Chapter 3 - Natural Resources - Marine Corps Base Camp Pendleton

MCB Camp Pendleton, California
to the vernal pools that the Riverside fairy shrimp inhabit. These measures are published as
programmatic instructions for users and residents of the Base via Camp Pendleton’s Base
Order P3500.1N (Range and Training Regulations). Management details, survey
information, etc., for the Riverside fairy shrimp are located in Appendix F, Section F.14.
DISTRIBUTION
Global
The Riverside fairy shrimp’s total range extends from coastal southern California south to
northwestern Baja California, Mexico (USFWS, 2000c). The 3 August 1993, listing rule
stated that Riverside fairy shrimp were known to inhabit 9 vernal pool complexes within
Riverside, Orange, and San Diego counties, and Baja Mexico, including four vernal pools
in Riverside County, one population in Orange County, two areas in San Diego County,
and two locations in Baja California, Mexico. However, it is now thought the Murrieta
Golf Course (Riverside County) location was likely already lost to development prior to
listing. In addition, the one population in Orange County referenced in the listing rule has
never been confirmed. Thus, at listing, it is likely that there were only three extant
occurrences of Riverside fairy shrimp known from Riverside County, two occurrences
known from San Diego County, and two occurrences known from Mexico (i.e., 5 in the
United States and 2 in Mexico).
FIGURE 3-33.
REGIONAL VERNAL POOL LOCATIONS
(FIGURE SOURCE: USFWS 2008H)
Since listing, as many as 52
additional occupied complexes have
been identified, including one manmade
complex at Johnson Ranch,
however, about 9 of the total 57
complexes are known to have been
extirpated, and the USFWS is
unsure whether the species persists
in 3 other complexes; hence, there
are currently 45 known occupied
vernal pool complexes
(approximately 200 occupied pools)
within the U.S., which includes the
man-made complex at Johnson
Ranch (USFWS 2008h). All but one
of these additional occurrences were
likely in existence at the time the
species was listed, but had not been
identified, and therefore were not
included in the analyses that led to
the listing of the species. The
species has also been introduced
into restored/enhanced vernal pools
as part of vernal pool restoration
projects: approximately 8 acres of
habitat has been restored since
3-68 Chapter 3 – Natural Resources