band of vegetation, the drop-off to the Pahranagat Valley and Wash, and the Sheep Range in the distance. Compare the color of burroweed in the foreground and background in this Figure and in Figure 44. Figure 46 is a close-up of the green band of vegetation in the previous Figure. This is shallow and broad sandy wash where burroweed, creosote bush, big galleta grass, sweetbush, and four-winged saltbush were extremely vigorous. Figure 47 is an east view along one of the major sandy washes in the area, demonstrating the vigor of the vegetation. The water table must be close to the surface in this area, because of the drainages of many small washes (e.g., Wildcat Wash, Dead Man Wash, and McKay Wash).

Mormon Mesa, South of I15

Mormon Mesa is the geologic uplift south of I15, and was included in the original MM-DWMA (USFWS 1994). This area is defined by I15 in the north, the Virgin River in the east, C169 and the towns of Logandale and Overton to the west, and Lake Mead to the south where the Virgin and Muddy Rivers join. The southwest edge of Mormon Mesa is shown in Figure 48.

The northeastern Mormon Mesa, south of I15 and near the Old Spanish Trail is a flat creosote/bursage plain with patches of desert pavement, scattered OHV tracks, silver cholla and widely scattered Joshua trees, note barrel cactus in foreground and Virgin Mountains in distance, 2060 ft (Figure 49). Kangaroo rats and associated biota appear to be abundant. Along the old trail the asphalt is disintegrating at wash crossings (Figure 50). A large wash with extensive head cutting is on its way to the Virgin River (Figure 51).

The southern portion of Mormon Mesa is a flat monotonous creosote/bursage scrub plain, 1814 ft (Figure 52). This is a north view with the Mormon Mountains in the background. Note the well-worn kangaroo rat trail to its burrow in the foreground. The view east across the Virgin River toward the Virgin Mountains demonstrates OHV tracks in foreground (Figure 53). The mesa has been impacted by occasional OHV activity. Occasionally, there are large patches of bare areas covered with cryptogamic crusts (Figure 54). These are biologically active crusts that fix nitrogen and provide soil surface integrity, retarding wind and water erosion. Figure 55 looks southwest off the mesa edge at Overton.

Coyote Springs Investments Development Area

The CSI area was originally in the MM-DWMA, because its western boundary was I93. The CSI area in Clark County is 20,648 acres, and to the north in Lincoln County is 22,140 acres. The southern and eastern boundaries are respectively C168 and Meadow Valley Mountains. The following pictures were taken in September 2004 when the habitats at virtually all of the DWMAs were very dry, as expected during the fall in the Mojave after a hot dry summer. The Mojave Desert derives all or most of its precipitation from winter rains. Summer rains are severe and brief thunderstorms, which are infrequent, unpredictable, and highly variable and patchy in both space and time.

The rocky bajada at CSI just northeast of the intersection of I93 and C168 (2460 ft) was botanically species rich and the vegetation was relatively green, suggesting that either ground water was close to the surface or the area experienced above normal summer precipitation, because of the close proximity to the rainfall catching high peaks of the Sheep Range to the west (Figure 56). The habitat is diverse creosote/bursage scrub and Mojave yucca woodland, with indigo bush, Pima rhatany, desert trumpet, and many species of cacti (silver cholla, beavertail, barrel, and hedgehog). The view is to the southeast with C168 in the background and the narrow desert tortoise movement corridor between the Arrow Canyon Range to the south (right side of image) and Meadow Valley Mountains to the north (left and center of image). This is the only corridor for desert tortoise genetic integrity between Coyote Springs and Mormon Mesa DWMAs. See also Figure 25 for a view from the southwest and Figure 78 for another northeast view. Note that the topography drops eastward from this bajada, and the Meadow Valley Mountains in the distance. This trough is Pahranagat Wash. The northeast view overlooking the CSI, with Pahranagat Wash and Meadow Valley Mountains in the distance, shows Lincoln County and the Delamar Mountains in the far landscape on the left (Figure 57). The bajada is characterized by a landscape-scale extensive network of braided washes, where the vegetation is particularly vigorous (Figure 58). Sweetbush is a diagnostic species in small ephemeral washes (Figure 59). Figure 60 shows a west view across I93 toward the Sheep Range.

Vegetation at the CSI site on 28 March 2005 after a wet winter and in a shower appears very vigorous, note heavy cloud cover, 2460 ft (Figure 61). Construction activities began in early 2005, and the orange fencing is an attempt to protect the vegetation and soils in major washes (Figure 62).

Nevertheless, the braided washes are so extensive on this bajada that only the larger and more obvious washes will be afforded protection from disturbance. Red brome, a very invasive exotic annual grass from the Mediterranean, responds rapidly to winter rains, and is usually associated with major vegetation such as Mojave yucca (Figure 63) or creosote bush (Figure 64), also see Figure 28.

In general, forbs and grasses are typically associated with desert shrubs, with bare patches of low microbial activity and soil nutrients (Figure 65). Cacti respond very well to precipitation by absorbing large quantities of water into their tissues through their shallow but extensive network of roots. Grizzly bear prickly pear cactus has unusually long spines; note the abundance of small white flowers in the ground cover (Figure 66).

Further down the CSI bajada (eastward) (2234 ft) is a section of eroding sparsely vegetated sedimentary hills, view to the west, and note the barely visibly orange fencing at the top of the bajada (Figure 67). Figure 68 shows the perspective to the background of the Las Vegas and Sheep Ranges on the western horizon. The sandy washes in these hills are rich with vegetation (Figures 69, 70).

The extensively braided shallow washes of the upper bajada join into larger and more deeply incised arroyos in these hills, flowing to Pahranagat Wash (Figure 71 and Figure 72 – Meadow Valley Mountains in the background). The eroding hills themselves form complex alluvial patterns, Sheep Range in background (Figure 73). The dendritic pattern of smaller washes fuses into larger washes, 2227 ft (Figure 74).

The washes finally empty into a broad plain above Pahranagat Wash (Figures 75, 76). Note the color changes in the plain above the wash, indicating different vegetation zones, and the presence of trees in the distant wash (Figure 77). These vegetation zones are discussed below. The view to the southeast shows the narrow desert tortoise corridor between the Arrow Canyon Range to the south (right side of picture) and the Meadow Valley Mountains on the far left, the thin band in the center is C168 (Figure 78).

See also Figure 25 for a view from the southwest and Figure 56 for another northeast view. The view to the west depicts the entire CSI bajada before descending to the Pahranagat Wash plain (Figure 79). The three small white dots are trailer trucks on I93.

The upper-most plain above Pahranagat Wash is a well-watered creosote/bursage scrub with loamy sandy soils, note the vigorous gray-green leaf growth on burroweed and the low hills/wash complex in the background (west) that drain into this plain (Figure 80, see also Figure 78). This is the foreground of Figure 77. Closer to the wash the burroweed disappears, but creosote is vigorous with individuals up to 6 ft in height (Figure 81). The ground cover consists of an unidentified weed and yellow evening primrose in bare sandy patches (Figure 82).

This riparian terrace is the bright green band seen in Figure 76. The small grass is the Asian exotic annual, Mediterranean grass. The clayey cracked soil indicates the evaporation of standing puddles. The riparian zone consists of loose sandy hummocks with vigorous creosote bush and Mediterranean grass (Figure 83). Note the flooding debris trapped against creosote bush (Figures 83, 84).

A characteristic plant here is desert rhubarb (Figure 85), and the large desert kangaroo rat and exotic Mediterranean grass are partial to loose sandy soils (Figure 86). Creosote bush and desert kangaroo rats are not characteristic of floodplain zones. Therefore, this area must rarely be under water, and the high flooding this year was atypical. Possibly, much of the flow of Pahranagat Wash is underground, percolating through the very sandy soils.

The major vegetation along the wash is four-winged saltbush, desert rhubarb, and desert willow, 2162 ft (Figure 87, 88, 89). The desert willow is not a true willow, is cultivated for its beautiful flowers, and belongs in the family Bignoniaceae. Although it was still early in the season (29 March), most of the branches, if not entire trees, appeared desiccated (Figure 89). The wash was wide in some places (Figures 90, 91), and even braided (Figures 92, 93). Based on the debris line in desert willow, water depth was at least 5 ft in the wash during the winter of 2004-2005. A careful observation of Figure 94 shows the entire seven topographical and botanical landscapes: Pahranagat Wash and riparian zone, the creosote “floodplain”, creosote/bursage scrub (thin grayish band just before the hills), the low eroding hills dissected with washes, the long rocky bajada that crosses I93, Las Vegas Range, and the snow-covered Sheep Range. Pahranagat Wash when it crosses C168 is not visually impressive (Figures 95, 96). This is further evidence that the primary alluvial flow in the wash is subsurface.

The CSI development has planned to avoid the wash and associated 100-year old floodplain. However, it is not clear how CSI water drawdown will allocate its use between these alluvial flows, critical to instream and downstream ecosystems and the Muddy River, and the deep fossil aquifer.

The upper bajada (creosote/bursage scrub, 2555 ft) of the western slope of Meadow Valley Mountains looking toward CSI and Sheep Range is shown in Figure 97. The landscape drop is to Pahranagat Wash. Careful observation in the upper right of the image shows the intersection of C168 and I93 (i.e., CSI development). The road in the upper left is Mormon Well Road through the Sheep Range. The habitat in the vicinity of this road is shown in Figure 20.

Figure 98 (2412 ft) at 2.5 miles further north shows the Meadow Valley Mountains. The creosote/bursage gravelly bajada has scattered Mojave yucca, silver cholla, Nevada Mormon tea. Patches of desert pavement are also present, view toward Sheep Range (Figure 99).

Two miles further north at the Lincoln County line the rolling gravelly bajada with extensive braided shallow washes is characterized by complex creosote/bursage scrub with Mojave yucca, Nevada Mormon tea, turpentine broom, Pima rhatany, indigo bush, and silver cholla, 2442 ft, view of Meadow Valley Mountains just to the east (Figure 100). The red vegetation is skeletons of desert trumpet (Figure 101). The grizzly bear prickly pear is a beautiful cactus with long flowing spines (Figure 102, see also Figure 66).

Figure 103 shows the view to the north and the large expanse of the bajada in Lincoln County, the Delamar Mountains are in top center, and the north end of the Sheep Range in the upper left. Figure 104 shows the view to the south and the north end of the Arrow Canyon Range. Figure 105 shows the west view to the Sheep Range. The Meadow Valley Mountains and its western bajada represent high quality habitat.

Literature Cited

Forman, R.T.T., and 13 other authors. 2003. Road Ecology: Science and Solutions. Island Press, Washington, D.C. 481pp.

Grover, M.C., and L.A. DeFalco. 1995. Desert Tortoise (Gopherus agassizii): Status-of-Knowledge Outline with References. U.S. Forest Service, General Technical Report INT-GTR-316. 134pp.

Knight, R.L., and K.J. Gutzwiller, eds. 1995. Wildlife and Recreationists: Coexistence Through Management and Research. Island Press, Washington, D.C. 372pp.

Langton, T.E.S., ed. 1989. Amphibians and Roads. ACO Polymer Products Ltd., Bedfordshire, England. 202pp.

Luckenbach, R.A. 1982. Ecology and management of the desert tortoise (Gopherus agassizii) in California. Pages 1-37 in North American Tortoises: Conservation and Ecology. R.B. Bury, ed. U.S. Fish and Wildlife Service, Wildlife Research Report 12, Washington D.C. 126pp.

Sherwood, B., D. Cutler, and J.A. Burton, eds. 2002. Wildlife and Roads: The Ecological Impact. Imperial College Press, London. 299pp.

USFWS. 1994. Proposed Desert Wildlife Management Areas for Recovery of the Mojave Population of the Desert Tortoise. U.S. Fish and Wildlife Service, Dept. of the Interior, Portland, OR. 100pp.

Scientific Names

Plants (February and April Newsletters)

banana yucca (Yucca baccata)
barrel cactus (Ferocactus cylindraceus, formerly F. acanthodes)
beavertail cactus (Opuntia basilaris)
big galleta grass (Pleuraphis rigida, formerly Hilaria rigida)
big sagebrush (Artemisia tridentate)
birch-leaf mountain mahogany (Cercocarpus betuloides)
blackbrush (Coleogyne ramosissima)
black sagebrush (Artemisia nova)
bristlecone pine (Pinus longaeva)
buckhorn cholla (Opuntia acanthocarpa)
burroweed or white bursage (Ambrosia dumosa)
California buckwheat (Eriogonum fasciculatum)
California juniper (Juniperus californicus)
catclaw acacia (Acacia greggii)
cheesebush (Hymenoclea salsola)
cottontop cactus (Echinocactus polycephalis)
cottonwood (Populus fremontii)
creosote bush (Larrea tridentata)
desert rhubarb (Rumex hymenosepalus)
desert tomato (Lycium andersonii)
desert trumpet (Eriogonum inflatum)
desert willow (Chilopsis linearis)
filaree, see heron’s bill
four-winged saltbush (Atriplex canescens)
green Mormon tea (Ephedra viridis)
grizzly bear prickly pear (Opuntia erinacea)
hedgehog cactus (Echinocereus engelmannii)
heron’s bill or filaree (Erodium cicutarium), introduced
honey mesquite (Prosopis glandulosa)
indigo bush (Psorothamnus arborescens)
Joshue tree (Yucca brevifolia)
Medeterranean grass (Schismus arabicus, S. barbatus), introduced
Mojave yucca (Yucca shidigera)
Nevada Mormon tea (Ephedra nevadensis)
Pima rhatany (Krameria erecta, formerly K. parvifolia)
piñon pine (Pinus monophyla)
ponderosa pine (Pinus ponderosa)
quail bush (Atriplex lentiformis)
red barberry (Berberis haematocarpa)
red brome (Bromus madritensis, formerly B. rubens), introduced
Russian thistle or tumbleweed (Salsola tragus), introduced
formerly S. australis, S. iberica, and S. kali, all misapplied
saltcedar or tamarisk (probably Tamarix ramosissima, complex taxa), introduced
shadscale (Atriplex confertifolia)
silver cholla (Opuntia echinocarpa)
skeleton weed (Eriogonum deflexum)
sweetbush (Bebbia juncea)
tamarisk, see saltcedar
teddy bear cholla (Opuntia bigelovii)
tumbleweed, see Russian thistle
turpentine broom (Thamnosma montana)
Utah Juniper (Juniperus osteosperma)
white bursage, see burroweed
white fir (Abies concolor)
willow (Salix gooddingii, S. exigua, and others)
yellow evening primrose (Oenothera primaveris)

Recommended plant guides

Introductory:
Mojave Desert Wildflowers, Pam MacKay, 2003
A Falcon Guide, Guilford, CN. 338pp.

Introduction to California Desert Wildflowers, Philip A. Munz, 2004
University of California Press, Berkeley, CA. 235pp.

California Desert Flowers, Sia Morhardt and Emil Morhardt, 2004
University of California Press, Berkeley, CA. 284pp.

Advanced:
The Jepson Desert Manual: Vascular Plants of Southeastern California,
Bruce G. Baldwin and six other editors, 2002
University of California Press, Berkeley, CA. 624pp.

Animals (special reference)

bullfrog (Rana catesbeiana), introduced
desert tortoise (Gopherus agassizii)
desert kangaroo rat (Dipodomys deserti)
Hidden Forest Uinta chipmunk (Tamias quadrivittatus nevadensis)
Pacific chorus frog (Pseudacris regilla)
painted turtle (Chrysemys picta), introduced