Audubon Kern River
Preserve protects part of the South Fork Kern River, a tributary of
the Kern River. During high water years part of the preserve now
rests under Isabella Reservoir, an artificial lake dedicated in 1953
for the purpose of irrigation and flood control for the southern San
The Kern River Valley is
a relatively flat valley located in the southern Sierra Nevada at an
elevation of 2300’ to 3500’. There are four major sections of the
Kern valley; South Fork, Weldon Valley, North Fork, and Hot Springs
Valley with many upslope hamlets surrounding these areas.
The South Fork Valley is
an alluvial valley ranging from 2600’-3300’ in elevation and is
filled with mostly granitic sediment from the eastern edge of the
Kern Plateau and the western Scodie Mountains. The topography of the
Kern River Preserve is gently sloped along the three miles of river
channel with relatively steep slopes along its northern mountainous
edge. Elevations on the preserve range from 2611’ to 4265’.
The South Fork Kern River Valley is
located in a watershed at the intersection of three of North
America’s ten floristic provinces: 1) Californian Floristic
Province, 2) Mojave Subprovince of the Sonoran Desert Floristic
Province, 3) Great Basin Desert Floristic Province. This assemblage
is unique to all of North America.
The South Fork Kern River supports
one of the finest and most defensible Great Valley cottonwood-willow
forests remaining in California. This forest stand is found on the
river from its point of departure from the Sequoia National Forest
to it terminus at Isabella Reservoir, a distance of approximately
13.5 river miles. Surrounding the riparian forest, are freshwater
marshes, meadows, pasture, cropland and uplands which connect to
vast areas of public land managed by the U.S. Forest Service and
Bureau of Land Management. The two agencies manage approximately 85%
of the 983 square mile watershed, with approximately 60% in
designated Wilderness. Furthermore, in the upper watershed, the 72.5
miles of the South Fork Kern River is protected by Wild and Scenic
The South Fork Kern River Valley is one of five initial
locations designated as a Globally Important Bird Areas by the
American Birding Association as well as a California Riparian
Habitat Joint Venture Flagship Projects.
The South Fork Kern River floodplain supports the largest
contiguous Great Valley Cottonwood Riparian Forest remaining in
There are no permanent dams on the South Fork Kern River along
its entire 86 mile length, above and through the project area.
The hydrological integrity of the river system is largely intact
and potentially defensible.
Invasive exotic species such as salt cedar, Russian-olive and
giant cane, dominate most southwestern riparian areas. However,
these species comprise less than 0.1% of the understory cover on
the South Fork Kern.
There are 407 acres of freshwater marshes and ponds that support
what may be one of California's largest populations of
southern Pacific pond turtle, a species of special concern in
52 critical elements being tracked by the California Natural
Diversity Database are found within the project area.
The area supports California's second-largest breeding
population of the state endangered Yellow-billed Cuckoo,
approximately one-third of the state population.
It also supports one of the largest breeding populations of the
federally endangered Southwestern Willow Flycatcher, approximately
29 pairs in 1996. This area serves as a core population for
The Summer Tanager is listed as a Species of Special Concern.
Approximately 30 to 40 pairs nest in the project area, the
state's largest population.
The Kern Red-winged Blackbird, an endemic subspecies, is found
only within the project area.
The South Fork Kern River riparian corridor provides summer
breeding habitat for over 50 species of
neotropical migrants that migrate to
California from Central and South America.
Sierra Nevada mountain regions can be viewed from the Kern River Preserve:
Kern Plateau, Scodie Mountains, Piute Mountains, Breckenridge
Mountain with the Greenhorn Mountains visible from the western
edge of the Preserve.
About Audubon Kern River Preserve
The Kern River Preserve is managed by
Audubon California for the preservation of one of California’s
largest contiguous cottonwood-willow riparian forests and the
wildlife it supports.
Audubon Kern River Preserve supporters provide financial and volunteer support for Preserve outreach, education, wildlife habitat protection & stewardship.