Soil Ecology and Research Group
last update December 10, 2002
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Soil Ecology and Research Group last update December 10, 2002 |
VEGETATION SURVEYS WITHIN THE
MOJAVE DESERT OFF-HIGHWAY VEHICLE OPEN AREAS (BARSTOW RESOURCE AREA)
SUMMARY
The Soil Ecology and Restoration Group in San Diego, California was subcontracted by Anteon Corporation during early spring of 2002 to complete plant surveys within five Off-Highway Vehicle (OHV) Open Areas managed by the Bureau of Land Management (BLM) within the Barstow Resource Area. The five open areas surveyed were: Stoddard Valley, Rasor, Dumont Dunes, Johnson Valley, and El Mirage. All work was completed during the months of May and June 2002. Major objectives included surveying for Special Status Plant Species (SSPS) and Unusual Plant Assemblages (UPA) within the open areas. If a SSPS was located, additional surveying was to be completed to determine if the occurrence was being impacted by OHV activity and management recommendations were to be made. No SSPS or previously undiscovered UPA was located within the five open areas. The UPAs known to occur within the open areas were surveyed for potential negative impacts. No damaging impacts were determined to exist.
Very few annual plant species germinated or were identifiable in the Mojave Desert during the growing season of 2002. This was due to the lack of precipitation during the fall and winter of 2001/2002. We strongly recommend that future plant surveys of the five open areas be repeated following an average rainfall season since many of the SSPS potentially supported by habitats within the open areas are annual species.
INTRODUCTION
Five OHV open areas are located within the BLM Barstow district: Stoddard Valley, Rasor, Dumont Dunes, Johnson Valley, and El Mirage. These open areas vary greatly in size and habitat diversity. During the months of May and June 2002, the Soil Ecology and Restoration Group used a two-person crew to conduct vegetation surveys within the five OHV open areas. Research completed previous to the commencement of field work included reading through all available BLM Management Plans and Environmental Assessments for the open areas as well as the amended California Desert Conservation Area Plan and its updated appendices. In addition, species accounts provided by the BLM for plants known or thought to exist within the open areas were used to determine habitat requirements and known historical occurrence locations. Maps displaying delineated occurrences for Special Status Plant Species (SSPS) and Unusual Plant Assemblages (UPAs) within the Barstow Resource Area were consulted at the BLM Barstow field office. With all research completed, a survey plan was designed for each open area. The plans focused on relocating historical occurrences for SSPS, conducting general plant surveys for SSPS, and surveying potential high impact areas such as OHV staging areas and access road junctions.
METHODS
During field surveying, data was collected while slowly driving through the five open areas on accessible and safe 4-wheel drive roads. The open areas were navigated using BLM Desert Access Guides, United States Geological Survey (USGS) 7.5 minute topographic quadrangle maps, odometer logs, and a hand-held GPS unit. General plant communities were noted and if any changes in vegetation or unidentifiable plants were located, the surveyors stopped and conducted a general plant survey, staying within a one-mile radius of the vehicle. Plant photos were taken at most stops. Central survey locations were recorded as UTM coordinates collected on a hand-held GPS unit. Any unknown plants with adequate plant material available were collected to be keyed out. This task proved challenging during 2002 as very few annual plant species germinated and last year’s annuals had inadequate flowering or fruiting parts for positive species identification.
General plant surveys were conducted as relévé, or “wandering”, surveys from the road and parked vehicle. Surveyors continued to document vegetation diversity as long as new species were located. At the point when no new species were being identified, the general survey for the area was considered complete. The protocol for locating Mimulus mohavensis or any other BLM SSPS was to involve more detailed surveying, including collection of the occurrence polygon size and location using GPS, individual plant numbers, and phenology data. In addition, photographs of the species would be taken and a California Natural Diversity Database form would be completed for each occurrence.
Because the field surveying began relatively late in the season to catch many desert plant species in their reproductive phase, Stoddard Valley open area, where Mimulus mohavensis is known to occur, was given surveying priority. This species is the only SSPS occurrence presently known within a Barstow Resource Area OHV open area.
The following lists include records for plants of interest documented from USGS 7.5 minute topographic quadrangle maps at the BLM Barstow field office (occurrences were hand-marked) and maps included in the amended California Desert Conservation Area Plan (1980):
Stoddard Valley:
Astragalus mohavensis var. mohavensis (SE- West Ord Mtns)
Chorizanthe spinosa (SW)
Cymopterus deserticola
Eriophyllum mohavense (N- along Barstow Rd.)
Mimulus mohavensis (N- along Barstow Rd., E of Airway Beacon and W-
SE of Hodge), Psorothamnus arborescens var. arborescens (N- along Barstow Rd.)
Sclerocactus polyancistrus (W)
Rasor Open Area:
Desert Willow UPA (within and W/SW)
Dumont Dunes:
Centaurium exaltatum (N) (low occurrence potential)
Galium hilendiae ssp. kingstonense (E)
Linanthus arenicola (SE from open area)
Penstemon stephensii (E)
Johnson Valley:
Arabis shockleyi (S)
Calochortus striatus (S)
Chamaesyce platysperma (NE- NE of Melville Lake, W- Old Woman Springs)
Desert Riparian UPA (W to SW)
Desert Willow UPA (W to SW)
Echinocereus engelmannii (S)
Erigeron parishii (SW- Rattlesnake Cyn just SE from Rattlesnake Spring)
Fry Mountain Ancient Mojave Yucca (Yucca brevifolia) Clone UPA (NW-Fry
Mtns) Johnson Valley/Lucerne Valley Creosote bush (Larrea tridentata)
clone UPA (within and NW-just SE of Soggy Lake)
Puccinellia parishii (S)
El Mirage:
Chorizanthe spinosa (E)
Cymopterus deserticola (N)
Sclerocactus polyancistrus (SE)
Western Mojave Desert Mojave Saltbush (Atriplex spinifera) Assemblage
(just N)
Table 1 summarizes the lists above and includes plant species of interest that were found to have some potential of occurring within the open areas. This list was created following pre-survey research using BLM resources.
Table 1.
Uncommon, Rare, and BLM Special Status plant species with a relatively high
potential to exist within the five open areas.
Plant Species (scientific name) Penstemon stephensii |
Status Rare Included on BLM maps BLM Special Status Plant Species BLM Special Status Plant Species Uncommon BLM Special Status Plant Species Included on BLM maps BLM Special Status Plant Species BLM Special Status Plant Species Rare BLM Special Status Plant Species; USFWS Species of Concern BLM Special Status Plant Species BLM Special Status Plant Species Uncommon Uncommon BLM Special Status Plant Species Uncommon |
Stoddard Valley Open Area:
Surveyors: Amy Rusev, Michelle Cloud-Hughes
Dates of survey: 14-16 May 2002
Major objectives:
A top priority for the surveying of Stoddard Valley Open Area was to revisit and survey known historical occurrence locations of Mimulus mohavensis (MIMO) in order to confirm germination and to gain familiarity with MIMO’s habitat and associated plant species. Regardless of whether or not the plant was relocated in known historical locations, general surveys were conducted for MIMO within appropriate habitat supported by the open area (including drainages “upstream” from the historical occurrence sites). General surveys for Chorizanthe spinosa, Eriophyllum mohavensis, Psorothamnus arborescens var. arborescens, and Sclerocactus polyancistrus were performed in creosote-bush scrub habitat. Surveys were conducted for Astragalus mohavensis var. mohavensis on any limestone substrate discovered. Surveys for Cymopterus deserticola were performed on sandy flats and slopes within general desert habitat. General plant surveys were completed at random locations throughout the open area (as well as target locations where changes in dominant plant communities were apparent). General plant surveys defined the representative habitat-types within the open area. High-impact sites such as access road junctions and staging areas were surveyed for presence of Special Status Plant Species. Management recommendations were not necessary.
Rasor Open Area:
Surveyors: Amy Rusev, Michelle Cloud-Hughes
Dates of survey: 3-4 June 2002
Major objectives:
Rasor Open Area’s amended western boundary was monitored. The new boundary was implemented to exclude most of the Desert Willow UPA from the open area (both sides of Basin Road were checked to see if the new boundary was effectively excluding OHV activities from continuing west). Plant surveying priority was given to sites along shared borders within the open areas; Afton Canyon Natural Area lies to the west, Soda Springs ACEC lies to the north, and the East Mojave National Scenic Area lies to the east. The contingent areas on all sides of the open area contain undisturbed habitat and should not be negatively impacted by OHV activities. Random general surveys were conducted throughout the open area (as well as target locations where changes in dominant plant communities were apparent). General plant surveys defined the representative habitat-types within the open area. High-impact sites such as access road junctions and staging areas were surveyed for presence of Special Status Plant Species. Management recommendations were not necessary. No SSPS were currently known to exist within Rasor Open Area or in nearby surrounding areas.
Dumont Dunes Open Area:
Surveyors: Amy Rusev, Michelle Cloud-Hughes
Dates of survey: 5 June 2002
Major objectives:
Dumont Dunes Open Area is surrounded by Ibex Wilderness (northwest), Kingston Range Wilderness (north/northeast), and Salt Creek Hills Area of Critical Environmental Concern (south). If accessibility allowed, surveying priority was given to these shared border areas (road access was extremely limiting). The contingent areas on all sides of the open area contain undisturbed habitat and should not be negatively impacted by OHV activities. Surveys were conducted for Centaurium exaltatum (Centaurium namophilum var. namophilum- USFWS threatened is now recognized as C. exaltatum) if any moist, alkaline scrub habitat was located. Surveys for Galium hilendiae ssp. kingstonense and Penstemon stephensii were performed in rocky areas within creosote-bush scrub habitat. Surveys were conducted for Linanthus arenicola within saline flats. Random general surveys were completed throughout the open area (as well as target locations where changes in dominant plant communities were apparent). General plant surveys defined the representative habitat-types within the open area. High-impact sites such as access road junctions and staging areas were surveyed for presence of Special Status Plant Species. Management recommendations were not necessary.
Johnson Valley Open Area:
Surveyors: Amy Rusev, Carrie Charlton
Dates of survey: 11-13 June 2002
Major objectives:
Johnson Valley Open Area supports large sections of the Creosote Ring Unusual Plant Assemblage (UPA) and the Yucca Ring UPA. Two Areas of Critical Environmental Concern (ACEC) have been designated to protect some of the Creosote and Yucca Ring UPAs. The ACECs within the open area were partially surveyed for OHV impacts. Occurrences of clones found beyond the ACECs were documented. A historical occurrence of Chamaesyce platysperma is known from within the open area (however, this species has not been found in California since 1914). This occurrence location and additional appropriate habitat within the open area was surveyed for the plant species. Surveys were conducted for Arabis shockleyi where limestone or quartzite substrate was discovered. Calochortus striatus was surveyed for in moist creosote-bush scrub. Surveys for Echinocereus engelmannii were performed in dry desert habitat-types. Erigeron parishii was surveyed for within rocky creosote-bush scrub habitat or on limestone substrate. Random general surveys were conducted throughout the open area (as well as target locations where changes in dominant plant communities were apparent). General plant surveys defined the representative habitat-types within the open area. High-impact sites such as access road junctions and staging areas were surveyed for presence of Special Status Plant Species. Management recommendations were not necessary.
El Mirage Open Area:
Surveyors: Amy Rusev, Carrie Charlton
Dates of survey: 14 June 2002
Major objectives:
A section of the Mojave Desert Mojave Saltbush Unusual Plant Assemblage occurs within the open area. This area was partially surveyed for OHV impacts. Surveys were conducted for Chorizanthe spinosa and Sclerocactus polyancistrus within creosote-bush scrub habitat. Cymopterus deserticola was surveyed for on sandy flats and slopes within the open area. Random general surveys were completed throughout the open area (as well as target locations where changes in dominant plant communities were apparent). General plant surveys defined the representative habitat-types within the open area. The borders of the dry lakebed (OHV high-impact area) were surveyed for presence of any Special Status Plant Species. High-impact sites such as access road junctions and staging areas were surveyed for presence of Special Status Plant Species. Management recommendations were not necessary.
RESULTS
No occurrences of BLM Special Status Plant Species were located within any of the five open areas. During the first field surveying trip to Stoddard Valley Open Area, a standard procedure was designed to make future field surveying trips more efficient and to keep data collection accurate and organized. General plant lists were generated in key locations representative of the greater habitat supported within the open areas. Photographs were taken of the areas where general plant surveys were conducted and UTM coordinates were recorded using a hand-held GPS unit. Known UPAs located within the open areas were surveyed for negative impacts. The UPAs were determined to be generally undisturbed. Borders of the open areas shared with Wilderness or Areas of Critical Environmental Concern (ACEC) were surveyed when possible for OHV disturbance. The OHV impacts were found to be well-contained within the designated open areas.
Figures 1-5 identify the spring 2002 vegetation surveying sites within the five OHV open areas. Tables 2-6 provide comprehensive plant lists for the five OHV open areas. Tables and Figures within Appendices A-E present detailed survey results for the open areas (Appendix A-Stoddard Valley Open Area, Appendix B-Rasor Open Area, Appendix C-Dumont Dunes Open Area, Appendix D-Johnson Valley Open Area, and Appendix E-El Mirage Open Area).
(click for full size)
Figure 1. Stoddard Valley Open Area map
(click for full size)
Figure 2. Rasor Open Area map
(click for full size)
Figure 3. Dumont Dunes Open Area map.
(click for full size)
Figure 4. Johnson Valley Open Area map.
(click for full size)
Figure 5. El Mirage Open Area map.
Table 2.
Comprehensive plant list for Stoddard Valley Open Area.
| Scientific Name | Common Name | Status |
| Abronia sp. Acacia greggii Acamptopappus sphaerocephalus var. hirellus Adenophyllum cooperi Ambrosia dumosa Asclepias sp. Atriplex canescens Atriplex confertifolia Atriplex hymenelytra Atriplex polycarpa Chamaesyce sp. Chorizanthe brevicornu var. brevicornu Chorizanthe rigida Cryptantha intermedia Curcurbita palmata Ephedra funerea Ephedra trifurca Ephedra viridis Eriogonum deflexum var. deflexum Eriogonum fasciculatum var. polifolium Eriogonum inflatum Eriogonum mohavense Eriogonum nidularium Hymenoclea salsola Krameria erecta Larrea tridentata Lepidium fremontii var. fremontii Lycium andersonii Mirabilis sp. Opuntia basilaris var. basilaris Opuntia bigelovii Opuntia ramosissima Pholisma arenarium Psorothamnus arborescens var. arborescens Salazaria mexicana Schismus barbatus* Senna armata Sphaeralcea ambigua Stanleya sp. Stephanomeria exigua ssp. exigua Thamnosma montana Xylorhiza tortifolia Yucca schidigera |
sand verbena catclaw goldenhead Cooper dyssodia burro-weed milkweed fourwing saltbush spiny saltbush desert holly allscale prostrate spurge brittle spineflower spiny-herb cryptantha coyote melon Death Valley ephedra ephedra, mormon tea green ephedra flat-topped buckwheat California buckwheat desert trumpet western Mojave buckwheat birdnest buckwheat cheesebush Pima rhatany, purple heather creosote bush peppergrass, pepperwort box thorn four o’clock beavertail cactus teddy-bear cholla pencil cactus dune food Mojave indigo bush bladder sage Mediterranean grass spiny senna apricot mallow prince’s plume stephanomeria turpentine-broom Mojave-aster Mojave yucca |
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* non-native species
Table 3.
Comprehensive plant list for Rasor Open Area.
| Scientific Name | Common Name | Status |
| Ambrosia dumosa Atriplex canescens Atriplex hymenelytra Atriplex polycarpa Bebbia juncea var. aspera Chamaesyce polycarpa Chamaesyce sp. Chilopsis linearis Chorizanthe brevicornu var. brevicornu Chorizanthe rigida Croton californicus Cryptantha intermedia Encelia farinosa Ephedra californica Ephedra sp. Ephedra trifurca Hymenoclea salsola Isocoma acradenia Larrea tridentata Oenothera deltoides Opuntia basilaris var. basilaris Opuntia bigelovii Petalonyx thurberi ssp. thurberi Phoradendron californicum Polypogon monspeliensis* Prosopis glandulosa Psathyrotes ramosissima Salsola tragus* Tamarix sp.* Tidestromia oblongifolia Tiquilia plicata |
burro-weed fourwing saltbush desert holly allscale sweetbush prostrate spurge prostrate spurge desert willow brittle spineflower spiny-herb croton cryptantha brittlebush desert tea ephedra, mormon tea ephedra, mormon tea cheesebush goldenbush creosote bush devil’s lantern, basket evening primrose beavertail cactus teddy-bear cholla sandpaper plant desert mistletoe annual beard grass honey mesquite turtleback Russian thistle, tumbleweed tamarisk, saltcedar Arizona honeysweet fanleaf crinklemat |
* non-native species
Table 4.
Comprehensive plant list for Dumont Dunes Open Area.
| Scientific Name | Common Name | Status |
| Ambrosia dumosa Atriplex hymenelytra Atriplex polycarpa Carex sp. Chamaesyce sp. Chorizanthe brevicornu var. brevicornu Chorizanthe rigida Cryptantha intermedia Distichlis spicata Heliotropium curassavicum Hymenoclea salsola Larrea tridentata Oenothera deltoides Polypogon monspeliensis* Prosopis glandulosa Salsola tragus* Suaeda moquinii Tamarix ramosissima |
burro-weed desert holly allscale sedge prostrate spurge brittle spineflower spiny-herb cryptantha saltgrass heliotrope cheesebush creosote bush devil’s lantern, basket evening primrose annual beard grass honey mesquite Russian thistle, tumbleweed bush seepweed tamarisk, saltcedar |
Table 5.
Comprehensive plant list for Johnson Valley Open Area.
| Scientific Name | Common Name | Status |
| Achnatherum hymenoides Achnatherum speciosum Ambrosia dumosa Astragalus lentiginosus var. variabilis Atriplex canescens Atriplex confertifolia Atriplex lentiformis var. torreyi Atriplex polycarpa Brickellia incana Chorizanthe rigida Croton californicus Cryptantha intermedia Echinocactus polycephalus var. polycephalus Encelia farinosa Ephedra nevadensis Ephedra sp. Eriogonum fasciculatum var. polifolium Eriogonum inflatum var. inflatum Eriogonum sp. (annual) Hymenoclea salsola Isomeris arborea Krameria parviflora Larrea tridentata Larrea tridentata (creosote ring clones present) Lepidium fremontii var. fremontii Lotus purshianus var. purshianus Oenothera deltoides Opuntia basilaris var. basilaris Opuntia bigelovii Opuntia ramosissima Oxytheca perfoliata Psorothamnus fremontii var. fremontii Psorothamnus polydenius Salazaria mexicana Salsola tragus* Senna armata Stanleya pinnata var. pinnata Stephanomeria exigua var. exigua Suaeda moquinii Thamnosma montana Tiquilia plicata Yucca schidigera Yucca schidigera (yucca clone rings present nearby) |
indian ricegrass desert needlegrass burro-weed freckled milkvetch fourwing saltbush spiny saltbush big saltbush allscale wooly brickellia spiny-herb croton cryptantha clustered barrel cactus brittlebush ephedra, mormon tea ephedra, mormon tea California buckwheat desert trumpet buckwheat cheesebush bladderpod Pima rhatany, purple heather creosote bush creosote bush peppergrass, pepperwort Spanish clover/lotus devil’s lantern, basket evening primrose beavertail cactus teddy-bear cholla pencil cactus oxytheca Fremont indigo-bush psorothamnus bladder sage Russian thistle, tumbleweed spiny senna prince’s plume stephanomeria bush seepweed turpentine-broom fanleaf crinklemat Mojave yucca Mojave yucca |
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* non-native species
Table 6.
Comprehensive plant list for El Mirage Open Area.
| Scientific Name | Common Name | Status |
| Achnatherum hymenoides Achnatherum speciosum Ambrosia dumosa Atriplex confertifolia Atriplex parryi Atriplex polycarpa Chorizanthe rigida Chrysothamnus sp. Echinocactus polycephalus var. polycephalus Ephedra nevadensis Ephedra sp. Eriogonum fasciculatum var. polifolium Eriogonum inflatum var. inflatum Hymenoclea salsola Krascheninnikovia lanata Larrea tridentata Larrea tridentata (some small rings present) Lycium andersonii Opuntia bigelovii Psorothamnus spinosus Salazaria mexicana Salsola tragus* Suaeda moquinii Tamarix chinensis* Tetrademia sp. Yucca brevifolia Yucca schidigera |
indian ricegrass desert needlegrass burro-weed spiny saltbush Parry’s salbush allscale spiny-herb rabbitbrush clustered barrel cactus ephedra, mormon tea ephedra, mormon tea California buckwheat desert trumpet cheesebush winter fat creosote bush creosote bush boxthorn teddy-bear cholla smoke tree bladder sage Russian thistle, tumbleweed bush seepweed tamarisk, saltcedar cotton-thorn, horsebrush Joshua tree Mojave yucca |
UPA |
* non-native species
CONCLUSIONS
No Special Status Plant Species (SSPS) were located within any of the five Barstow Resource Area OHV Open Areas. High-impact sites were not found to be currently threatening any sensitive plant populations or sensitive habitat. We recommend that additional surveys be conducted next year if precipitation increases through this next season. Very few annual plant species were identifiable. Again, we believe this to be related to the lack of precipitation preceding this growing season. In all areas, general plant lists were completed that are fairly representative of the flora found within the five OHV open areas surveyed during May and June of 2002.
Three uncommon plant species were located within Stoddard Valley Open Area: Eriogonum mohavense, Pholisma arenarium and Psorothamnus arborescens var. arborescens. No Mimulus mohavensis was relocated within Stoddard Valley Open Area at the historical occurrence locations. The minimal amount of precipitation received throughout winter of 2001/2002 may have reduced this species germination. Because this plant is known to occur within the open area, we highly recommend that historic sites are revisited and general surveys are conducted following a normal precipitation season.
DISCUSSION AND RECOMMENDATIONS
Conducting the five Barstow Resource Area OHV Open Area vegetation surveys following a year of average precipitation is strongly recommended. The desert annual plant species are extremely sensitive to moisture levels and germination can significantly decrease with insufficient precipitation. This climatic limiting factor is relevant to the OHV Open Area vegetation surveys because many of the Special Status Plant Species (SSPS) known or suspected to occur within the open areas are annual species.
Thorough surveying of the five OHV Open Areas for occurrences of SSPS and Unusual Plant Assemblages would require a significant amount of time in the field and a larger crew. BLM species accounts and associated literature references for SSPS potentially occurring in the OHV Open Areas should give sufficient background information for planning future surveys. Aerial photographs are ideal for targeting SSPS habitats within the open areas. A survey plan could be recreated that focused on targeting sites most likely to support SSPS and sensitive habitats regardless of their locations within the open areas. If time permits, priority plant inventory locations should be identified based upon high species diversity, rare substrates, and areas where special management concerns may be warranted. Due to the rugged nature of the terrain and the lack of safe vehicle accessibility throughout much of the open areas, long distance hiking would be required to complete exhaustive vegetation surveys. The open areas are very large in size and would require multiple surveying crews in order to complete vegetation surveys during a single spring season of any year.
