Control of Invasive Species (2006)

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110 help direct management. Still other useful information can only be gathered on site and will be specific to your own problem situation. Information that will help staff to iden- tify the target species may include: • Common and scientific name • Picture (as a young plant and in full seed/flower)— note if easily confused with others • Annual or perennial • Growth form and habits • How tall the weed grows • Timing of flowering or seed setting, which varies with latitude • Distribution, geographical origin, and site preferences. Life-cycle and lifespan information also helps determine proper treatment methods. Perennial weeds store nutrients underground and can access these reserves to resprout repeatedly. Maintenance staff may find the following valu- able in determining appropriate treatment: • How does the weed reproduce? If the weed spreads by seeds, note the flowering time, because control mea- sures will usually occur before the flowers produce seeds to prevent another seed crop. Are a large num- ber of seeds produced? • What is the mechanism(s) of seed dispersal and how can it be reduced? Also important are any special challenges the species presents in attempting to manage or control it. Knowing such challenges helps the design, construction, or mainte- nance manager to plan accordingly. For example, all inva- sives tend to have seeds that remain viable in the soil for many years. • Can one small fragment regenerate an entire plant? • Is the target weed found in sensitive areas such as wetlands or streamsides where treatment methods are limited? • Is the weed resistant to certain types of control methods? • Who are the people and the agencies that are con- cerned about this weed? • What is the natural history of the site you are trying to manage (soil type, amount of rainfall, species of ani- mals, and competitive vegetation present)? • How is the land being used (present and future plans) and what is the history of land use? • What is the history of weed control on the site? • Is this a recent invasion or an old problem? One of the best overviews of Integrated Vegetation Management (IVM) plan components is a series of tech- nical bulletins developed as a resource for vegetation managers seeking practical information on effective, environmentally sound methods for managing invasive species. The series was authored by the Bio-Integral Resource Center (BIRC) through a U.S. Environmental Protection Agency (EPA) grant. These bulletins have been published on the Internet at IPM Access through a separate EPA grant as a result of the EPA’s interest in this type of information being made freely available to a wider audience. The following sections, addressing the principle components of IVM programs, are adapted from that resource: • Gathering background information and conducting weed inventories. • Setting management objectives. • Establishing monitoring programs to inventory weed growth stages, locations, and acreage infested. • Setting treatment action levels and treatment thresh- olds to determine if treatment is necessary. • Using weed prevention measures and revegetation in your management plan. • Applying effective, least-toxic management methods. • Educating the public. • Evaluating the program. The goal of an IVM or Integrated Roadside Vegetation Management (IRVM) program is to keep noxious weed populations low enough to prevent unacceptable spread, damage, or annoyance, and to encourage desirable vegeta- tion to permanently replace the weeds. Treatment occurs only when monitoring indicates thresholds have been reached and treatment is necessary. Several methods are selected from educational, biological, cultural, manual, mechanical, and least-toxic chemical control tactics and then integrated into a treatment program. IVM emphasizes revegetation with desirable plant species, as well as other actions that will prevent future weed infestations. When applied appropriately, the IVM process results in improved management, lower cost, greater ease of main- tenance, and lower environmental impacts from control activities. GATHERING BACKGROUND INFORMATION ON TARGET INVASIVES Gathering as much information as possible about the biol- ogy and growth patterns of the target weed can assist and APPENDIX D Overview of Common Integrated Roadside Vegetation Management or Integrated Vegetation Management Steps

111 UNDERSTAND DAMAGE OR POTENTIAL THREAT The damage caused to native plant communities by invasive species is extensive. Not only do weeds directly compete with native species for space, light, moisture, and nutrients, but they also have the ability to physically alter the structure or the nutrient cycling of a system, disrupting natural ecosys- tem function to which native communities are adapted. SET MANAGEMENT OBJECTIVES When setting management objectives, the weed manager will need to balance the resources available with the requirements of the law. The following questions may help in clarifying objectives: • What are the legal requirements? • What are the available resources (money, people, and time)? • Which control strategies are best suited to the weed I am trying to manage and the area in which it occurs? • What is the availability of biological control agents or grazing animals? • What are the environmental considerations? • What other people or agencies do I need to collaborate with? • What kind of follow-up preventive measures will need to be implemented? • What kind of public education is needed? • What is the desired level of control (see below)? Can this level be sustained by my resources? Levels of potential control include: • Containment—keeping an established population of the weed in check so that the area infested by the weed does not increase. This strategy can be employed against newly invading weeds or well-established species. It is especially useful when time and money are in short supply or when the infestation is very large. • Reduction—reducing the area covered by a weed or reducing the dominance of that weed. This strategy can also be used against new or established weeds; however, it requires more resources and more time than containment. • Eradication—completely eliminating the weed from the management area. This strategy usually consumes the greatest amount of time and resources and is applicable mainly to newly invading weeds that are confined to a limited number of small areas. SETTING TREATMENT ACTION LEVELS Sufficient resources are seldom available. Weed manage- ment is a process that continues over many years, and weed managers are continually prioritizing treatment areas and balancing the priorities with their resources. This process is called “setting treatment action levels.” When the weed population reaches an intolerable level, a department of transportation (DOT) takes action to treat it. Two situations that increase the priority of a site are (1) the discovery of a small “outlier” population, a recent inva- sion from another area that must be taken care of soon to prevent a bigger problem later, or (2) the discovery that the weed population has become a threat to agriculture, native plants, food sources for wildlife, highway safety, water resources, etc. Inevitably there are areas that are lower in priority and will be tolerated for the short term. Complete eradication may not be practical unless the patches are very small. Moreover, to maintain populations of natural ene- mies, some individual plants must be permitted to persist. Setting treatment thresholds includes prioritizing and balancing treatments with resources. Weeds will be treated when populations increase beyond a predetermined level. This level will largely depend on the characteristics of the site and weed. In some cases the level may be no weeds at all, and in other cases the number of weeds you can tolerate may be much greater. ESTABLISHING A MONITORING PROGRAM In IVM, monitoring is the repeated inspection of areas that may be subject to noxious weed problems. Written records will allow comparison of inspections over time to reveal how conditions are changing, especially whether noxious weed populations are increasing or decreasing. • Focus limited monitoring resources on sites where problems are most likely to occur. Public sightings of new weed infestations may be encouraged through an education or incentive program (see Educating Vege- tation Management Personnel and the Public). • Maintain records of your monitoring activities. Creat- ing standardized forms will make data collection easier and help remind you to gather all the information you need. Forms work best if they include labeled blanks for all pertinent information and allow the user to check or circle rather than having to write words or numbers. See examples of forms, which often include information such as the name(s) of the person(s) col- lecting the data; location and date of monitoring; a qualitative description of the vegetation, such as the names of the plants or types of plants (native vegeta- tion, annual/perennial weeds, trees, etc.) and stage of growth (germinating, flowering, setting seed, etc.); and a quantitative description, such as percent cover, den- sity, size of the patch, or, if possible, number of plants. • Note special conditions such as unusual weather events and record treatment history, including information on

Maintenance with and without Herbicides). www.wsdot. wa.gov/maintenance/vegetation/comparison.htm. • Northeastern States’ Costs of Managing Invasive Species, compiled by Ray Bouchard, Maine Depart- ment of Environmental Protection, Augusta. • “Costly Interlopers: Introduced Species of Animals, Plants, and Microbes Cost the U.S. $123 billion a Year,” Scientific American, Feb 15, 1999. • Combating the Economic and Environmental Devas- tation from Invasive Species, Western Governors’ Association, Dec. 2000. • Economic and Environmental Threats of Alien Plant, Animal, and Microbe Invasions, Cornell University, Ecosystems and Environment 84, 2001, pp. 1–20. • Evans, E.A., “Economic Dimensions of Invasive Species,” Choices Magazine: Food, Farm, and Resource Issues, June 2003. • Bergman, D.L., et al., “Economic Impact of Invasive Species to Wildlife Services’ Cooperators,” Proceed- ings of the Third National Wildlife Research Center Special Symposium: Human Conflicts with Wildlife: Economic Considerations. • McCann, J.A., L.N. Arkin, and J.D. Williams, Non- indigenous Aquatic and Selected Terrestrial Species of Florida: Status, Pathway, and Time of Introduction, Present Distribution, and Significant Ecological and Economic Effects, National Biological Service, Gainesville, Fla. • Noxious Weed Cost Share Program and ISDA 2002 Cost Share Program Accomplishments, Idaho State Department of Agriculture, Boise. • “West Nile Virus Economic Impact, Louisiana,” Emerging Infectious Diseases, Vol. 10, No. 10, Cen- ters for Disease Control and Prevention, Oct. 2004. The 2002 Outbreak of West Nile Virus Cost Louisiana $20 Million: kplctv.com/AP (Sep. 28, 2004). • “Potential Economic Losses Associated with Uncon- trolled Nutria Populations in Maryland’s Portion of the Chesapeake Bay,” Maryland Department of Nat- ural Resources, Annapolis, Nov. 2, 2004. • “The Impact of Knapweed on Montana’s Economy,” North Dakota State University Agricultural Experi- ment Station, Fargo, July 1996. • “Estimating Net Losses in Recreation Use Values from Non-Indigenous Invasive Weeds,” Special Publi- cation SP-03-10, University of Nevada–Reno, Coop- erative Extension. • “The Economic Costs of Delaying Invasive Weed Control: An Illustration Based on Nevada’s Tall Whitetop Initiative,” Special Publication SP-01-08, University of Nevada–Reno, Cooperative Extension. • “The Estimated Costs of Treating Invasive Weeds in Elko County, Nevada,” Fact Sheet FS003-41, Univer- sity of Nevada–Reno, Cooperative Extension. • “Economic Analysis of Containment Programs, Dam- ages, and Production Losses from Noxious Weeds in Oregon,” The Research Group, Corvallis, Oregon, for 112 treatment applications (who, when, where, how, cost, difficulties, and successes). This will allow you to eval- uate and fine tune treatments. Monitoring efforts should be scheduled to coincide with critical life stages of the weed or its biological controls. If possible, plan monitoring sessions alongside other sched- uled activities in the area to save time and labor. After treatment activities, and at the end of the season, schedule monitoring sessions to help you evaluate your program. EVALUATE VEGETATION MANAGEMENT PROGRAM At the end of the season, evaluate and fine-tune your program to improve it the next year. Some questions to ask at the end of the season might be (IVM Technical Bulletin, IVM Pro- gram Evaluation: members.efn.org/%7Eipmpa/noxevaluate. html). • Were the objectives of the management program met? • Were all the necessary components of the program actually developed? • Were they integrated successfully? Were the right people involved in the integration? • Which control methods seem to be working and which are not? Keep in mind that this is best answered over a span of years. • Do some of these methods need fine-tuning? • What kind of follow-up is needed next year? • How can I best communicate this information? Costs are central to a decision to continue an IVM pro- gram. It is important to keep in mind that the transition period to IVM will probably involve investing in the man- agement of infested areas to achieve stable vegetation that will reduce management costs in future years. Native plants and other beneficial vegetation take years to establish. Although you may find that total annual costs drop during the first year of IVM, it is also possible that costs may increase somewhat; however, after two or three years costs should decline and stabilize below the historical average. COST–BENEFIT INFORMATION REGARDING INVASIVE SPECIES CONTROL A number of DOTs noted that access to information about the costs and benefits of treating invasive species could bol- ster their ability to get resources allocated to address the problem. A number of states, associations, and scientific entities have begun to compile these data. • WSDOT Comparison of Roadside Maintenance Prac- tices—Impacts of Herbicide Use on Cost and Results. Management without herbicides costs roughly double. (Washington State DOT, Cost Comparison—Vegetation

113 Oregon Department of Agriculture, Plant Division, Noxious Weed Control Program, Nov. 2000. • Impacts of Aquatic Nuisance Species Within the State of New York, New York Sea Grant. • “Fire Ants Cost Texans Millions,” Texas A&M University, Department of Entomology, Apr. 21, 2000. • Invasive Non-native Species: Background and Issues for Congress (revised Nov. 25, 2002), Congressional Research Service, Washington, D.C. • “Riparian Impacts—Invasive Plants Damage Green Zones Along Rivers and Streams,” Montana Weed Control Association, Twin Bridges. • “Rocky Mt Research Station: Foreign Weeds Feed Western Fires,” Newspaper article on the problem of invasive plants and possible solutions, from the U.S. Forest Service. • “The Spread of Invasive Weeds in Western Wild- lands: A State of Biological Emergency,” The Gover- nor’s Idaho Weed Summit, from the Bureau of Land Management. • Weed Control on Conservation Reserve Program (CRP) Acres, Establishing Perennial Grasses on Former Cropland Presents a Challenge—weed con- trol can be accomplished with herbicides, tillage, burning, mowing, and crop competition. The key to weed control is timeliness; from the University of Nebraska–Lincoln. • Invasive Weeds in Rangelands: Species, Impacts, and Management—Rangeland and pastures comprise about 42% of the total land area of the United States. This abstract describes the effects found of more than 300 rangeland weeds in the United States, which cause an estimated loss of $2 billion annually, affect- ing the livestock industry, interfering with grazing, poisoning animals, increasing costs of managing and producing livestock, and reducing land value. Weed Science Society of America. • Knapweed—Its cost to British Columbia (BC)—Sev- eral aspects of how knapweed (both diffuse knapweed (Centaurea diffusa) and spotted knapweed (Centaurea biebersteinii) infestations are causing major environ- mental deterioration and loss of beef production in the southern interior of British Columbia. BC Ministry of Agriculture, Food, and Fisheries.