Difference between revisions of "Arundo donax in California's Central Coast Region"

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(Considerations / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. . .)
(Mitigation Measures / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. . .)
 
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==''Arundo donax'': Invasive Plant==
 
==''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 <ref name="pilu"> [http://www.academicjournals.org/article/article1381136031_Pilu%20et%20al.pdf / 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.]</ref>. 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 <ref name="atlas">[https://www.invasiveplantatlas.org/subject.html?sub=3009 / Swearingen J, Bargeron C. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health.] </ref>.
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Giant reed (''Arundo donax'') is a perrenial [[Invasive Species of California|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 <ref name="pilu"> [http://www.academicjournals.org/article/article1381136031_Pilu%20et%20al.pdf / 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.]</ref>. 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 <ref name="atlas">[https://www.invasiveplantatlas.org/subject.html?sub=3009 / Swearingen J, Bargeron C. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health.] </ref>.
  
 
==''Arundo donax'' in the Central Coast==
 
==''Arundo donax'' in the Central Coast==
 
[[File:arundo-infestation-within-the-salinas-river-watershed.jpg|350px|thumb|Figure 2: Encroachment of ''Arundo donax'' along Salinas River. Map by DENDRA Inc. <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>.]]
 
[[File:arundo-infestation-within-the-salinas-river-watershed.jpg|350px|thumb|Figure 2: Encroachment of ''Arundo donax'' along Salinas River. Map by DENDRA Inc. <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>.]]
''Arundo donax'' (Arundo) has been spreading through Central California watersheds, and exacerbating flood prone areas  <ref name="calif">[https://www.thecalifornian.com/story/news/local/2016/03/04/arunda-river-runs/81345194 / Wessel, Lindzi. 2016. Arundo: The invasive 'hair clog' of the Salinas River. The Californian.]. </ref>. [[Monterey]] and [[San Luis Obispo County| San Luis Obispo]] counties, as well as the [[San Francisco | San Francisco Bay]], Sacramento, and San Joaquin Rivers have been impacted by proliferating stands of Arundo <ref name="calif">[https://www.thecalifornian.com/story/news/local/2016/03/04/arunda-river-runs/81345194 / Wessel, Lindzi. 2016. Arundo: The invasive 'hair clog' of the Salinas River. The Californian.]. </ref>. 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 <ref name="spencer"> [https://www.tandfonline.com/doi/abs/10.1080/02705060.2013.769467 / 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.] </ref>.
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''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<ref name="Arundo Growth">[https://www.water.ca.gov/LegacyFiles/irwm/grants/docs/Archives/Prop84/Submitted_Applications/P84_Round2_Implementation/County%20of%20Ventura%20(201312340014)/Attachment%208%20(cont)%20-%20Att8_IG2_BenCost_7of7.pdf Gary P. Bell, Biology and growth habits of giant reed (Arundo donax)] </ref>. Since it introduction, this reed has been spreading through Central California watersheds, affected areas such as [[Monterey]] and [[San Luis Obispo County| San Luis Obispo]] counties, as well as the [[San Francisco | San Francisco Bay]], Sacramento and San Joaquin Rivers <ref name="calif">[https://www.thecalifornian.com/story/news/local/2016/03/04/arunda-river-runs/81345194 / Wessel, Lindzi. 2016. Arundo: The invasive 'hair clog' of the Salinas River. The Californian.]. </ref>. By 2008, approximately 1,900 acres of the 4,160 sq miles of the Salinas Watershed was encroached with Arundo, before control programs were set in place to treat the stands along the [[Salinas River]] (Figure 2) <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. After the implementation of control programs, approximately 1,400 acres of Arundo remain in 2017 (pers. comm., E. Zefferman, RCDMC). 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 <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>. The Salinas watershed Arundo patches are less continuous and lack the connectivity often displayed in other impacted watersheds across the state <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.
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 <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>.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) <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. After the implementation of control programs, approximately 1,400 acres of Arundo remain in 2017 (pers. comm., E. Zefferman, RCDMC).
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Without the application of removal effects Arundo growth will continue unimpeded, contributing to the negative effects associated with excessive plant growth along riparian corridors, including flooding, fires, and habitat loss.
  
 
===Flooding in Central Coast===
 
===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 <ref name="wright"> [http://www.santacruzsentinel.com/article/NE/20170215/NEWS/170219826 / Wright, T. 2017. Forecast calls for flooding on Salinas River this weekend. Santa Cruz Sentinel Weather.] </ref>. With high precipitation rates in the area in the winter, proliferating Arundo stalks are further exacerbating flood risks in this region.
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The Salinas River has a long history of floods dating back to 1911. The growth of Arundo can exacerbate these effects by altering the direction of water flow and influencing river discharge. 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 <ref name="spencer"> [https://www.tandfonline.com/doi/abs/10.1080/02705060.2013.769467 / 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.] </ref>.
  
===Habitat===
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===Fires===
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High areas of biomass also increases the risk and severity of fires along riparian corridors<ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey]</ref>.
 +
 
 +
===Habitat Loss===
 +
As ''Arundo donax'' spreads, individual clusters become interconnected, producing a monoculture cane wall that stifles the growth of  indigenous riparian species <ref name="Arundo Growth"> </ref>. Arundo 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>. In addition to providing minimal nutritional values and insufficient habitat structure, Arundo also limits the production of aerial insects, causing serious implications for many of [[Special Status Animals in the Central Coast Region | California's already threatened insectivorous bird populations]], such as the Least Bell’s vireo (Vireo bellii pusillus) and southwestern willow flycatcher (Empidonax traillii extimus)<ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.
  
 
==Local Solutions to Arundo Invasion==
 
==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)]] <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. 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) <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.  
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The two groups that are addressing the encroachment of Arundo in the Central Coast region are the [[Resource Conservation District of Monterey County (RCDMC)]], and the [[Monterey County Water Resources Agency (MCWRA)]] <ref name="rcdmc">[https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. 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)]]<ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.
 
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===Summary Table===
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The following table was extracted from the CalIPC ''Arundo donax'' Distribution and Impact Report of 2011 <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>. 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 <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.
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{| border="4"
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! style="background: #efefef;" colspan = "6" | Table 1. Arundo acreage in central California by hydrologic unit according to 2011 Distribution and Impact Report <ref name="calipc2"> [http://www.cal-ipc.org/wp-content/uploads/2017/11/Arundo_Distribution_Impact_Report_Cal-IPC_March-2011_small.pdf / CALIPC (California Invasive Plant Council). 2011. ''Arundo donax'' Distribution and Impact Report. State Water Resources Control Board.] </ref>.
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|-
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!scope = "col" width = "150"| Hydrological Unit
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!scope = "col" width = "150"|  Total Area (Acres)
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!scope = "col" width = "150"| Treated Arundo (Acres)
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!scope = "col" width = "150"| Untreated Arundo
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!scope = "col" width = "150"| Total Arundo
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!scope = "col" width = "150"| Percent Treated
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|-
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!| Salinas
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!| 2,272,492
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!| 106.4
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!| 1,225.3
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!| 1,331.7
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!| 8%
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|}
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+
  
 
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 <ref name="run">[http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / RCDMC (Resource Conservation District, Monterey County). 2014. Attachment E-Regulatory Documentation. Salinas River Watershed Invasive Weed Control and Restoration Program. RCDMC.] </ref>.
 
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 <ref name="run">[http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / RCDMC (Resource Conservation District, Monterey County). 2014. Attachment E-Regulatory Documentation. Salinas River Watershed Invasive Weed Control and Restoration Program. RCDMC.] </ref>.
 
===Considerations <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>.===
 
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.
 
 
Since Arundo tends to encroach in riparian zones with native plants, methods of removal will ensure avoiding natives. Species specific herbicides will be used when possible to avoid broad spectrum eradication. After removal of Arundo, native plants like willow and California sycamore are restored in regions that are prone to erosion <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>. 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 lists vehicular operations to be postponed 24 hours after large rain events that would make riparian region soil more prone to erosion
 
  
 
===Arundo Control Methods===
 
===Arundo Control Methods===
Within the Arundo Control Program, the RCDMC uses these methods of control <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>. :
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As stated in the Salinas River Watershed Invasive Weed Control & Restoration Program<ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ] </ref>, the RCDMC uses the following methods of control the
 +
regional spread of Arundo:
  
 
* 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 <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>.
 
* 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 <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>.
  
 
*Removal of dead stands by mowing with attachments, by hand and carried to chippers
 
*Removal of dead stands by mowing with attachments, by hand and carried to chippers
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 +
===Mitigation Measures <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>.===
 +
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 in California's Central Coast Region|California Tiger Salamander]], Western Spadefoot, Pacific Pond Turtle and Foothill Yellow-legged Frog, Burrowing Owl, Least Bell's Vireo, and the American Badger. Mitigation measures are 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 <ref name="SAA"> [http://www.rcdmonterey.org/pdf/RCDMontereyCo%20Salinas%20River%20Arundo%20RFP%2010sept2014_AttD.pdf / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey. ]. </ref>. 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.
  
 
==Future of Arundo==
 
==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 <ref name="rcdmc"> [https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. 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.  
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Since the Salinas River watershed has the second-largest infestation of California, RCDMC has implemented the Arundo Control Program since 2014, to control all Arundo by the year 2028 <ref name="rcdmc"> [https://www.rcdmonterey.org/salinas-river-arundo-and-tamarisk-control / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.] </ref>. 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 2014 and bettered the river system with the help of private landowners, as seen in Table 2. As on April 2020, RCDMChas initiated treatment on approximately 650 acres. Private landowners have initiated treatment on almost 100 acres under the Salinas River Maintenance Program.  
  
 
{| border="4"
 
{| border="4"
! style="background: #efefef;" colspan = "2" |Table 2. Acerage of Treated Arundo in Salinas River Watershed (pers. comm., E. Zefferman, RCDMC)
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! style="background: #efefef;" colspan = "2" |Table 2. Initial Acerage of Treated Arundo in Salinas River Watershed per Year (pers. comm., E. Zefferman, RCDMC)
 
|-
 
|-
 
! style="background: #efefef;" colspan="1"  | Year
 
! style="background: #efefef;" colspan="1"  | Year
Line 75: Line 59:
 
|}
 
|}
  
===Satellite Images of Salinas River Land Cover <ref name="google"> "Salinas River."  36°21'45.24"N and 121°13'53.24"W. Google Earth. 4/2015 and 10/2016. April 5, 2018. </ref>===
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===Satellite===
 
As seen in these Landsat 8 satellite land cover images, the Arundo invasion is under control since the start of the control programs.
 
As seen in these Landsat 8 satellite land cover images, the Arundo invasion is under control since the start of the control programs.
  

Latest revision as of 10:23, 12 April 2020

Figure 1: Arundo donax (giant reed). [1].

An environmental summary created by the ENVS 560/L Watershed Systems class at CSUMB.

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 [2]. 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 [3].

Arundo donax in the Central Coast

Figure 2: Encroachment of Arundo donax along Salinas River. Map by DENDRA Inc. [4].

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[5]. Since it introduction, this reed has been spreading through Central California watersheds, affected areas such as Monterey and San Luis Obispo counties, as well as the San Francisco Bay, Sacramento and San Joaquin Rivers [6]. By 2008, approximately 1,900 acres of the 4,160 sq miles of the Salinas Watershed was encroached with Arundo, before control programs were set in place to treat the stands along the Salinas River (Figure 2) [4]. After the implementation of control programs, approximately 1,400 acres of Arundo remain in 2017 (pers. comm., E. Zefferman, RCDMC). 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 [7]. The Salinas watershed Arundo patches are less continuous and lack the connectivity often displayed in other impacted watersheds across the state [7].

Without the application of removal effects Arundo growth will continue unimpeded, contributing to the negative effects associated with excessive plant growth along riparian corridors, including flooding, fires, and habitat loss.

Flooding in Central Coast

The Salinas River has a long history of floods dating back to 1911. The growth of Arundo can exacerbate these effects by altering the direction of water flow and influencing river discharge. 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 [8].

Fires

High areas of biomass also increases the risk and severity of fires along riparian corridors[9].

Habitat Loss

As Arundo donax spreads, individual clusters become interconnected, producing a monoculture cane wall that stifles the growth of indigenous riparian species [5]. Arundo 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[5]. In addition to providing minimal nutritional values and insufficient habitat structure, Arundo also limits the production of aerial insects, causing 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)[7].

Local Solutions to Arundo Invasion

The two groups that are addressing the encroachment of Arundo in the Central Coast region are the Resource Conservation District of Monterey County (RCDMC), and the Monterey County Water Resources Agency (MCWRA) [4]. 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)[7].

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 [10].

Arundo Control Methods

As stated in the Salinas River Watershed Invasive Weed Control & Restoration Program[9], the RCDMC uses the following methods of control the regional spread of Arundo:

  • 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 [9].
  • Removal of dead stands by mowing with attachments, by hand and carried to chippers

Mitigation Measures [9].

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. Mitigation measures are 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 [9]. 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.

Future of Arundo

Since the Salinas River watershed has the second-largest infestation of California, RCDMC has implemented the Arundo Control Program since 2014, to control all Arundo by the year 2028 [4]. 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 2014 and bettered the river system with the help of private landowners, as seen in Table 2. As on April 2020, RCDMChas initiated treatment on approximately 650 acres. Private landowners have initiated treatment on almost 100 acres under the Salinas River Maintenance Program.

Table 2. Initial Acerage of Treated Arundo in Salinas River Watershed per Year (pers. comm., E. Zefferman, RCDMC)
Year Acerage of Arundo Treated
2014 113
2016 103
2017 120

Satellite

As seen in these Landsat 8 satellite land cover images, the Arundo invasion is under control since the start of the control programs.

References

  1. / CALIPC (California Invasive Plant Council). Arundo donax. Cal-IPC.
  2. / 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.
  3. / Swearingen J, Bargeron C. 2016. Invasive Plant Atlas of the United States. University of Georgia Center for Invasive Species and Ecosystem Health.
  4. 4.0 4.1 4.2 4.3 / RCDMC (Resource Conservation District of Monterey County). Salinas River Arundo and Tamarisk Control. Salinas River Watershed Arundo Control Program.
  5. 5.0 5.1 5.2 Gary P. Bell, Biology and growth habits of giant reed (Arundo donax)
  6. / Wessel, Lindzi. 2016. Arundo: The invasive 'hair clog' of the Salinas River. The Californian..
  7. 7.0 7.1 7.2 7.3 / CALIPC (California Invasive Plant Council). 2011. Arundo donax Distribution and Impact Report. State Water Resources Control Board.
  8. / 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.
  9. 9.0 9.1 9.2 9.3 9.4 / CDFW (California Department of Fish and Wildlife. 2014. Notice of Determination. Salinas Watershed Invasive Non-Native Plant Control (Project). RCD Monterey
  10. / RCDMC (Resource Conservation District, Monterey County). 2014. Attachment E-Regulatory Documentation. Salinas River Watershed Invasive Weed Control and Restoration Program. RCDMC.

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