Inland Empire Resource Conservation District
25864-K Business Center Drive
Redlands, CA 92374
Phone: (909) 799-7407
CARCD District Merit Award Winner

Invasive Species Removal Projects

Click on the categories below to view more information on
Inland Empire Resource Conservation District's Invasive Species Removal Projects.

Invasive Species Profile
Giant Cane (Arundo donax)

Giant cane is a species of perennial grass found present throughout the Santa Ana watershed, located primarily within or adjacent to riparian systems, but also present in upland habitats.  The origins of the Arundo donax plant in southern California has not been precisely pinpointed; however, it is widely thought to have been introduced in the early 19th century into the areas surrounding the Los Angeles River, and has since spread throughout southern California and north in various levels of habitat infestation depending on climactic conditions.  Arundo donax grows at an extremely rapid rate of up to 4 centimeters per day, in clumped patches of long woody stems that experience semi-dormancy in winter months and/or periods of drought.  In North America it spreads primarily through plant fragments that break off and reestablish downstream.

 This plant causes a myriad of problems for native habitats and dependent environs including compromised water quality and quantity, elimination of existing and prevention of establishment of new populations of native plants and increased risk of fire and flood.   This reduction in native plant population presence reduces opportunities for foraging and shelter for wildlife and can raise temperature of water in areas that would otherwise be shaded by the overhang of native tall shrubs and trees.  The reduced habitat functionality of riparian systems due to the spread of Arundo donax continues to be a threat to survival of already marginalized species including the least Bell’s vireo (Vireo bellii pusillus) and the southwestern willow flycatcher (Empidonax traillii extimus).

The IERCD works to combat the presence of Arundo donax in its section of the Santa Ana River watershed through a variety of vegetation management projects performed over various regions of its service area.  Detailed summaries of IERCD-led large-scale removals with follow-up maintenance/monitoring of this highly invasive plant can be found in the “Projects” section of this website.


Castor bean (Ricinus communis)

The appearance of this plant varies according to age, presenting itself first as a perennial shrub and eventually becoming a woody tall shrub capable of growing to 15 feet tall.  Castorbean was introduced from warmer regions of Asia as both an ornamental and as a former agricultural crop, and escaped into wildlands via seeds spreading through humans and animals.  It is found most often adjacent to active/former agricultural fields and near roads and railroad tracks, and in warmer and wetter climates with less frequent periods of drought or excessive cold.  Its beans are toxic to many species including humans, horses, cattle, cats, and dogs.  In addition to its toxicity, castorbean is also quick to germinate and produce plants following fire, often displacing the functional native habitats previously in existence.  This reduction in native habitat, as with other species of invasives, reduces overall foraging and shelter opportunities for area wildlife and also negative impacts soil stability and health.

Tree of heaven (Ailanthus altissima)

This species was brought into southern California from China, both as an ornamental and through railroad workers, and is a tree capable of reaching heights of 65 feet.  As with other exotic plants used as ornamentals, it has escaped cultivation and become prolific throughout the state, primarily due to its spread through seed and through root sprouting. Tree of heaven is particularly prolific due to intensive seed production and tolerance of compromised air quality, allowing it to grow in locations inhospitable to native plants.   It is most dangerous to native riparian habitat health, where it displaces shrubs and trees providing shelter and food support for species of area wildlife. 

The IERCD has included tree of heaven as a species targeted for removal in invasive management projects since 2004.  Additional information on tree of heaven eradication efforts in the IERCD service area can be found in the “Projects” section. 


Tree tobacco (Nicotiana glauca)
Tree tobacco is a tall shrub/short tree capable of reaching 20 feet in height, and found throughout southern California. First introduced as an ornamental over 100 years ago, tree tobacco has spread prolifically due to establishment via both seed and runners. Once begun, tree tobacco plants grow rapidly and are capable of seed production within two years. They are most often found adjacent to disturbed areas and alongside roads, and can thrive in a variety of climactic conditions. As with other invasive species, tree tobacco crowds out other species of native plants, thereby reducing total available foraging and food sources for area wildlife. They are a particular threat to the coastal cactus wren (Campylorhynchus brunneicapillus) due to out competing populations of the prickly pear cactus (Opuntia littoralis), one of their primary nesting species.
Tamarisk or saltcedar (Tamarisk spp.)

In California, there are four different species of non-native Tamarisk plants, all of which are classified as tall shrubs/short trees, capping out at 26 feet tall.  They are all in California as a result of transport here for a variety of uses including as ornamentals, for windbreaks, and for erosion control.  They have escaped cultivation through seed dispersal as well as migration of plant fragments and now inhabit disturbed sites, burned areas, and riparian habitat. Their leaves contain salt glands, resulting in increasingly saline soils surrounding them, preventing establishment of functional, valuable riparian species.  Tamarisk shrubs and trees cause multiple problems in wildland areas, including increased flood risk due to infliction of changes on linear riparian systems in addition to crowding out of native species and permanent changes to soil composition.  


Multiple eradication efforts are underway in southern California, and the IERCD has historically and currently participated in Tamarisk control projects in its service area.  More information is provided in the “projects” section of the website.


Perennial pepperweed (Lepidium latifolium)

There are several species of problematic low-growing invasive plants within the IERCD’s service area, including the seemingly inexhaustible perennial pepperweed.  This shrub is thought to have been introduced into California in the 1930s via agricultural seed contamination and theorized to have spread as a result of hay bales distributed for use in erosion control. It can tolerate a variety of soil moisture and composition conditions, and develops a considerable root system contributing to its survival and spread.  The most threatening aspect of perennial pepperweed is its advancement as a monoculture throughout the state, occupying disturbed areas previously populated with functional native plants.

 The IERCD works to eradicate perennial pepperweed populations throughout its service area, most recently in partnership with the Riverside Land Conservancy over the Cienega Property located in the San Timoteo Canyon region of unincorporated Riverside County. More information on perennial pepperweed removal is located in the “Projects” section of the website.

Yellow starthistle (Centaurea solstitialis)

As with the aforementioned perennial pepperweed, yellow starthistle is thought to have entered California first through seed contamination, then spread through movement of humans, animals, and transport of hay and seed.  It is an annual invasive weed easily identified by its spiny yellow flowerheads, and has increased its statewide presence from 1 million acres in 1950 to over 15 million acres today.  It occupies a variety of habitats, especially those adjacent to disturbed areas found alongside transportation corridors and agricultural areas.   The most damaging effects of this species seem to be depletion of soil moisture in addition to transition of wildland areas from native coastal sage scrub habitats to monocultures of yellow starthistle.  The conversion of valuable native habitat reduces overall availability of food and foraging opportunities for dependent wildlife.

Arundo, Tamarisk & Castor bean Removal
Cherry Valley Garden Air Wash Removal
The Cherry Valley removal project was conceptualized in response to the presence of invasives in the Garden Air Wash, one of two major wildlife corridors in the community. The area targeted for this project provides local wildlife with an opportunity for passage through the northern part of the region, while the Cherry Valley corridor allows for such movement in the southern part of the community. Both are surrounded by rapidly developing regions, and are therefore critical for species’ survival. For this reason, the District works to ensure that these regions are hospitable to species of native wildlife and vegetation, meaning that any invasive non-native vegetation identified in proximity must be eradicated as quickly as possible. The wash also leads to the San Timoteo Creek, a tributary of the Santa Ana River, which is further justification for treatment of invasives in the area.

This project began in 2002, and involved the removal of approximately three full acres of invasive species including giant cane (Arundo donax), castor bean (Ricinus communis), and tamarisk (Tamarix spp.) from a 22.5-acre eradication site. Mechanized methods of removal were employed for this effort, with follow-up spraying and monitoring occurring quarterly until removal was complete. Currently, the project site is 99% eradicated and is monitored on a bi-annual basis by District staff to ensure continual control of invasives.  
Cajon Wash Arundo Removal
The conceptualization of both the Cajon Pass I and Cajon Pass II Removal projects took place in 1999. Each project involved partnering with the Santa Ana Watershed Association (SAWA) and the United States Forest Service (USFS), and they both targeted the highly invasive giant cane (Arundo donax). Both removal efforts were placed in the Cajon Pass region of the Inland Empire RCD’s boundaries, a site whose geology, vegetation, and hydrologic features have all been heavily influenced by the existence of the San Andreas Fault. 
The Cajon I project involved the removal of 19 acres of giant cane (Arundo donax); three of those acres were located in Lost Lake, a sag pond in the Pass created during movement of the San Andreas Fault, while the remaining 16 were located within the rest of Cajon Creek. The agreements were executed in 1999, with the initial removal taking place in 2000 and the maintenance/monitoring being completed in 2003. Currently, this site is monitored on a bi-annual basis by the IERCD field ecologist. In 2009, the IERCD funded the development of a restoration plan for a region of the lake formerly populated by giant cane (Arundo donax) along with oversight from SAWA staff, with the project set to be conducted in 2010.
Cajon II involved the removal of invasive vegetation along eight miles of the 215 freeway, north of its intersection with the 15 freeway, within Cajon Canyon. The initial removal for Cajon II began July 15th, 2000, with the maintenance/monitoring phase ending June 15th, 2002. Currently, this site is monitored at least annually for re-growth but it has been tremendously successful, with less than 1% re-growth.
East Twin Creek Arundo Removal

The East Twin Creek removal project was initiated in 2002 by the East Valley Resource Conservation District, prior to its consolidation with the Inland Empire West Resource Conservation District which resulted in what is now the Inland Empire Resource Conservation District.  The project site is located in the foothills of the San Bernardino Mountains, beginning where East Twin Creek is coincident with Coldwater and Strawberry Canyons, downstream for a total site length of approximately five miles. The total project site size is 100 acres, of which approximately 25 were infested with giant cane (Arundo donax), castor bean (Ricinus communis), and saltcedar (Tamarisk spp.). This was especially problematic as the majority of the acreage was located directly adjacent to East Twin Creek, a tributary of the Santa Ana River. The extraordinary ability of giant cane to colonize locations via hydrologic conduction of plant material made this project a priority, in order to eradicate local populations as well as to prevent further growth downstream.

Since the initial treatment, this site has been maintained annually to prevent re-infestation of giant cane, as well as to encourage the re-colonization of the site by native species of vegetation. These efforts have been very successful, as the presence of giant cane is less than 1% of the acreage at East Twin Creek, and the appearance of native species of willow (Salix spp.), cottonwood trees (Populous fremontii), and mulefat shrubs (Baccharis salicifolia) has been consistent in each year post-initial treatment. This careful bi-annual monitoring work which has resulted in restoration of the East Twin Creek site by valuable, native wildlife-sustaining species of vegetation will continue in perpetuity.

Etiwanda Preserve Removal
The North Etiwanda Preserve encompasses a parcel of open space in excess of 1,200 acres, north of the City of Rancho Cucamonga in the County of San Bernardino. The Preserve is mitigation for construction of the 210 freeway, and will be conserved in perpetuity in observance of impacts from that project. The property is located between Day Canyon Wash and East Etiwanda Wash, and is home to multiple native habitats and dependent species, including riparian woodland and the endangered Riversidean alluvial fan sage scrub. The parcel is one of the largest preserved habitats in the region, and therefore must be kept suitable for sustaining local populations of native vegetation and wildlife. In keeping with this goal, populations of non-native species located on the property are targeted and removed by area conservation organizations, including a 2004 giant cane (Arundo donax) eradication by the IERCD.

The giant cane removal effort involved approximately ½ acre of vegetation located within the challenging terrain of the Preserve. The initial eradication was completed In November of 2004, with a five-year spray contract commencing in the spring of 2005. Currently, the site is 99% eradicated, and annual visits by District staff will continue in perpetuity to ensure minimal re-growth of invasive species.

Harrison Canyon Arundo Removal
The Harrison Canyon project site is located within a two-mile stretch of the lower portion of Harrison Canyon, in the City and County of San Bernardino. The project was conceptualized in conjunction with the Santa Ana Watershed Association staff; along with other local invasive species removal projects, this undertaking targeted non-native vegetation located in or adjacent to tributaries or sub-tributaries of the Santa Ana River. The specific plants targeted included giant cane (Arundo donax), castor bean (Ricinum communis) and tamarisk (Tamarix spp.).

When the project began, the IERCD then known as the East Valley RCD, contracted for the removal of 30 acres of stands of 75-100% pure giant cane as well as smaller stands of castor bean scattered throughout the site. The original agreement was executed in January of 2004, and involved the initial physical removal of the invasive biomass, followed by five years of maintenance and monitoring to ensure minimal re-growth of target species.  The agreement terminated in January of 2009, and the final walk-through of the site took place on May 29th, 2009; at this final meeting, the IERCD certified that the contracted removal agency had been successful in eradicating all but <1% of the targeted invasives. The site will continue to be monitored periodically by the IERCD, and will be turned over to staff of the Santa Ana Watershed Association in January of 2011.
Highway 210 Arundo Removal
This project site is located adjacent to the 30/210 highway, where it intersects the cities of Redlands and Highland in the County of San Bernardino. The area was selected for application of herbicide treatment, after District staff discovered thirty acres of non-native species including giant cane (Arundo donax), castor bean (Ricinus communis) and tamarisk (Tamarix spp.). The East Valley RCD began working on this project in an effort to eradicate all major patches of giant cane from the District’s service area. 

The initial removal was completed in July of 2001, with five years of herbicide treatment and follow-up monitoring required, resulting in project completion in August of 2006. Currently, the IERCD field ecologist monitors this site, which has experienced very little re-growth of giant cane, but has experienced re-invasion by the opportunistic tree tobacco (Nicotiana glauca). Removal of tree tobacco is slated for late fall of 2010; afterwards, annual monitoring of the site should be sufficient to ensure continued control of invasive species.

The main justification for treatment of invasives at the site was its ultimate connectivity to a drainage moving first through citrus groves in the City of Redlands, and ultimately emptying directly into the Santa Ana River. This project was made possible through funding provided by Federal dollars received by the East Valley RCD, now the IERCD, which were earmarked for projects involving the documentation and removal of invasive species in the Santa Ana Watershed.

Mill Creek/Day Creek Removal
In 2005, the Inland Empire Resource Conservation District became the product of the consolidation of two prior independent districts, the Inland Empire West RCD and the East Valley RCD. Accordingly, the earlier removal projects beginning prior to this year were initiated either by the IEWRCD, or by the EVRCD. This project was created and implemented by the staff of the Inland Empire West RCD, under a larger effort to eradicate invasive species, particularly giant cane (Arundo donax) from the Santa Ana River and associated tributaries.
The project areas targeted for this removal included Day Creek, a channelized waterway/retention basin located east of the 15 freeway, between Jurupa and Philadelphia Streets. A second site was also selected, which was Mill Creek, an area of approximately 125-acres in size. Mill Creek begins on private property just north of Hellman Avenue to the San Bernardino County line to the south, where it enters the Prado Flood Control Basin. The agreements for these two project sites were executed in 2004, and both targeted giant cane (Arundo donax) in addition to castor bean (Ricinus communis) and tamarisk (Tamarix spp.).
The removal portion of the project was completed by Natures Image in Spring/Summer 2003, and involved extraction of invasive biomass using mechanized methods to pull and subsequently shred the material. Following the initial removal, a five year herbicide spray contract was awarded to an outside contractor in January 2004 to treat any reappearing growth inside the project area using a foliar spray technique to apply a wetlands-approved herbicide.  In January 2009, the site was declared a success and the spray crew employed by the Santa Ana Watershed Association (SAWA) began annual monitoring to ensure continued control of invasive species.
The challenge with this site is that even after removal of target species, many other opportunistic non-native such as perennial pepperweed (Lepidium latifolium), black mustard (Brassica nigra) and castor bean (Ricinus communis), continually re-colonized project areas.   For this reason, continued monitoring is necessary to not only ensure that the originally targeted vegetation does grow back, but also to prevent these other noxious non-native weeds from getting established.    
Mentone-Morrey Arroyo Arundo Removal
This project involves two sites; the first is at the Third Avenue Drainage located on the border separating the City of Redlands and the unincorporated County of San Bernardino property knows as Mentone. The second site is located in the Morey Arroyo drainage, adjacent to Alabama Street in the City of Redlands and County of San Bernardino. Both of these project areas are smaller than what the District would typically take on; however, both sit adjacent to the riverine system that eventually leads into the Santa Ana River, which is the main conduit in the watershed. 

The staff of the Inland Empire Resource Conservation District documented the presence of invasive species including giant cane at both of these sites, both of which are tributaries or sub-tributaries of the Santa Ana River, in the summer of 2009. The contract for removal was executed in the fall of 2009, and targeted giant cane (Arundo donax), resulting in all stalks being removed before the end of the year. Now that the existing biomass has been removed, the maintenance and monitoring portion of the project will begin, with termination of agreements scheduled for fall of 2010. Once the site is declared successful, IERCD staff will take over the responsibility of actively monitoring for re-growth, and eradicating such vegetation should it appear.
Norco Arundo Removal
The Norco Burn effort is another project conceptualized and implemented by the District in its mission to eradicate giant cane (Arundo donax) from the upper Santa Ana Watershed. This project site begins on the north and south sides of the Santa Ana River, just west of the Southern California Edison power lines adjacent to the Goose Creek Golf Course in the City of Mira Loma, and continues downstream to Hamner Avenue in the City of Riverside. The original size of the Norco Burn project was 300 acres of habitat in Riverside County, which was targeted for removal due to concerns from staff from the United States Fish and Wildlife Service after massive fire events burned large portions of the project site. 

The initial removal began in March of 2003, with an additional 185-acres added onto the original project area in order to maximize the invasive species removed. The project area underwent mechanical removal of invasive species biomass, followed by five years of herbicide treatment to prevent re-growth. The spray contract was set to expire in March of 2009, but was renewed by the Inland Empire RCD, to include all original project acreage. In addition to giant cane (Arundo donax), the 2009 Norco Bluffs/Burn contract targets additional invasive vegetation including tamarisk (Tamarix spp.), perennial pepperweed (Lepidium latifolium), tree of heaven (Ailanthus altissima), tree tobacco (Nicotiana glauca) and castor bean (Ricinus communis). Spraying of wetlands-approved salt-based herbicides commenced in the fall of 2009 and will terminate in fall 2010, with five years of monitoring and maintenance planned for the site. 
San Bernardino County Wide Arundo Removal
The majority of removal efforts conducted by the IERCD involve single site projects that target non-native species in large-scale areas. In contrast, the San Bernardino County-Wide Removal focused on multiple sites, typically much smaller than other projects conceptualized and implemented by the District. All infestations identified for eradication in this project were located in San Bernardino County, for the dual purpose of ensuring no untreated gaps between larger project sites as well as increasing total acres treated in the headwaters and upper portion of the Santa Ana River. Treatment in these areas increases the success of projects downstream, as the amount of biomass with potential to migrate via water conduction is reduced.
The total project area encompassed 17 total acres, of which approximately four were fully infested with non-native species including giant cane (Arundo donax), castor bean (Ricinus communis) and tamarisk (Tamarix spp.). 
The removal began in January of 2006, and involved a variety of methods of eradication due to differences in slope, erosion, and degree of infestation at the different project sites. Once the biomass was removed, the individual sites were treated for re-growth using foliar application of a wetlands-approved herbicide to minimize impacts to species of native vegetation and wildlife. This contract will continue until 2011, at which point the IERCD staff will take over annual monitoring responsibilities in order to ensure continued control of the site.
San Bernardino Golf Course Arundo Removal
The San Bernardino Golf Club is located in the City and County of San Bernardino, on the north side of the Santa Ana River. Funds for removal of non-native vegetation were applied at this site, in response to the documentation of the presence of three separate highly invasive species on the grounds of the course. This discovery was especially troubling due to the proximity of the course to the Santa Ana River mainstem.

This project was conceptualized in cooperation with SAWA, the non-profit agency with which the IERCD often collaborates on such efforts. The actual project area represented less than one acre in size, and consisted of giant cane (Arundo donax), tamarisk (Tamarix spp.), and castor bean (Ricinus communis). Removal of these species was complicated by the presence of native vegetation intermixed with the invasives; for this reason, the contractor selected for the job employed methods of hand-removal of all target plants. The contract began on October 23rd, 2002 and expired on the same day in 2007. Following initial removal, five years of maintenance and monitoring were completed within the project area.

Currently, the IERCD field ecologist is monitoring the site and treating any re-growth detected in and around the project area. The need to continue to maintain this site as a location devoid of invasive species is due to its location adjacent to the main linear drainage of this watershed, the Santa Ana River. Re-growth is currently less than 1% and it is projected that annual monitoring and spot treatment will maintain this number in perpetuity.

Santa Ana River at Mission Arundo Removal
The Mission for Arundo project area is a 300-acre site, located adjacent to the Tesquite Landfill and Santa Ana River, in the City and County of Riverside. Of the entire site, over 1/3 of the acreage was infested with invasives, the majority of which consisted of giant cane (Arundo donax) along with additional species present in smaller acreages. Staff working on this project recognized the potential difficulty in removing non-native species in the consistently inundated project site; however, this constant movement of water through the region made removal even more important as the invasives targeted easily spread via hydrologic conduction.

The initial removal work began in February of 2006, using heavy mechanized equipment with feacon grinder attachments for mulching the cut biomass. The work temporarily ceased in April of 2006 when the endangered least Bell’s vireo (Vireo bellii pusillus) was located within the project boundaries. Biologists employed by the Santa Ana Watershed Association spent a significant amount of annual staff time monitoring regional removal projects, in order to ensure absence of endangered and/or threatened species. Removal resumed in September of 2007, which is the month that marks the official end of the nesting seasons for vireo, and continued until completion in December 2007. The individual population stability of wildlife such as the least Bell’s vireo is one of the goals set in removal of invasive vegetation in the region; therefore any activities considered harmful, even those done in conjunction with an overall beneficial project, are immediately stopped and do not resume until absence of said species can once again be determined. 

Since the end of the initial removal in 2007, an outside contractor has monitored the area and completed herbicide treatments to any visible re-growth on a monthly basis. Currently, the site is approximately 70% controlled, and the District anticipates this will reach 95% by the end of the fifth year of spray treatment. The herbicide treatment will continue until 2012, at which point the presence of invasives on the project site is targeted to be less than 5%. At that point, IERCD staff will take over monitoring and occasional treatment of re-growth on a quarterly basis. The prevention of re-growth of aggressive invasive species is critical for a project area of such considerable size, as its absence allows for restoration of large parcel of public land that will be preserved in perpetuity.
Santa Ana River at Mission Expansion Arundo Removal
In the fall of 2008, the Inland Empire Resource Conservation District began working on plans for extending the existing Mission for Arundo project to include additional adjacent acreage. The District was informed that the land to the south of the Mission for Arundo project, which previously was slated for a mitigation bank for the City of Riverside, would now no longer be used in that capacity. In response, the IERCD created the necessary documentation to eradicate invasive species in this 25-acre parcel, in order to increase total non-native vegetation adjacent to this portion of the Santa Ana River.
Out of the 25-acre site, approximately 19 were partially to fully infested with giant reed (Arundo donax), castor bean (Ricinus communis), and saltcedar (Tamarisk spp.). In December of 2008, the IERCD conducted a pre-project walk with interested contracting agencies for the purposes of estimating bids for the work. The contract was subsequently awarded to the lowest bidder, and the removal of biomass began on January 27th, 2009. The extraction of vegetation was finished in six weeks, and was followed by a foliar application of wetlands-approved herbicide to the entirety of the project area in order to discourage re-growth. Currently, approximately 70% of the site is under control, and it is estimated that the entire site will be at least 95% eradicated by the end of the project in October of 2010. At the end of the contract, District staff will assume the responsibility of annual monitoring to continue control of the site.
Santa Ana River Mainstem Removal Project
The Santa Ana River (SAR) Mainstem project includes 28 miles of the Santa Ana River, beginning at the top of Mill Creek and including tributaries of the mainstem such as Mill Creek, Mission Channel, City Creek, and the Zanja Irrigation Channel in the City of Redlands. The project was conceptualized due to its infestation with multiple species of invasive vegetation, as well as its position in the upper Santa Ana River Watershed. The collective goal of all removal agencies within the region is to target and perform removal of existing invasive species within the next fifteen years; in order to accomplish this, all species must be removed in a methodical fashion, beginning from the top of the watershed and moving down. The 28 miles of the SAR mainstem and associated local tributaries represented a project area with various percent infestations of invasive species, including giant cane (Arundo donax).

The initial removal of invasive biomass was completed in June of 2003, despite being repeatedly delayed due to the presence of two sensitive regional species, the Santa Ana River woolly star (Eriastrum densifolium sanctorum) and the San Bernardino kangaroo rat (Dipodomys merriami parvus). The existence of these species at the project site required full-time biological monitoring, which complicated the timeline of the removal; however, ultimately 86-acres of invasives were removed.  Following the cutting and mulching of biomass, the area was treated with an Environmental Protection Agency-approved herbicide using a foliar spray application technique. This is standard in all removal projects, and is done in order to discourage re-growth of the target species.  
The project contracts expired in June of 2008 and the site is now monitored on an annual basis by the Inland Empire Resource Conservation District. The Santa Ana River is the main conduit of the watershed, and thus must continue to be a priority for projects conducted by conservation organizations in the region. The IERCD will continue to explore options for continued active removal at the River as funding allows.
San Timoteo Creek Removal
San Timoteo Creek is a tributary to the Santa Ana River and at 14 miles in length is significant enough in size to warrant designation as a sub-watershed of the Santa Ana Watershed. It also houses large swaths of valuable riparian habitat and is home to multiple varieties of native wildlife and plants. In 1997, San Timoteo Creek was targeted by the District as an appropriate removal site in light of expanding populations of invasive species, including giant cane (Arundo donax). The District recognized the difficulty in tackling such a large project area, and thus developed an initial removal and subsequent maintenance and monitoring plan to take place in four main phases. This initial removal was completed in 2001. Since initial removal was completed in 2001 the District has adopted a very active monitoring program of this 239-acre removal site. When isolated patches are encountered, they are cut hauled to the high water mark and the stumps are treated with an Environmental Protection Agency aquatic approved herbicide. The canyon is currently >98% eradicated and is continually monitored on a bi-annual basis.
Tree of Heaven
Applewhite Campground and Picnic Area Removal andTreatment Project
The Applewhite campground is located within the Lytle Creek region of the San Bernardino National Forest, in the northern section of the IERCD’s service area. Lytle Creek is a sub-watershed of the Santa Ana Watershed, and is characterized by multiple populations of both coniferous and deciduous trees, including mesquite (Prosopis glandulosa torreyana) and Coulter pine (Pinus coulteri). In addition to native trees, the Applewhite campground is also home to a number of infestations of non-native vegetation, of which the most prolific appear to be tree of heaven (Ailanthus altissima) and tamarisk (Tamarix spp.). The presence of these invasive species compromises the biological integrity of the site, which is already increasingly fragile due to the proximity of human residents recreating adjacent to the natural habitat.

In November of 2009, the IERCD worked with the United States Forest Service (USFS) to conduct the removal of approximately one full acre of tree of heaven, interspersed among three acres of habitat. The District and crews working on behalf of the USFS employed the “cut and daub” technique for removal of this invasive tree, a method involving the felling of trees, followed immediately by hand application of a wetlands-approved herbicide. This method is widely used on land classified as USFS-patrolled property, as it is the removal method least likely to contaminate adjacent stands of natives during treatment of invasive species. Following the initial treatment, the District conducted one follow-up visit to gauge site success, and will continue to actively monitor beginning in September of 2010, at the end of the official nesting season.

The IERCD also participated with the Forest Service in a removal project located in the Applewhite Picnic Area, also in the Lytle Creek watershed. In this location, tree of heaven was also targeted; however, its small size rendered it inappropriate for treatment using the cut-and-daub method employed at the adjacent campground project. Instead, IERCD staff along with USFS staff used foliar spray application of wetlands-approved herbicide. Currently, this site is only 85% under control, and therefore will continue to be monitored and treated by IERCD staff to ensure total control of invasive plants at the site.

Yellow Starthistle
Yucaipa Yellow Starthistle Removal Project
In 2009, the board and staff of the Inland Empire Resource Conservation District began conducting removal of multiple populations of yellow starthistle (Centaurea solstitialis) located throughout the eastern edge of the District. This species of noxious weed has historically been a much larger issue in the northern portion of the state, where its presence is so ubiquitous that tackling it during removal projects is often not even attempted. However, it has recently been appearing in isolated patches throughout the service area of the IERCD and has therefore been placed onto the District’s removal list. This population is one of several recently located and treated by the IERCD, with others in cities including Cherry Valley, Calimesa, and in other parts of Yucaipa. A spreading population was also recently located adjacent to San Timoteo Creek, a tributary of the Santa Ana River.
The majority of removal planning including research, budgeting, and the development of all removal methodologies was completed in late 2009. The development of entry agreements and landowner permission letters, as well as final project scheduling was completed in early 2010. Initial landowner resistance to this project was significant enough to warrant calls between IERCD staff and affected residents; however, ultimately, area homeowners gave permission for the project and it proceeded as planned.

In March of 2010, the physical removal began, after determining absence of breeding birds including the least Bell’s vireo. A salt-based herbicide approved by the Environmental Protection Agency was applied to all affected areas, by IERCD staff in conjunction with removal technicians from the Santa Ana Watershed Association (SAWA). SAWA equipment including a Polaris vehicle was used in these treatment applications, allowing employees to reach larger areas than previously allowed during the traditional method of application on foot. Following this initial removal, there will be additional treatment, follow-up maintenance and monitoring for a minimum of two years at the site.

Upon project completion, annual monitoring will continue in perpetuity to ensure minimal re-growth. The elimination of local populations of this species will assist with the desired regional extirpation required to prevent the widespread presence of this plant as it exists in northern California. 
French Broom
Yucaipa French broom Removal
One of the main functions of the IERCD is to identify populations of invasive species within District boundaries, followed by conceptualizing and implementing a plan for maximum possible eradication. There are several core species District staff have been treating for years, including gant cane (Arundo donax), tree of heaven (Ailanthus altissima) and castor bean (Ricinus communis); however, recently, the District has added several additional species to this established list including perennial pepperweed (Lepidium latifolium) and yellow starthistle (Centaurea solstitialis). 

Another recent addition is French broom (Genista monspessulana), a rapidly spreading non-native shrub found in multiple locations within California, one of two locations worldwide where it is especially problematic. The ability of French broom to produce copious amounts of seed, to colonize disturbed areas, and to re-sprout after traumatic conditions such as freezing and cutting has allowed it to thrive and spread. This hardiness is also what is most dangerous about broom, as it readily out-competes natives and is difficult to eradicate. The importance of early control of species such as French broom cannot be overstated; if allowed to spread, it becomes extremely costly to treat, and causes considerable damage to the native habitats it invades.

In 2008, the District was notified by a local professor of a population situated in a regional park in the City of Yucaipa and County of San Bernardino. After an initial inspection by the Field Ecologist, the population was then mapped and scheduled treatments with an Environmental Protection Agency-approved herbicide began in August 2008. A total of 5 treatments were conducted and the population has since been eradicated. Routine annual monitoring will continue in perpetuity, in order to ensure continued control of French broom at this site.
African Clawed Frog
African Clawed Frog Removal
In 2009, the IERCD was contacted by the California Department of Fish and Game (CDFG) to partner on an effort to eradicate the invasive South African clawed frog (Xenopus laevis) from locations within or adjacent to riverine systems in the Santa Ana Watershed. One location of particular concern was the San Bernardino Golf Club, located off of Waterman Avenue in the city of San Bernardino. At this site, there are several locations in which the hardy South African clawed frog may survive, and there had been multiple sightings of such animals by employees of the course. The CDFG recognized the need for eradication from a location in close proximity to the Santa Ana River, and asked the District for assistance in the removal effort.

This species was targeted for removal due to its degree of invasion in the watershed, as well as its predation upon native frogs including the California red-legged frog (Rana draytonii). The South African clawed frog is well-adapted to the local Mediterranean climate, which has enabled it to establish a dense population that is spreading. The mild conditions of southern California enable year-round breeding, which can result in 27,000 eggs per breeding session, per frog, and its tolerance for elevated toxins in water have allowed the population to continue to rise.
For this project, the District partnered with CDFG, the San Bernardino Golf Club, and the Riverside-Corona Resource Conservation District (RCRCD) in a four-month eradication effort. The CDFG coordinated the project and participants, and the RCRCD performed initial trapping to minimize the population, prior to treatment with pesticides. The IERCD then applied standard pool chlorine to the ponds to eliminate existing frogs, and built a temporary fence to minimize the potential for escape to non-treated waters. Monitoring by IERCD personnel occurred weekly to check on the fencing and look for the presence of frogs. The fence was taken down in late December and post-trapping was conducted. Ultimately, the population was reduced but not eradicated and the IERCD is working with the CDFG to build a methodology to accomplish this task.