Eastern Mojave Vegetation
Tom Schweich
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Eastern Mojave Vegetation
| The Vegetation of Lobo Point and North Wild Horse Mesa, Mojave National Preserve, San Bernardino County, California. (Continued) |
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Tom Schweich |
Topics in this Article: Introduction Geography Geology Climate Methods Results Discussion Summary Literature Cited |
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DiscussionThe purpose of this section is to discuss the results of other researchers' work in eastern Mojave vegetation and related topics. | |
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Literature Cited:
Other articles:
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Yeaton et al. (1985) reported their study ecology of three Yucca species, the association of Joshua Tree (Yucca brevifolia), Mohave Yucca (Y. schidigera), and Blue Yucca (Y. baccata) in the eastern Mojave Desert. | |
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Literature Cited:
Locations: Lobo Point. Mid Hills. |
Applying the data of Yeaton et al. (1985) to Lobo Point (1400 m), I would predict dominance of Y. baccata over Y. schidigera. That is indeed the case. I would also predict presence of Y. brevifolia at Lobo Point. However, the nearest occurrence is along the Mid Hills ridge line, 6 km northwest at 1650 m elevation. The absence of Y. brevifolia on the southeast side of the Mid Hills ridge line remains a puzzle. | |
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Comstock, Cooper, and Ehleringer (1988) studied seasonal patterns of canopy development and carbon gain in nineteen warm desert shrub species. | |
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Literature Cited:
Locations: Great Basin Desert. Inyo Mountains. Little Thorne Mountains. Lobo Point. White Mountains. White Mountains. |
Bradley and Deacon (1967) described blackbush scrub as an ecotonal vegetation type in southern Nevada, at the transition from the Mojave Desert to the Great Basin Desert. There, blackbush scrub forms the ecotone between creosote bush scrub and basin sagebrush scrub (Trimble, 1989). Creosote bush scrub is found just to the south of and below Lobo Point. Basin sagebrush is found at 1600 m, just 3 km north of Lobo Point on the slopes of the Little Thorn Mountains. It appears that something like the ill-defined blackbush scrub also forms an ecotone between creosote bush and sagebrush at Lobo Point. This is in reverse order to that found in the White-Inyo Mountains, where Blackbush is found above the Sagebrush (Schoenherr, 1992). | |
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Literature Cited:
Locations: Beaver Dam Mountains. Beaver Dam Wash. Dixie Corridor. |
Habitat relationships of a Blackbrush community in southwestern Utah were studied by Callison and Brotherson (1985). On study sites located in the Dixie Corridor between the Beaver Dam Wash and the Beaver Dam Mountains, they found that Blackbrush (Coleogyne ramosissima) strongly dominated with an average relative density of 0.79. A small number of a few other shrubs were present: Ephedra nevadensis, Thamnosma montana, and Gutierezia microcephala. Yucca baccata and Y. brevifolia were also present in small numbers. Shrubs were found to be positively correlated with shallow, sandy soil. Nonwoody plants were found to be positively correlated with deeper, silty soils. Cryptogamic soil crusts were positively correlated with silt and nitrogen in the soil and therefore may play a role in increasing soil fertility. | |
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Locations: Gold Valley Ranch. Lobo Point. |
Blackbush (Coleogyne ramosissima) does not dominate at Lobo Point, occurring there with relative densities of 0.1 to 0.3. At most, Blackbush co-dominates with California Buckwheat (Eriogonum fasciculatum). There are a few sites in the eastern Mojave at which Blackbrush is found in high relative densities such as the 0.40-0.50 range. The highest relative density I have observed is 0.52, on Black Canyon Road north of Hole-in-the-Wall and almost to the turn-off to Gold Valley Ranch. This site is a gently sloping bajada with a relatively stable surface. In general, Blackbrush occupies the most stable sites, and the other shrubs are found in or along the watercourses. | |
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The species associated with Blackbush in the eastern Mojave are different from those reported by Bradley and Deacon (1967). Vasek and Barbour (1988) point out that the definition of blackbush scrub by species is problematic. However, a scrub of low dark shrubs that lies above the creosote bush and extends up into Joshua trees, junipers, and pinyons, occurs over much of the Mojave Desert. This scrub often has the appearance of blackbush scrub even when Blackbush is not present. | |
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Literature Cited:
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Lei and Walker (1997a, 1997b) and Lei (1997) reported their study of (1) classification and ordination of Coleogyne communities, (2) biotic and abiotic factors influencing the distribution of Coleogyne communities, and (3) germination response to temperature and water availability in Blackbrush in southern Nevada. | |
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Locations: Granite Mountains. Mid Hills. |
Cody (1986a) studied shrub spacing patterns at the Granite Mountains and in the Mid Hills. | |
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Literature Cited:
Locations: Granite Mountains. Mexican Water Spring. Mid Hills. New York Mountains. |
Cody and Thompson (1986) studied shrubs that are intermediate in morphology between Ericameria (Happlopappus) cooperi and E. (H.) linearifolius. One of their study sites is near Mexican Water Spring in the Mid Hills. Other nearby sites are in the New York Mountains and the Granite Mountains. Approximately one per 300 plants of the combined populations is intermediate in morphology. Cody and Thompson (1986) conclude that the intermediates are sterile hybrids of E. cooperi and E. linearifolius. | |
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Literature Cited:
Locations: Joshua Tree National Park. Mojave National Preserve. |
Phillips et al (1980) studied vegetational characteristics of two stands of Joshua tree woodland Joshua Tree National Monument. They found similar species to those in Mojave National Preserve, including codominance of Blackbrush (Coleogyne ramosissima) and California Buckwheat (Eriogonum fasciculatum) in one of their two transects. They also learned that much variation occurs in Joshua tree woodlands that seem visually similar. | |
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Locations: Cima. |
As reported in Vasek and Barbour (1988), Vasek and Rowlands (not published) measured vegetational characteristics of a Joshua tree woodland north of Cima. | |
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Locations: Columbia Mountain Quadrangle. Mid Hills Campground. Round Valley. |
I found no published studies of the Sagebrush Scrub in the Lobo Point area, only occasional references to the Round Valley Sagebrush assemblage, just north of the study area, in the Mid Hills, California 7.5 Minute Quadrangle and near the BLM's Mid Hills Campground. This assemblage extends south into the Columbia Mountain quadrangle between 1525 m to 1650 m elevation. My sampling transects, not reported here, show relative densities for Sagebrush commonly in the 0.70 to 0.80 range. | |
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Locations: Los Angeles. |
The distribution, autecology, synecology and economic use of pinyon pine have been summarized in many recent references; see, for example, Everett (1987). Much of the literature focuses on economic use and "management." This generally means improvement as cattle range, deer habitat for hunting, or increased rainfall runoff for storage in down stream reservoirs. Hurst (1977) points out " ... the pinyon-juniper type has been a very hospitable living area since the arrival of man. Because of this, pinyon-juniper stands are rich in archeological treasures -- a value not adequately recognized." Recreation other than hunting is rarely mentioned in the literature. This is important because the increasing population of the metropolitan Los Angeles area is causing increasing pressure on the eastern Mojave Desert for recreation. | |
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Bailey (1988) reported on his extensive study of single-needle pinyons whose natural ranges lie mainly in the Californias and the Great Basin. | |
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Locations: Caruthers Canyon. Clark Mountain. |
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Locations: New York Mountains. |
Hendrickson and Prigge (1975) discuss the near legendary Rocky Mountain White Fir (Abies concolor var. concolor) grove in the New York Mountains. | |
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Sawyer and Keeler-Wolf (1995) published an analysis of California vegetation, defining series descriptive of common and rare parts of which I intend to review when synthesizing plant associations and, perhaps, a new series based upon my work on the Eastern Mojave. | |
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Date and time this article was prepared: 11/3/2024 5:32:37 PM |
