Difference between revisions of "Arundo donax in California's Central Coast Region"
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''Arundo donax'' grows in large clustered patches, competing with native species such as willows, mulefat, and cottonwoods, reducing wildlife habitat for a range of native and migratory species<ref name="Arundo Growth"> </ref>. As Arundo spreads individual clusters become interconnected, producing a monoculture cane wall
''Arundo donax'' grows in large clustered patches, competing with native species such as willows, mulefat, and cottonwoods, reducing wildlife habitat for a range of native and migratory species<ref name="Arundo Growth"> </ref>. As Arundo spreadsindividual clusters become interconnected, producing a monoculture cane wall stifles the growth of indigenous riparian species <ref name="Arundo Growth"> </ref>. In addition to providing minimal nutritional values and insufficient habitat structure, Arundo the production on aerial insects, which could have serious implications for many of [[California's Threatened Species | California's already threatened insectivorous bird populations]], such as the least Bell’s vireo (Vireo bellii pusillus) and southwestern willow flycatcher (Empidonax traillii extimus).
==Local Solutions to Arundo Invasion==
==Local Solutions to Arundo Invasion==
Revision as of 10:27, 10 April 2018
- 1 Arundo donax: Invasive Plant
- 2 Arundo donax in the Central Coast
- 3 Local Solutions to Arundo Invasion
- 4 Future of Arundo
- 5 References
- 6 Links
- 7 Disclaimer
Arundo donax: Invasive Plant
Giant reed (Arundo donax) is a perrenial invasive grass native to Eastern Asia. It is a persistent rhizomatous grass with a high biomass production and was introduced around the world as a building material . When healthy, this grass can reach up to 20 feet in height with long, flat, green leaves. It is considered an ecological threat since it spreads when its rhizomes come in contact with soil within wetlands. This grass spreads along riparian zones and lake shores, contending with native vegetation for sunlight, water, and nutrients .
Arundo donax in the Central Coast
Arundo donax (Arundo) was orginally introduced in California during the 1820's as an erosion control agent in an effort to maintain stream bank stability along drainage channels. Since it introduction, this reed has been spreading through Central California watersheds, and exacerbating flood prone areas . Monterey and San Luis Obispo counties, as well as the San Francisco Bay, Sacramento and San Joaquin Rivers have been impacted by proliferating stands of Arundo . Arundo overgrowth can alter the direction of water flow, influence the force of the river, and increase the risk of flooding. Thick patches of Arundo can obstruct the natural flow of a river, forcing water to find an alternative pathway, potentially impacting neighboring farmland and private properties . High areas of biomass also increases the risk and severity of fires in these riparian zones, endangering native plants, and other species that find habitat in this area .Approximately 1,900 acres of the 4,160 sq miles of the Salinas Watershed was encroached with Arundo by 2008, before control programs were set in place to treat the stands along the Salinas River (Figure 2) . After the implementation of control programs, approximately 1,400 acres of Arundo remain in 2017 (pers. comm., E. Zefferman, RCDMC).
Flooding in Central Coast
The Salinas River has a long history of floods dating back to 1911, with the most recent flooding forecasted in February of 2017, after heavy rains . With high precipitation rates in the area in the winter, proliferating Arundo stalks are further exacerbating flood risks in this region.
Arundo donax grows in large clustered patches, competing with native species such as willows, mulefat, and cottonwoods, reducing wildlife habitat for a range of native and migratory species. As Arundo spreads, individual clusters become interconnected, producing a monoculture cane wall that stifles the growth of indigenous riparian species . In addition to providing minimal nutritional values and insufficient habitat structure, Arundo also limits the production on aerial insects, which could have serious implications for many of California's already threatened insectivorous bird populations, such as the least Bell’s vireo (Vireo bellii pusillus) and southwestern willow flycatcher (Empidonax traillii extimus).
Local Solutions to Arundo Invasion
The two groups that are addressing this encroachment of Arundo in the Central Coast region are the Resource Conservation District, Monterey County (RCDMC), and the Monterey County Water Resources Agency (MCWRA) . The Monterey County Agricultural Commissioner began treating the Arundo by implementing spraying of scattered patches in the upper watershed (pers. comm., E. Zefferman, RCDMC). In 2011 the California Invasive Plant Council (CalIPC) prepared an Arundo donax Distribution and Impact Report in agreement with the State Water Resources Control Board (SWRCB) (Table 1) .
The following table was extracted from the CalIPC Arundo donax Distribution and Impact Report of 2011 . This document was submitted to the State Water Resources Control Board (SWRCB), summarizing details of the species encroachment spanning from Northern California to Tijuana. The highest levels of invasion along the Salinas River have been observed in vegetated floodplains, vegetated low terraces, and vegetated upper terraces, similar to San Luis Rey, Santa Ana, Santa Clara, Santa Margarita, and Ventura River. This document also provides a comparison of Arundo distribution in various watersheds. For example, in the Salinas watershed Arundo patches are less continuous and lack the connectivity often displayed in other impacted watersheds across the state .
|Table 1. Arundo acreage in central California by hydrologic unit according to 2011 Distribution and Impact Report .|
|Hydrological Unit||Total Area (Acres)||Treated Arundo (Acres)||Untreated Arundo||Total Arundo||Percent Treated|
In 2014 the RCDMC took over the responsibility of maintaining Arundo growth in Monterey County, which they began by conducting an initial study in accordance with the California Environmental Quality Act (CEQA), detailing the current extant of the problem in the Salinas Watershed. The Initial Study resulted in a Mitigated Negative Declaration submitted to the California Department of Fish and Wildlife (CDFW) for the Salinas River Watershed Invasive Weed Control and Restoration Program, which is currently being implemented by the RCDMC in collaboration with the CalIPC .
The Streambed Alteration Agreement under the Initial Study clearly outlines restriction regarding the "take" of any threatened species including the San Joaquin Kit Fox, South-Central California Coast Steelhead, Monterey roach, Tidewater Goby, California Red-Legged Frog, sensitive plant species, California Tiger Salamander, Western Spadefoot, Pacific Pond Turtle and Foothill Yellow-legged Frog, Burrowing Owl, Least Bell's Vireo, and the American Badger. Mitigate measures were implemented throughout the duration of the project to avoid take of the previously stated threatened species, as well as any addition fish or wildlife that could may be affected during Arundo removal.
Removal efforts also take the protection of native plant species into consideration when implementing mitigative strategies to remove Arundo from riparian corridors. Species specific herbicides are used when possible to avoid broad spectrum eradication. After removal of Arundo, native plants, such as willows and the California sycamore, are restored in regions that are prone to erosion in an effort to maintain stream bank stability . The rest of treated riparian areas are naturally restored (pers. comm., E. Zefferman, RCDMC). With erosion as a concern before and after Arundo control treatment around the Salinas River, the Initial Study also limits vehicular operations for up to 24 hours after large rain events that would make riparian region soil more prone to erosion.
Arundo Control Methods
Within the Arundo Control Program, the RCDMC uses these methods of control . :
- Chemically treat with broad-spectrum and target-species specific herbicides including glyphosate, imazapyr, or triclopyr, and will be formulated for approved use nar water bodies using backpack sprayers or hand-held power sprayers .
- Removal of dead stands by mowing with attachments, by hand and carried to chippers
Future of Arundo
Since the Salinas River watershed has the second-largest infestation of California, RCDMC has implemented the Arundo Control Program in 2008, to control all Arundo by the year 2028 . Many stakeholders have been collaborating with RCDMC and private landowners in Monterey County, in order to restore native riparian vegetation. The RCDMC Control Program has been successful and treated a significant amount of Arundo since 2008 and bettered the river system with the help of private landowners, as seen in Table 2.
|Table 2. Acerage of Treated Arundo in Salinas River Watershed (pers. comm., E. Zefferman, RCDMC)|
|Year||Acerage of Arundo Treated|
Satellite Images of Salinas River Land Cover 
As seen in these Landsat 8 satellite land cover images, the Arundo invasion is under control since the start of the control programs.
- / CALIPC (California Invasive Plant Council). Arundo donax. Cal-IPC.
- / Pilu R, Bucci F, Badone FC, Landoni M. 2012. Giant reed (Arundo donax L.): A weed plant or a promising energy crop? African Journal of Biotechnology 11(38) 9163-9174.
- / Swearingen J, Bargeron C. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health.
- / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.
- Biology and growth habits of giant reed (Arundo donax).
- / Wessel, Lindzi. 2016. Arundo: The invasive 'hair clog' of the Salinas River. The Californian..
- / Spencer DF, Colby L, Norris GR. 2013. An evaluation of flooding risks associated with giant reed (Arundo donax). Journal of Freshwater Ecology 28(3) 397-409.
- / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. .
- / Wright, T. 2017. Forecast calls for flooding on Salinas River this weekend. Santa Cruz Sentinel Weather.
- / CALIPC (California Invasive Plant Council). 2011. Arundo donax Distribution and Impact Report. State Water Resources Control Board.
- / RCDMC (Resource Conservation District, Monterey County). 2014. Attachment E-Regulatory Documentation. Salinas River Watershed Invasive Weed Control and Restoration Program. RCDMC.
- "Salinas River." 36°21'45.24"N and 121°13'53.24"W. Google Earth. 4/2015 and 10/2016. April 5, 2018.
- Monterey County Water Resources Agency (MCWRA)
- State Water Resources Control Board (SWRCB)
- California Environmental Quality Act (CEQA)
- Resource Conservation District, Monterey County (RCDMC)
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