Invasive Species Eradication
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Arundo
donax, also known as giant reed or giant cane, is a
prolific invasive weed in the Santa Ana River watershed.
SAWA has been actively removing arundo from the Santa Ana
watershed. The photographs are before (left) and after (right)
pictures from an arundo removal project in San Timoteo Creek
that was performed in the winter of 1998. Native vegetation
has begun to return the site. SAWA has performed some tamarisk
removal within the Santa Ana Watershed, often in conjunction
with arundo removal. |
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Preservation of Endangered Species
Efforts at protection of the least Bell's
vireo and the Willow Flycatcher have concentrated on two
major causal factors. Cowbird trapping has been conducted
extensively in some portions of the Santa Ana watershed,
with most of the focus of SAWA's efforts on the Prado
Basin and the Hidden Valley Wildlife Refuge. A large-scale
population study has also been conducted in this area
in conjunction with the Orange County Water District and
the U.S. Fish and Wildlife Service. In addition, vireo
surveys have begun in San Timoteo Creek and cowbirds are
being trapped there. SAWA's efforts of arundo and saltcedar
eradication within the basin are also anticipated to benefit
vireos (regrowth of native vegetation will provide vireo
habitat). While the vireo continues to be an endangered
species, there is some indication that they are recovering
in the Santa Ana Watershed. The number of nesting pairs
of vireos has steadily increased since 1986.
Native Fish Stream
The
Riverside-Corona Resource Conservation District (RCRCD)
has constructed a native fish stream to help augment native
fish populations in the Santa Ana River Watershed and
its associated tributaries. The three fish that are currently
in the stream are the Santa
Ana sucker (Catostomus santaanae), arroyo chub (Gila
orcutti) and the speckled dace (Rhynichthys osculus ssp).
All of these fish were once common on the river and its
tributaries, but over time, sedimentation, runoff, water
diversions and flood control have all combined to change
the hydraulics of the river. The
Santa Ana sucker was once in abundance in the drainage,
and is in small numbers in the upper San Gabriel River
and the Santa Clara River, but because of the marked decline
in numbers of these fish, the U.S. Fish and Wildlife Service
listed the sucker as threatened under the Endangered Species
Act.
Native Plant Nursery
The Native Plant Nursery is located at
the Riverside-Corona Resource Conservation District (RCRCD),
one of SAWA's member organizations. It is a small-scale
propagation and revegetation facility used primarily for
the growing of plants native to Southern California.
A number of trees and shrubs are grown
for use in revegetation projects within RCRCD boundaries,
and in conjunction with SAWA projects There are
30 growing tanks used for propagation of willow and mulefat
cuttings and a 2,000-sq-ft container stock area used in
revegetation projects for both riparian and upland restoration
projects. Nursery stock is either grown from seed
or from cuttings, and is placed in containers after the
first year. Cuttings are taken in the winter dormancy
period and grown in the spring and harvested again in
the winter for planting the same year. The growth
from some of the cuttings is used as the following year's
crop, while other cuttings are taken from plant in the
field. Production currently stands at 600 to 800
cuttings per year, and more than 200 2-gallon containers
of various species. Some of the more common trees and
shrubs grown are white elder, red-bud, mulefat, red willow,
and sycamore. If a project requires revegetation,
a number of trees could be propagated at the nursery for
use on the project. Growing cuttings for use in
the field usually takes from eight months to a year.
Revegetation with nursery stock is recommended only as
a second course of action. If year-round water is
available, nature can revegetate an area after fire, flood,
or invasive plant removal as fast, or faster, than planted
stock. Use of nursery stock is recommended only
if required by an agency plan, or if it would increase
native plant establishment from a removal area.
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P.O.
Box 219
Chino, CA 91708
909-606-1933
Lee Reeder,
Executive Director, ext. 105
Jennette Corbitt,
Executive Assistant, ext. 101
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