Natural History of the Granite Mountains

 

The east Mojave Desert represents one of North America’s most pristine natural landscapes, with parts of two national parks, a national preserve, and over 40 wilderness areas. Its vast open space is punctuated by rugged mountain sky-islands, braided bajadas, sprawling lava flows, singing sand dunes, and saline playas. From broad expanses of creosotebush to isolated stands of white fir, the east Mojave Desert is a land of high floristic and faunal diversity just beginning to be understood, a fertile opportunity for research and teaching.

The Granite Mountains are one of the largest ranges in the east Mojave Desert, located at the southern terminus of a long chain of ranges that extends northward into the Great Basin Desert of Nevada. The range lies within a transition zone between the Colorado (Sonoran) Desert to the south, the Great Basin Desert to the north, the Colorado Plateau to the east, and the western Mojave Desert. This position, in addition to obtaining some of the higher elevations in the Mojave Desert, is reflected in the range’s diverse plant and animal communities, which include many species at the margin of their geographical distributions.

The Sweeney Granite Mountains Desert Research Center lies on the eastern slopes of the Granite Mountains. Upslope, the reserve rises amid pinyon- and juniper-covered ridges to the highest peak in the Granite Mountains (2,071 m / 6,796 ft). From there, large watersheds descend precipitously to the north and east into the sandy alluvial valleys of Bighorn Basin, Cottonwood Basin, and Granite Cove. The lower slopes are characterized by fractured granitic canyon walls and outlying boulders, with vertical faces rising up to 150 m (~ 500 ft). Near the Center’s eastern boundary, large boulders and exposed pediment give way to densely vegetated bajadas and washes. Springs and seeps with associated wetland plants and invertebrates are common throughout the site.

Climate

The East Mojave climate is characterized by low rainfall and low humidity, broad temperature variation, and strong winds (especially in winter). The reserve’s steep elevational gradients (843 m / 3,096 ft) produce a wide range of climatic conditions.

The Center has been monitoring temperature and precipitation in Granite Cove since 1986. A Campbell weather station was installed in 2000, collecting data on additional parameters including wind direction and speed, soil moisture and temperature, solar radiation, and relative humidity. Summarized on the weather data page are precipitation and temperature data over a 20 year period (1986-2006). Mean annual precipitation in Granite Cove is 23 cm (9.0 in). Average annual precipitation is estimated to be about 2-4 cm greater near Granite Peak on the west boundary of the Center. Annual totals vary widely among years, and from location to location within a year. Unlike the west Mojave Desert, which is relatively dry in summer, a substantial percentage of the annual precipitation in the east Mojave Desert occurs during the summer monsoon. The principal source of winter precipitation is from moist Pacific frontal systems or cold Great Basin troughs. Light winter snows are common, and a snow pack may even accumulate at elevations above 1,900 m (~ 6,000 ft). And though some of the earth’s hottest temperatures are recorded in adjacent valleys, peak summer temperatures at the Center are relatively mild, with an average high of 94 and low of 72 deg F. The highest temperature recorded at Granite Cove to date is 41.6ºC (107ºF); the coldest winter temperature is – 11ºC (11ºF).

Geology

The Granite Mountains are largely comprised of Mesozoic (63 to 240 million years old) plutonic rocks. Small pendants of Paleozoic (240 to 570 million years old) metasedimentary rocks include marble, siliceous marble, dolomite marble and calsilicate hornfels. Tertiary (2 to 63 million years old) igneous dikes, volcanic rocks, coarse sedimentary debris, and Quarternary (2 million years and younger) alluvium are present around the flanks of the range.

The east portion of the Granite Mountains within the Center contains some of the most outstanding examples of exposed granite pediment in North America. Here the pluton is exposed Jurassic (138 to 205 million years old) quartz monzonite and Cretaceous (dated at 71 to 75 million years old) granodiorite. Weathering along joints and fractures has produced massive white pinnacles and complex mazelike corridors that dominate the landscape.

The Granite Mountains are located within 50 kilometers (~30 mi) of several high calcareous mountain ranges (e.g., Providence and New York Mountains), sand dunes (Kelso and Cadiz Dunes), lava flows (Cima Cinder Cones and Amboy Crater), and extensive alluvial fans. Many of the alluvial surfaces in the region have been dated using a variety of techniques in conjunction with research on the formation of alluvial fans and periodic sand deposition events.

Vegetation
Photo Gallery I Species List I Printer Friendly Species List

The classification of vegetation types in the Granites Mountains presented here is based primarily upon previous field work and associated publications (Hart et al. 1979, Thorne et al, 1981, and Andre 2006). The associations are presented zonally from the highest to lowest elevation. The names of the vegetation types combine floristic, physiognomic, and physiographic designations weighted towards the most conspicuous aspect of the association. A list of dominant or characterisitic taxa will be provided with each type.

Pinyon-Juniper Woodland Most prominent on higher elevation ridgetops and rocky slopes, this usually open coniferous woodland is dominated by single-leaf pinyon pine (Pinus monophylla) and Utah juniper (Juniperus osteosperma). Though this type is best developed above 1600 m, stands may occur in the mesic microsites among boulders down to as low as 1100 m. Rarely do these trees exceed a height of 7 or 8 m, but some have been dated to as old as 500 years. Near the Granite Pass area, a local and northern disjunct population of the strictly shrubby California juniper (Juniperus californica) is found. The flora of the Pinyon-Juniper Woodland is relatively rich in shrubs and perennial herbs, but annuals are noticeably few. The more characteristic shrub species associated with this type include: Ephedra viridis, Yucca baccata, Eriogonum wrightii wrightii, Ericameria linearifolius, Tetradymia argyraea, Artemisia tridentata parishii, Rhamnus ilicifolia, Purshia tridentata glandulosa, and Garrya flavescens. On the precipitous bouldered slopes, common herbaceous taxa include: Euphorbia incisa, Elymus elymoides multisetus, Penstemon eatonii, Poa secunda, Achnatherum speciosa, and Arabis perennans

Pinyon-Juniper Woodland – Cliffs and Boulders This association represents an edaphically-derived subset of the above type. Where Pinyon-Juniper Woodland is interrupted by cliffs and towering boulders on the eastern slopes of the Granite Mountains, numerous “boulder-obligate” species are found inhabiting the vertical cliffs, rock-crevices and base of boulders. These include Ericamaria cuneatus, Brickellia arguta, Galium stellatum, Eriogonum heermannii, Keckiella antirrhinoides, Ivesia saxosa, Poa fendleriana, Ericameria laricifolius, Dudleya saxosa, Cheilanthes covillei, and Pellaea mucronata.

Blackbush Scrub Located between 1300-2000 m in the Granite Mountains, this low-growing vegetation type is dominated by blackbush (Coleogyne ramosissima). Elsewhere in the Mojave Desert, blackbush scrub may cover extensive areas and is often associated with Joshua tree woodland. In the Granites, blackbush scrub is more limited, growing in mostly small patches on ridgetops and slopes on thin gravelly soils. It stands out from other scrub associations by its dark gray hue and dense uniform structure. Few vegetation associations in the Mojave Desert are dominated by a single species as is blackbush scrub, thus there are no prevalent associates to blackbush in this type. Occasional associates may be found however, including: interior goldenbush (Ericameria linearifolia), old man cactus (Opuntia erinacea), prickly pear (Opuntia phaecantha) and hopsage (Grayia spinosa).

Mixed Woody Scrub This common and relatively diverse type occurs on exposed pediments and bajadas at lower elevations (below 1300 m (4264 ft.)). It is co-dominated by 10 to 15 shrub species, including: Acamptopappus sphaerocephalus, Eriogonum fasciculatum, Encelia frutescens, Salazaria mexicana, Ericameria cooperi, Opuntia acanthicarpa and Yucca schidigera. Unlike the Pinyon-Juniper Woodland, annual species make up more than 50% of the species in this association, and may include:Eriophyllum wallacei, Linanthus aureus decorus, Amsinckia tessellate, Camissonia claviformis, Phacelia distans, Eschscholzia minutifolia, Pectocarya setosa, Gilia sinuata, Eriogonum pusillum and Pectis papposa.

Enriched Woody and Succulent Scrub Located along the upper bajada slopes of the eastern side of the range, this complex plant association is notable for its impressive shrub diversity and dense cover. Between 15-25 co-dominant shrubs share this type, comprising all of the species in the Mixed Woody Scrub association, but also including Opuntia echinocarpa, O. ramosissima, Echinocereus englemanii, Coleogyne ramosissma, Thamnosma montanta, Lycium cooperi, L. andersonii, Grayia spinosa, Ephedra nevadensis, Encelia virginensis, Xylorhiza tortifolia, and Psorothamnus arborescens minutifolius.

Creosote Bush Scrub An open shrubland dominated by Larrea tridentataand Ambrosia dumosa, this vegetation type is ubiquitous not only surrounding the Granite Mountains on bajadas and flats with well-drained soils below 1300 m (4264 ft.), but throughout the Mojave Desert as well. Generally a fairly simple assembledge, in addition to the two dominant species, several subdominants may also occur includingKrameria erecta, Lepidium fremontii, Sphaeralcea ambigua, Stephanomeria pauciflora, Senna armata, Gutierrezia microcephala and Hymenoclea salsola.

Desert Psammophytic Scrub Though the Kelso Dunes are not included within the Granite Mountains, aeolian deposits from the dunes occur along the lower bajadas on the north side of the range. These sandy deposits support a psammophytic vegetation type that is transitional and related to the sandier phases of Creosotebush Scrub. Larrea tridentata is often present and frequently the dominant species, but the vegetation type is distinguished by a large number of species restricted entirely to desert dunes. Some of these include: Pleuraphis rigida, Oryzopsis hymenoides, Croton californica, Lupinus shockleyi, Abronia villosa, Rumex hymenosepalus, Machaeranthera leucanthemifolia, Palafoxia arida, and Baileya pauciflora.

Wash Scrub Where watercourses widen into broader sandy washes, a distinct riparian scrub type develops, dominated by Acacia greggii, Prunus fasciculata, Hymenoclea salsola, Petalonyx thurberi, Rhus trilobata, Senecio flaccidus monoensis, Chrysothamnus paniculatus, Ambrosia eriocentra andBebbia juncea. Larger washes, such as in Cottonwood Basin, are lined with desert willow (Chilopsis linearis) forming a thicket in places.

Springs, Seeps, and Riparian Woodland In canyons throughout the range where permanent water is at or near the surface, vegetation is dominated by facultative or obligate wetland plants. There are more than 50 springs in the Granite Mountains, and numerous deeply incised canyons that support seasonal or permanent water flow (e.g., Bull Canyon). These may support a small woodland comprised of Populus fremontii, Prosopis glandulosa, Quercus chrysolepis and Salix gooddingii, Also frequent in these areas are shrubs like Salix exigua, Baccharis sergiloides, Artemisia dracunculus, A. ludoviciana, and the non-native Tamarix ramosissima. In moist soils on the banks of watercourses or at seeps, a suite of herbaceous wetland plants occur, including: Juncus mexicanus, Solidago confinis, Mimulus guttatus, Sisyrinchium halophilum, Eleocharis parishii, Carex alma, Muhlenbergia rigens, and Phragmites australis.

Floristics

A number of floristic summaries have been produced for portions of this area, in particular those by Hart et al. (1979) Thorne et al. (1981), and most recently by Andre (2006). Here we summarize the findings from Andre (2006).

For this analysis, the floristic area of the Granite Mountains totals 27,700 ha (107 sq. mi). Its perimeter boundaries are delineated as follows: East boundary – Kelbaker Road from I-40 north to transmission line dirt road 200 m. south of the access road to the Kelso Dunes; North boundary – the transmission line dirt road along the south end of the Kelso Dunes, from Kelbaker Rd west to the Mojave National Preserve (MNP) boundary at Budweiser Wash; West boundary – the southwest corner of the MNP boundary from the transmission line dirt road at Budweiser Wash (near Kelso Dunes) south to I-40; South boundary – along I-40 and the MNP boundary, from the southwest corner of the MNP boundary east to Kelbaker Rd.

To date, the vascular flora of the Granite Mountains consists of 70 families, 255 genera and 498 specific and intraspecific taxa. A surprising total of 91 of the taxa were added to the flora since 1994. Of the 498 taxa, 459 are native, 13 are listed by the California Native Plant Society, 33 are non-native invasives, and 6 are historic cultivars. For the following analyses of the flora by various components, the 6 taxa that are historic cultivars are not considered, thus reducing the “naturalized and naturalizing” flora to a total to 68 families, 250 genera, and 492 taxa (Table 1).

Table 1. Taxonomic Classification of the Vascular Plants in the Granite Mountains Flora

Families

Genera

Species

% of all Species

Pteridophytes

1

5

9

1.8

Gymnosperms

2

2

3

0.6

Gnetophytes

1

1

4

0.8

Dicots

58

209

410

83.3

Monocots

6

36

66

13.5

The ten largest families comprise 64% of the taxa in the study area, as shown in Table 2. As is the case in most floras in the western U.S., the Asteraceae is by far the largest family, representing 19% of the taxa. Approximately 40% of the families listed for California (Hickman 1993) are found in the Granite Mountains.

Table 2. Ten Largest Families of Vascular Plants in the Granite Mountains Flora

Family

# of genera

# of species

% of all species

Asteraceae

54

94

18.9

Poaceae

22

45

9.0

Polemoniaceae

9

30

6.0

Polygonaceae

7

27

5.4

Fabaceae

8

24

5.0

Brassicaceae

16

23

4.7

Boraginaceae

6

21

4.2

Hydrophyllaceae

7

20

4.0

Onagraceae

3

17

3.4

Scrophulariaceae

5

14

2.8

Totals

139

317

64%

The eastern Mojave Desert region contains a number of large, evolutionarily dynamic genera that appear to have undergone relatively recent radiations. Six of the 255 genera in the Granite Mountains Flora contain 15% of all taxa in the flora (Table 3). The Granite Mountains flora exemplifies the transitional nature of the east Mojave Desert. Floral elements derived from the Great Basin and Sonoran Deserts interact with Mojave Desert endemics. Greatest affinities, however, seem to be with the southern deserts due to the southwestern most position of the Granites in the north-to-south chain of high ranges in the east Mojave.

Table 3. Six Largest Genera of Vascular Plants in the Granite Mountains Flora

Genus

# of taxa

% of all taxa

Eriogonum

19

3.8

Phacelia

13

2.6

Cryptantha

12

2.4

Gilia

12

2.4

Astragalus

10

2.0

Camissonia

10

2.0

Totals:

76

15%

A total of 33 non-native invasive plants were documented in the flora representing 8% of the total number of species (Table 4). Many of these, however, were isolated waifs. The effective naturalizing exotics represent only about 4% of the flora. Regardless, this is a relatively small proportion compared to the entire California flora, which is 17% non-native. With 459 native taxa, the Granite Mountains flora encompasses 33% of the taxa in the California Mojave Desert (Baldwin et. al., 2002) in an area less than 0.5% of the California Mojave desert. About 46% of the natives are annuals, whereas 82% of the exotics in the flora are annuals.

Table 4. Summary of Life-Forms in the Granite Mountains Flora

Annual

Perennial Herb

Suffruticose Perennial

Shrub

Tree

Native

199

120

38

93

9

Non-native

27

4

1

1

0

Total (%)

226 (46)

124 (25)

39 (8)

94 (19)

9 (2)

The Granite Mountains represent one of many dozens of mountain ranges in the east Mojave Desert, and one of the most floristically studied areas of the Mojave Desert. And while floristic study of this range has been comprehensive, it is still a work in progress as additional taxa continue to be added. Clearly, the less collected ranges and basins in the east Mojave remain even greater frontiers for floristic discovery.

Amphibians
Herps Species List

The red-spotted toad (Bufo puctatus) is the only amphibian species recorded in the Granite Mountains and is the only amphibian species known to occur throughout most of the Mojave Desert. Calls of the California treefrog ( Hyla cadaverina ) have been heard, but no adult voucher specimens have been collected.

Reptiles
Herps Species List

Of the 15 lizard and 18 snake species at the Granite Mountains, 80 percent are commonly found throughout the Mojave Desert. The Granite Mountains represent the western-most range of the lyre snake (Trimorphodon biscutatus) and the ground snake (Sonora semiannulata), which are mostly Sonoran Desert species, and the southwestern-most extention of the southwestern black-headed snake (Tantilla hobartsmithi). The federally threatened desert tortoise (Gopherus agassizii), forages and burrows in the alluvial soils at the base of the range.

Many species are habitat generalists, such as the side-blotched lizard (Uta stansburiana) and coachwhip snakes (Masticophis flagellum). Others are restricted to specific habitats, such as the rocky outcrops inhabited by chuckwallas (Sauromalus obesus), or the wind-blown sand that accumulates at the base of the range, creating habitat for shovel-nosed snakes (Chionactis occipitalis) and fringe-toed lizards (Uma scoparia).

Lizards and snakes can be found in all habitat types in the Granite Mountains. At lower elevations adjacent to the bajadas, common species include western whiptails (Cnemidophorus tigris) and side-blotched lizards. Mid-elevation areas with larger rock outcrops supporting granitic boulder slope vegetation are typically inhabited by Great Basin collared lizards (Crotaphytus insularis) and speckled rattlesnakes (Crotalus mitchelli). At higher elevations, the boulder-strewn pinyon-juniper woodland is habitat for striped whipsnakes (Masticophis taeniatus), Gilbert’s skinks (Eumeces gilberti), and western fence lizards (Sceloporus occidentalis). Theses latter two species are examples of more widespread species that are similarly isolated in other Mojave Desert ranges.

Species typically inhabiting the cresosotebush scrub and mixed woody scrub of the lower bajada include: zebra-tailed lizards (Callisaurus draconoides), Mojave rattlesnakes (Crotalus scutulatus), western whiptails, side-blotched lizards, and sidewinders (Crotalus cerastes). Lizards that are common in the more diverse mixed woody and succulent scrub of the upper bajadas include: desert horned lizards (Phrynosoma platyrhinos), desert spiny lizards (Sceloporus magister), desert night lizards (Xantusia vigilis), gopher snakes (Pituophis melanleucus), western patch-nosed snakes (Salvadora hexalepis), and speckled rattlesnakes.

Riparian vegetation in the Granite Mountains varies from fairly open low-growing shrubs to densely-wooded thickets of trees and shrubs. In the lower, open, sandy washes zebra-tailed lizards are most abundant. Typically found in wash areas with dense shrub cover are western whiptails,side-blotched lizards, desert iguanas (Dipsosaurus dorsalis), and the long-tailed brush lizards (Urosaurus graciosus). In the mountain canyons where water courses are characterized by tall brushy vegetation and rocky terrain, Gilbert’s skink, striped whipsnake, and western fence lizard can be found.

Additional surveys are needed to obtain a comprehensive understanding of the herpetofauna of the Granite Mountains. Specifically, too few records of species such as the western blind snake (Leptotyphlops humilis), ground snake (Sonora semiannulata), and night snake (Hypsiglena torquata) have been made to draw any conclusions about their status. In addition, the high peaks, plateaus, and ridges of the Granite Mountains are relatively unexplored; other isolated species, such as ringneck snake (Diadophis punctatus), may occur there.

Birds
Bird Species List

The Granite Mountains hosts a diverse array of bird species throughout the year. The diverse floristic composition of the range and surrounding valleys, coupled with the relatively high number of seeps and springs, supports a resident community of about 30 species and over 100 regularly occurring migrants. The greatest diversity of birds occurs during the spring and fall migrations, which typically occur from March through May and August through October, with peaks in April and September. In general, occurrences slow down during summer months when high temperatures reduce activity. However, brief periods of activity may be observed at dawn and dusk, and areas around water often remain productive throughout the day. Winter months typically have the lowest species diversity, although the songs of the abundant White-crowned Sparrows fill the cold, crisp days with clear whistles and a series of buzzes and trills

A total of 159 bird species that have been recorded at the Granite Mountains. Of this total however, only 34 species are year-round residents. While many resident species, such as the Black-throated Sparrow and Cactus Wren, live in open desert scrub and are readily observable by visitors, others, such as the Mountain Quail, Juniper Titmouse, Mountain Chickadee, and Western Scrub Jay, remain at upper elevations in pinyon-juniper woodland and are seldom seen. A few, such as Bewick’s Wren and Crissal Thrasher, are commonly found near riparian areas. Twenty-seven bird species are seasonal residents that stay for prolonged periods to breed or overwinter at the Granite Mountains, but are not recorded here year-round. Summer residents include Scott’s Oriole, Ash-throated Flycatcher, Western Kingbird, Black-chinned Hummingbird and Common Nighthawk. Although White-crowned Sparrows are the most abundant winter resident, Dark-eyed Junko, Cooper’s Hawk, Prairie Falcon, Northern Flicker, and Townsend’s Solitare are also regularly observed. Seventy-five of the bird species recorded at the Granite Mountains are regularly occurring migrants, with a significant representation of hummingbirds, warblers, vireos, flycatchers, and sparrows.


Migrants are most commonly found near springs and seeps at the base of the mountain and along washes containing desert willow (Chilopsis linearis). During wet years some otherwise migratory species may breed at the Granite Mountains. Recent noteworthy vagrants recorded in Granite Cove include Prothonotary Warbler (Fall ’04), Northern Parula (Spring 06), Indigo Bunting (Spring ’06) and Rose-breasted Grossbeak (Spring ’06).

One of the greatest challenges in living in a desert system is maintaining a positive water balance during periods of high temperatures and low water availability. Recent research conducted at the center has examined the effects of water availability on the reproductive success in desert birds. Coe and Rotenberry (2003) found that breeding Black-throated Sparrows laid significantly larger clutches when supplemental water was made available relative to birds breeding in areas without supplemental water. Their results indicate that although Black-throated Sparrows can successfully reproduce and survive without drinking water, water availability can place limits on reproductive output.

Mammals
Mammal Species List

The Granite Mountains support 42 mammal species, including 8 bats, four squirrels, and 14 rodents. Most of the mammals found in the Granite Mountains are representative of those found throughout the Mojave Desert. Exceptions include the Brazilian free-tailed bat (Tadarida brasiliensis), desert shrew (Notiosorex deserti), and dusky-footed woodrat (Neotoma fuscipes), for which the only known occurrences in the East Mojave are within the Granite Mountains. Species on the borders of their distributions include: rock squirrels (Spermophilus variegates), reaching their western distributional boundary, Panamint chipmunks (Eutamias panamintinus), reaching their southern distributional boundary, and the spiny pocket mouse (Chaetodipus spinatus), reaching its northernwestern boundary in the Granite Mountains.

The wide range of habitats in the Granite Mountains support mammals that are habitat generalists as well as habitat specialists with restricted distributions. For example, kit foxes (Vulpes macrotis) and cactus mice (Peromyscus eremicus) may be found in multiple vegetation types and elevations, while ringtail cats (Bassariscus astutus) and pallid bats (Antrozous pallidus) are generally found only on rocky slopes, and desert kangaroo rats (Dipodomys deserti) and round-tailed ground squirrels (Spermophilus tereticaudus) only on sandy soils.

The rocky, mountainous areas of the Granite Mountains that support granitic boulder slope vegetation and pinyon-juniper woodland include a high diversity of species relative to the bajadas. Typical species include: California myotis (Myotis californicus) , big brown bat (Eptesicus fuscus), western pipistrelle (Pipistrellus hesperus), Brazilian free-tailed bat, black-tailed hare (Lepus californicus), desert cottontail (Sylvilagus audubonii), Panamint chipmunk (Tamias panamintinus), Botta pocket gopher (Thomomys bottae), long-tailed pocket mouse (Chaetodipus formosus), pinyon mouse (Peromyscus truei), white-tailed antelope squirrel (Ammospermophilus leucurus) , desert woodrat (Neotoma lepida) , and desert mountain sheep (Ovis canadensis). Species typically occurring in the bajadas are: black-tailed hare, desert cottontail, white-tailed antelope squirrel, Botta pocket gopher, deer mouse (Peromyscus maniculatus), southern grasshopper mouse (Onychomys torridus), desert woodrat, and coyote (Canis latrans) . Perennial surface water attracts a variety of mammals, but bats in particular are most commonly observed due to the greater abundance of insects in these areas.

Invertebrates
Invertebrate Species List

To date, five classes of arthropods representing 16 orders and at least 162 families have been identified in the Granite Mountains. Beetles, flies, and wasps make up the majority of the family diversity. Surveys have identified wasp, ant, beetle, and cricket species that are new to science, including: Cavernocymbium vetteri (Amaurobiidae), Physocyclus undescr. sp. (Pholcidae), Xeroheriades micheneri (Megachilidae), Perdita n. sp. nr. Arenaria (Andrenidae), Belomicrus n. sp. nr. sechi (Crabronidae), Psilus nr. Inaequalifrons (Diapriidae), Lariversius n. sp. (Tenebrionidae), Euparagia unidentata n. sp. (Vespidae). Given the minimal extent of invertebrate sampling, the discovery of these species not only suggests that the invertebrates of Granite Mountains are far from being fully documented, but that more species new to science await to be discovered. The lack of a representative species list, as well as basic information on habitat and environmental preferences, makes it impossible to make generalizations about invertebrate taxa in the region.

A few invertebrate surveys have been conducted in the Granites Mountains, but a single comprehensive survey spanning multiple seasons and elevations is lacking. Cyndra Dietz and Duane Conroy conducted a survey in the spring of 1982 in two locales of the Granite Mountains. The results from this survey comprise the majority of our invertebrate family list, but specimens remain to be identified to species. The Friends of the Entomology Research Museum conducted several 1-2 day surveys between 1996 and 2003. These specimens have been identified to species and comprise the majority of our invertebrate species list. Currently, Mark Ikeda and James des Lauriers are working on a collection of ants both in the larger Mojave National Preserve and in the Granite Mountains. Laurelin Evanhoe is conducting her graduate work on population genetics and community ecology of native bees in the east Mojave Desert. Her research will also contribute greatly to our list of bee species

For a subset of species from our species list Gregg Ballmer of UC Riverside and the Friends of the Entomology Research Museum provided some additional information on physiographic/physiognomic designations, host plants, and biogeography, summarized in Table 1. The following is a list of this subset of species by physiographic/physiognomic designation.

Bajada scrub – Boulder scrub

Hesperiidae (Skippers): Hesperopsis libya

Nymphalidae (Butterflies): Chlosyne californica

Lycaenidae (Gossamer-Winged Butterflies): Apodemia mormo deserti

Pieridae (White and Sulphur Butterflies): Eurema nicippe

Syrphidae (Hoverflies): Polybiomyia sayi

Tenebrionidae (Darkling beetles): Philolithus actuosus

Boulder scrub & Pinyon-juniper

Skippers: Heliopetes ericetorum

Lycaenidae (Gossamer-Winged Butterflies): Apodemia mormo mormo, Atlides halesus, Callophrys comstocki, Euphilotes enoptes dammersi, Plebejus acmon texanus, Plebejus lupini

Mantidae (Mantids): Litaneutria minor

Mydidae (flies): Rhaphiomidas acton

Nymphalidae (Butterflies): Euphydryas chalcedona kingstonensis, Chlosyne neumoegeni, Chlosyne leanira near alma

Pieridae (White and Sulphur Butterflies): Anthocharis sara thoosa

Saturniidae (Moths): Hemileuca neumoegeni

Scarabaeidae (Scarab beetles): Paracotalpa puncticollis *associated with juipers

Dunes

Mydidae (flies): Rhaphiomidas tarsalis

Polyphagidae (Sand Cockroaches): Arenivaga sp.

Tenebrionidae (Darkling beetles): Cryptoglossa muricata, Edrotes ventricosus

Vespidae (Hornets, Yellowjackets, Paper Wasps): Euparagia unidentata

Several Communities

Short-horned Grasshoppers: Anconia integra, Cibolacris parviceps

Apidae (Honey, bumble, euglossine bees): Apis mellifera

Asilidae (Robber flies): Efferia sp.(several species)

Hesperiidae (Skippers): Erynnis funeralis, Pyrgus albescens

Lycaenidae (Gossamer-winged butterflies): Strymon melinus pudica, Brephidium exile, Leptotes marina, Hemiargus ceraunus, Hemiargus isola alce

Mymaridae (wasps): Gonatocerus sp

Nymphalidae (Butterflies): Cynthia cardui

Papilionidae (Swallowtail butterfly): Papilio polyxenes coloro

Pieridae (White and Sulphur Butterflies): Pontia beckerii, Pontia protodice

Tenebrionidae (Darkling beetles): Eleodes armata, Philolithus actuosus

Vespidae (Hornets, Yellowjackets, Paper Wasps): Vespula pensylvanica