Invasive Species Eradication

Preservation of Endangered Species

least Bell's vireo/Willow Flycatcher

Efforts at protection of the least Bell's vireo and the Willow Flycatcher have concentrated on these 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, with cowbird trapping to begin shortly. 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, but because of the marked decline in numbers of these fish, the U.S. Fish and Wildlife Service recently 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 grownfor 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 years crop, while other cuttings are taken from plant in the field.  Production currently stands at 600to 800 cuttings per year, and over 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 8 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.