The coordinates will take you to a parking area on Cook
Lane.
On the east side of Cook Lane you will find a picnic area with
tables and a seasonal "porta-potty" (spring months only).
On the west side of Cook Lane you will find a trail head for a self
guided nature trail.
The picnic area and nature trail are the only
areas in the preserve that are open to the public. Dogs are not
permitted along the nature trail.
Smoking is not permitted within the
preserve.
Jepson Prairie Preserve is the premier, and one of the few
remaining, claypan vernal pool habitats and native bunchgrass
prairies in California. Located 10 miles south of Dixon,
California, this 1,566 acre site is an island of remnant natural
prairie in a wide alluvial floodplain used primarily for
agriculture.
Jepson Prairie was spared from the plow and land development
because of the nature of its soils. These soils originated 15 miles
to the northwest from the wreckage of sedimentary rock called the
Vaca Mountains, which were uplifted from the sea floor as a result
of the collision of two of the earth's tectonic plates. The Vaca
Mountain sandstones, over tens of thousands of years, weathered
into sands, silts and clays.
Ancient watercourses, time and rainfall have moved and sorted these
particles of soil into a vast alluvial fan with a dense clay zone
beneath its surface. It is this water impermeable "claypan" and
infertile soils to which Jepson Prairie owes its vernal pools,
playa lakes and ultimately its preservation.
Vernal pools are temporary bodies of water formed when an
impermeable layer of soil prevents ground water seepage and traps
winter rain in shallow pools. A vernal pool larger than one acre is
called a playa lake. The largest of these lakes within the Jepson
Prairie Reserve is the 93 acre Olcott Lake. Vernal pools host
plants and animals during a brief lifecycle that ends when the
pools evaporate and the land becomes arid.
Mima-mounds (pronounced my-ma) are another curious feature of
the Jepson Prairie Preserve. Humps or bumps of sandy soil, this
type of landform occurs in western North America from Alaska to
Mexico. Here, the cover vegetation on the mounds is mostly
comprised of species not native to California, North America or
even the western hemisphere. It is this higher, drier ground where
native species cannot compete with the introduced types. Vegetation
native to this area thrives in the flooded conditions of the vernal
pools and swales around the bases of the mounds.
The preserve provides critical habitat for 400 species of
plants, including 15 rare and endangered species. Many animal
species found on site are endemic to vernal pool habitats,
including three shrimp species and the California tiger salamander.
This site itself provides the only known home for the federally
threatened delta green ground beetle.
Visit the Jepson Prairie
Preserve
Self-guided Tour: Open every
day during daylight hours.
Please stay on the trails, no smoking
or dogs permitted.
The best times to visit are in the spring while the wild flowers
are in bloom, although this Earth Cache is available all
year.
Waterproof footwear is advised during the
rainy season.
Docent Led Tours: Every Saturday
and Sunday at 10 a.m. beginning mid March through Mother's Day.
Walks last from one to two hours. A small donation is requested.
Call (707) 432-0150 ext. 200 for additional information. Bring
water, binoculars and your camera. Waterproof footwear is
advised.
¤ • ¤ Be aware of ticks and
critters when hiking in tall grasses!! ¤ •
¤
Logging
Requirements
Send me an email with Jepson Prairie on the first
line.
Answer the following:
1. Name 2 native plants found here.
2. Name 2 native aquatic animals found in the vernal pools
here.
3. From the road or nature trail, observe a mima mound and estimate
its height. For size, how does the one you are observing compare to
other nearby mounds?
4. Are the trees in the picnic area native to California?
5. Either:
a. Post a photo of yourself (group) with Olcott Lake in the
background.
b. Who placed the National Natural Landmark plaque at marker 15
along the Self Guided Nature Trail?
Jepson Prairie Preserve is owned and managed by the
Solono Land Trust in cooperation with the University
of California Natural Reserve System, the Nature Conservancy and
the California Department of Fish and Game
Congratulations to Kocao13 from
Dixon for being the first to visit!!