United States Department of Environmental Agriculture Forest Assessment Service September 2015 Angeles National Forest and San Gabriel Mountains National Monument Plan for Invasive Plants Los Angeles and San Bernardino Counties, California For Information Contact: Janet Nickerman Project Lead, Angeles National Forest (626) 353-8439 The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual’s income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) 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Environmental Assessment Invasive Plant Treatment Project Table of Contents Chapter 1 - Introduction ................................................................................................................... 4 Chapter 2 - Alternatives, including the Proposed Action ................................................................. 9 Chapter 3 - Affected Environment and Environmental Consequences .......................................... 38 Human Health and Safety .......................................................................................................... 40 Invasive Plants and Native Vegetation ...................................................................................... 43 Special Status Plants .................................................................................................................. 42 Wildlife ...................................................................................................................................... 49 Soils and Hydrology .................................................................................................................. 59 Special Land Designations (Wilderness and Research Natural Areas) ...................................... 62 Recreation and Scenic Resources .............................................................................................. 67 Consequences Relative to Significance ..................................................................................... 71 Chapter 4 – List of agencies and persons consulted ....................................................................... 74 References ...................................................................................................................................... 76 Appendix A Summary of Public Comments .................................................................................. 81 Appendix B Additional Invasive Plant information ....................................................................... 87 Appendix C Potential Treatment Prescription Options .................................................................. 94 Appendix D Monitoring Plan ....................................................................................................... 100 Appendix E Projects, Activities and Factors Considered in Cumulative Effects……………….128 List of Figures Figure 1. Project Area Map. ........................................................................................................... 15 List of Tables Table 1. Summary of Proposed Treatment Methods. ..................................................................... 12 Table 2. Priority Treatment Areas and Projects ............................................................................. 16 Table 3. Comparison of Alternatives…………………………………………………………….36 Table 4. Summary of hazard indicators and toxicity categories for pesticides……………..........41 Table 5. Signal Word used for each acute toxicity category..........................................................41 Table 6. Approximate acres by vegetation type within the project area ………….……….42 Table 7. Response to Comments……………………..……………………………….………….81 Table 8. Invasive plants known to occur in and near the project area............................................88 Table 9. Some invasive species reproductive and dispersal mechanisms………………….…….90 Table 10. Potential Treatment Prescription Options..……………………………………….……94 Table 11.Projects, Activities and Factors Considered for Cumulative Effects………………….128 j iii Environmental Assessment Invasive Plant Treatment Project CHAPTER 1 - INTRODUCTION Background _____________________________________ Executive Order 13112 defines invasive plants as “non-native plants whose introduction does, or is likely to, cause economic or environmental harm or harm to human health” (http://ceq.hss.doe.gov/nepa/regs/eos/eo13112.html). Some invasive plants can change ecosystem processes such as hydrology, fire regimes, and soil chemistry. These invasive plants have a competitive advantage because they are no longer controlled by their natural predators, and can quickly spread out of control. They spread with no consideration for land ownership boundaries. Furthermore, invasive plants that grow along stream channels can easily and often increase their infestation because their seeds, effortlessly, are capable of traveling downstream. In California, approximately 3 percent of the plant species growing in the wild are considered invasive, but they inhabit a much greater proportion of the landscape (Cal-IPC). The purpose of this environmental assessment is to assess the environmental effects of invasive weed treatment in Angeles National Forest and San Gabriel Mountains National Monument watersheds, both on and off Forest and Monument lands. This proposed action will address areas not previously covered by the Invasive Plant Treatment Project, Santa Clara Watershed, Santa Clara/Mojove River Ranger District (ANF 2013) or the Invasive Plant Treatment Project, San Gabriel District (ANF 2011). These decision documents have completed evaluation for invasive weed treatments on Forest Service lands in the Santa Clara Watershed: Gorman, Liebre Gulch, Piru, Castaic, Fish Canyon, Elizabeth Lake Canyon, San Francisquito, Bouquet, Mint Canyon, Agua Dulce, Sand Canyon, Arrastre, and Aliso. The Invasive Plant Treatment Project, San Gabriel District covers the majority of the main drainages on the San Gabriel River Ranger District and San Dimas Experimental Forest (i.e., San Gabriel, Big and Little Dalton, San Dimas drainages), 350ft to either side of the high-water mark. If the invasive species are left unchecked, the ecosystems within the project area will dramatically change. Invasive plants create a host of adverse environmental effects, including displacement of native plants and reduction in habitat and forage for wildlife (including federally listed threatened and endangered, and Forest Service sensitive1 species); reduction in water quantity; potential reduction in soil productivity; and potential increase in the intensity and frequency of wildfires. After wildfires, non-native plant species typically re-establish more rapidly than native plants, suppressing the recovery of the native vegetation and allowing the invasive plants to expand their range. In addition, when wildfires occur too frequently (tamarisk and arundo-dominated communities experience higher fire frequencies than native riparian communities), some native vegetation loses the ability to recover, effectively converting high diversity native plant communities into low diversity non-native plant communities. The Angeles National Forest Land Management Plan (Forest Plan) states, “….some of the greatest threats to riparian and aquatic habitats are from the invasion of non-native plant species, particularly tamarisk, arundo, and cape ivy within the stream channels….” (Forest Plan, part 1, p. 41; USFS 2005). The Federal Noxious Weed Act of 1974 (7 USC 214), Section 15, requires federal land management agencies to develop and establish a management program for control of undesirable plants that are classified under state or federal law as undesirable, noxious, harmful, injurious or poisonous on federal lands under the agency’s jurisdiction (7 USC 2814[a]). The Act also requires the federal land management agencies to enter into cooperative agreements to coordinate the management of 4 Environmental Assessment Invasive Plant Treatment Project undesirable plant species on federal lands where similar programs are being implemented on state and private lands in the same area (7 U.S.C. 2814[c]). The Wyden Amendment (Public Law 105-277, Section 323 as amended by Public Law 109-54, Section 434) authorizes the Forest Service to enter into cooperative agreements to benefit resources within watersheds on National Forest System lands. Agreements may be with willing federal, tribal, state, and local governments, private and nonprofit entities, and landowners to conduct activities on public or private lands for the protection, restoration, and enhancement of fish and wildlife habitat and other resources; reduction of risk for natural disaster where public safety is threatened; or a combination of both. Executive Order 13112