Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton

MCB Camp Pendleton, California
3.2.2.1. Vegetation Communities on Camp Pendleton
Vegetation distribution is primarily determined by climate, available moisture and soil
nutrients. Thus rainfall, temperature, soil type, topographic position, and elevation are all
important predictors of vegetation. All of these vary substantially on Base because of its
coastal location, diverse geology, and pronounced topography. Elevation on Base ranges
from sea level to 3,189 ft. Precipitation is lowest at the coast, around 10 inches average,
increasing to the east to a high of 24 inches near Case Springs. Most rain, 70%, falls from
February to March. Temperature varies from the low 100’s ◦ F in summer to just below
freezing in some areas during the winter, with mean temperature decreasing with elevation
(Zedler et al. 1997).
The coastal communities receive the lowest average rainfall, however, they benefit from
frequent fog and the moderating influence of the ocean, which reduces heat and moisture
stress during the summer. Along the immediate beach a unique set of species making up
the southern foredune community occupies the actively moving sand dunes (two locations).
Salt marsh is found where low topography combines with freshwater inflow and tidal
influence to support salt marsh and brackish marsh. On the stable drier soils along the coast
there are CSS-covered foothills, and a mixture of native and non-native grasslands in the
central valleys. Chaparral is found in the higher foothills, back ranges and open woodlands
along the peaks (Zedler et al. 1997).
3.2.2.2. Rare and Sensitive Plants
The first comprehensive botanical survey on Camp Pendleton was completed in 1986.
Since then, more than 10 surveys for rare and endangered plants have been conducted on
Base. Some of these surveys were conducted basewide, while others focused on selected
portions of the Base or specific plants. Surveys focusing on rare and sensitive plants were
conducted in: 1987 (PSBS 1987), 1988 (PSBS 1988), 1990 (PSBS 1990), 1993-1996
(Dudek & Associates 1994, 1996; Zedler & Bliss 1993), 1997 (RECON 1999) and 2000
(Tierra Data Systems 2000a). Since 2001, rare plant surveys have become more speciesspecific,
with as many as three separate surveys conducted in any one year. RECON,
AMEC, EDAW, North State Resources, and Dudek have completed rare plant surveys; San
Diego State University students working for SDSU’s Soil Ecology Restoration Group
(SERG), under professor guidance, have also supported some of these survey efforts. The
number and intensity of rare plant surveys are dependent upon annual funding (Lucas pers.
comm. 2008).
As a result of these surveys, a total of 39 sensitive plant species have been located on Camp
Pendleton including one new species, Camp Pendleton button-celery (Eryngium
pendletonense), and two species whose locations represented a 45-mile (Brand’s phacelia,
Phacelia stellaris) and a 300-mile (La Purisima viguiera, aka Viguiera purissimae
Brandegee) extension of their known range. Also these surveys specifically looked for
other federal and State listed plant species that were known to occur in the region,
including Encinitas baccharis (Baccharis vanessae), San Diego ambrosia (Ambrosia
pumila) and San Diego thorn-mint (Acanthomintha ilicifolia), but to date have not been
identified on Camp Pendleton. The Base continues to look for and document occurrences
of rare plants through basewide and project-level survey efforts.
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