Inland Empire Resource Conservation District
Restoration Projects
Active Restoration
The process of restoring natural open spaces is one that can involve a variety of steps, depending upon the biological characteristics of individual project sites. In some instances, eradication involving initial cutting and mulching of biomass, followed by herbicide treatments and periodic monitoring, is sufficient in order to ensure continued control of invasives at the project site. Often, these removal projects are accompanied by the passive revegetation of the site by species of native California plants naturally adapted to the regional climactic regime. For example, in the District’s East Twin Creek removal project, the eradication of Arundo donax, followed by herbicide application and annual monitoring resulted in the re-colonization of the formerly infested site by species of riparian shrubs and trees. Volunteer plants that appeared at the project site included species considered to be highly valuable to local native wildlife and included mulefat (Baccharis salicifolia), willow (Salix spp.), cottonwood (Populous fremontii), and California sycamore (Platanus racemosa).
In other cases, passive revegetation and monitoring is insufficient in attempting to stifle the presence of non-native plants. In projects sites highly prone to reinvasion by other species of invasives, the District has begun to implement active revegetation of removal areas with native species of riparian shrubs and trees. Typically, these restoration efforts are done using pole cuttings taken from local native vegetation, then planted in the optimal season for this region of California, in the late fall and early winter. The cuttings are tended to by the District, and monitored for stress and disease, with assistance from the District’s partner agency, the Natural Resources Conservation Service (NRCS). Survival rates are monitored and dead plants are replaced by the IERCD to ensure maximum presence of valuable native species at active revegetation sites.
The following projects are examples of past and future efforts to exert biological control over former removal sites, in the form of active revegetation with native California species.
Alluvial Fan Sage Scrub Project
The Inland Empire is home to a number of endangered species of wildlife and vegetation, including multiple plant communities whose ranges are being reduced due to urbanization. One of these threatened communities is Riversidean alluvial fan sage scrub, a Mediterranean shrubland found in washes and alluvial fans, and characterized by white sage (Salvia apiana), buckwheat (Eriogonum fasciculatum), cholla (Opuntia spp.) and scalebroom (Lepidospartum squamatum), among others. In recognition of the threats to the viability of this plant community, the Riverside-Corona Resource Conservation District partnered with the IERCD, the Santa Ana Watershed Association (SAWA), the United States Forest Service (USFS) and the California Native Plant Society (CNPS) to implement a project aimed at observing, propagating, and distributing local populations of species included within this plant community. The overall goal of the project is to preserve the remaining local Riversidean alluvial fan sage scrub, in order to ensure its continued existence in the region.
For this project, the IERCD will participate in the surveying and recording of successful populations of local Riversidean alluvial fan sage scrub. Densities, locations, and relationships between species will be documented for the purposes of creating propagation plans that most closely mimic the natural processes of the target species of this sage scrub community. The IERCD field ecologist will receive training from the Riverside-Corona RCD as well as with the California Native Plant Society to perform these vegetation surveys in the field.
Additionally, the District will provide outreach following the initial work done by the other project partners with local agricultural operations in the City of Redlands. The extent of outreach by the District will depend on the success of the pilot project; if both of these elements are successful, the District will begin an outreach campaign to other small, local agricultural operations to secure levels of interest for program participation. Once interest has been established, the IERCD will work with the USFS, the RCRCD, and SAWA to provide in-kind staff time in a variety of potential capacities, including additional landowner outreach and creation of maps demonstrating outreach successes and failures.
The restoration of natural lands in the District’s service area is a high priority of IERCD staff; such work will help to restore the biological diversity and functionality of these habitats, which will in turn increase the amount of species they are able to support. The propagation of native species included within the alluvial fan sage scrub habitat will help the IERCD and other cooperating agencies in the collective mission of maximum restoration of wildland acreages.
Lost Lake Revegetation Project
Lost Lake is a sag pond, located in the Cajon Pass region of the Inland Empire Resource Conservation District’s service area. It is characterized by the presence of native riparian vegetation and native endangered and/or threatened birds, including the least Bell’s vireo (Vireo bellii pusillus) and the southwestern willow flycatcher (Empidonax traillii extimus), in addition to species of invasive vegetation. The District previously performed eradication of giant cane (Arundo donax) at the lake, and post-removal, discovered the re-colonization of the former removal site by the highly invasive black mustard (Brassica nigra). In response, District staff formulated a plan for active revegetation of the site, as passive recolonization at that particular location was proving to be insufficient in discouraging non-native growth.
The District worked with staff from the United States Forest Service (USFS) and the Santa Ana Watershed Association (SAWA) to generate a plant palette and installation and monitoring timeline for the Lost Lake project. Once the palette was finished, the District Field Ecologist worked with staff from SAWA to take cuttings of desired revegetation species, including but not limited to arroyo willow (Salix lasiolepis), red willow (Salix laevigata), common bulrush (Typha latifolia), and panicled bulrush (Scirpus microcarpus). The Field Ecologist took cuttings of some of the target species and is currently propagating them off-site, to be planted in September of 2010. After planting, the District will perform quarterly monitoring to ensure maximum survival of cuttings.
The revegetation of Lost Lake will benefit the former giant cane (Arundo donax) site and dependent species by providing healthy native specimens in place of the previously existing invasive vegetation. Native plants exist with rather than compete against other natives, and also provide benefit in terms of erosion control and support for species of native wildlife. The District will continue to monitor the site in perpetuity, and replace plantings as-needed to ensure site success.
Oak Glen Basins Project
In 2006, the IERCD began working in conjunction with the City of Yucaipa on the Oak Glen Basins Project. The main concept of the project was the creation of a system of detention basins to treat nuisance and storm flows; benefits of the project were predicted to include sediment control, flood control, water recharge, native habitat creation and restoration, as well as a forum for public recreation and education. This project was formulated and implemented to prevent the flooding and water supply issues projected to affect the City of Yucaipa; such issues are predicted to occur as a result of recent fires, projections of heavy winter and spring storm flows, and rapid population growth with an accompanying rise in paved surfaces. The basins help to alleviate these issues by encouraging groundwater infiltration, reducing sediment loads downstream, and educating the public on the importance of water conservation in the arid climate of the Inland Empire.
The IERCD assisted with the restoration and creation of native habitat, as well as with the public outreach portion of the project. The District providing funding for informational and educational signs to be placed at intervals on walking trails constructed for public use. The IERCD also participated in the removal of non-native vegetation as well as the replanting of the restored and created project areas with species of native vegetation. The habitat restoration resulted in the elimination of invasive species at the project site, as well as the encouragement of the presence of native vegetation which supports local species of wildlife. The educational signs highlight the benefits of the basins to the public, and also provide information on the importance of creating and protecting native habitats, as well as using water resources in a sustainable manner.
San Timoteo Creek Restoration Project
In 2003, the staff of the Inland Empire RCD began working on the Reach 3B Mitigation project, which resulted from impacts to San Timoteo Creek, a tributary of the Santa Ana River, due to work by the United States Army Corps of Engineers (USACE) on the Reach 3B flood control project. In recognition of impacts to the creek and dependent species, the USACE contracted with the Santa Ana Watershed Association (SAWA) to perform restoration and preservation work in order to offset the disruptive work of the project. In exchange for the funding from the USACE, SAWA was required to remove invasive vegetation, preserve functional open space, and perform sensitive species’ monitoring in the San Timoteo Creek region, with the help of its member RCDs including the Inland Empire RCD.
In 2009, the IERCD began working on the revegetation goal of this mitigation project, which was placed on an upland/riparian transitional zone adjacent to San Timoteo Creek. The approximately one-acre project site was infested with tree of heaven (Ailanthus altissima) which was removed by the District using mechanized equipment, followed by on-site mulching of removed biomass. After the initial elimination of tree of heaven, the site was treated with repeated applications of a wetlands-approved herbicide in order to discourage re-growth.
Due to the propensity of sites within the San Timoteo Creek region to become re-colonized with invasives including perennial pepperweed (Lepidium latifolium) and black mustard (Brassica nigra), the District implemented an active revegetation plan for the removal site. The District’s Field Ecologist propagated cuttings of native riparian species including a mix of willows including arroyo (Salix lasiolepis), narrow-leafed (Salix exigua), and red (Salix laevigata), and the shrub mulefat (Baccharis salicifolia). The cuttings were planted on a north-facing slope on the former removal site, and were installed in the winter of 2009 in order to maximize the chances of individual survival. Thus far, the field ecologist has document an approximately 71% survival rate, as 57 out of the 80 cuttings installed have survived. In 2010, the field ecologist will install additional cuttings of California wild rose (Rosa californica) and California blackberry (Rubus ursinus), which are already being propagated off-site.
Currently, the District is monitoring the site to ensure continued success of plantings, and will consider installation of temporary irrigation, if necessary. The presence of the natives thus far seems to be acting as a deterrent to the reappearance of invasive vegetation, which bodes well for the overall restoration effort at this site.