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Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin (2023)

Chapter: Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides

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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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Suggested Citation:"Chapter 10: Cost-Benefit Considerations for Pollinator Management on Roadsides." National Academies of Sciences, Engineering, and Medicine. 2023. Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin. Washington, DC: The National Academies Press. doi: 10.17226/27061.
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10-1 Chapter 10 Cost-Benefit Considerations for Pollinator Management on Roadsides 10.1 Introduction   The relative costs and benefits of maintaining existing or establishing new pollinator habitat along roadsides are important considerations when incorporating Endangered Species Act (ESA) compliance, species conservation, and habitat management into transportation planning, design, construction, and maintenance. As has been demonstrated throughout this guide, there are many opportunities to benefit pollinators and contribute to the recovery of listed and imperiled species through changes in roadside management. Many of these changes may have a relatively minor effect on costs, and those that are more costly can often lead to long-term cost savings, while having important substantial benefits for imperiled pollinators and the pollinator community in general. Furthermore, the benefits can extend well beyond the pollinator community. For example, roadsides managed for pollinators by planting beneficial plants and reducing mowing can broadly benefit wildlife and ecosystem health, and are also an opportunity to showcase natural beauty and promote tourism, reduce maintenance (a cost savings to departments of transportation [DOTs]), and support a wide range of important ecosystem services such as carbon sequestration and erosion control. Roadsides are an integral part of the highway system and are valued by the general public as important natural and scenic resources. Therefore, it is important to consider all types of potential benefits when considering investing in pollinator-friendly roadsides. 10.2 Cost‐Benefit Analysis for Sustainability  A cost-benefit analysis is an approach to decision-making weighing the various costs of a particular action with the value of the benefits expected as an outcome of the action. Cost-benefit analyses have been used in project decision-making for many decades (Elkington 2018) and have traditionally only focused on the quantitative economic costs and benefits. More recently cost-benefit analyses have been approached from the perspective of long-term sustainability and include other non-economic factors such as societal and environmental costs and benefits. When cost and benefit considerations include environmental, societal, and economic factors they are often referred to as the triple bottom line (Figure 10-1). There are environmental, societal, and  economic benefits to managing roadsides for  pollinators. Photo Credit: Luis Colon/Arizona DOT 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-2 Figure 10-1. Objectives of a triple bottom line. The triple bottom line approach is a cornerstone of the Federal Highway Administration (FHWA) Sustainable Highways Initiative (sustainablehighways.dot.gov), which supports the U.S. Department of Transportation Strategic Plan for FY2022–2026 (USDOT 2022). The triple bottom line considers long-term sustainability and therefore long-term costs and benefits, including the full range of factors important to human quality of life. Considering the importance of pollinators to human sustenance, the triple bottom line approach is particularly relevant to cost-benefit consideration of pollinator-friendly measures. While cost-benefit analyses can be useful in the decision-making process, they can be difficult to complete. In a 2016 report to Congress, the FHWA noted that only about 10 percent of state DOTs regularly use any form of formal cost-benefit analyses (FHWA 2016), and mostly only for relatively large projects. Some of the greatest hurdles to conducting a cost-benefit analysis include the inconsistency and difficulty of obtaining quantitative cost information, lack of institutional support, and difficulty quantifying societal and environmental costs and benefits (FHWA 2016). These difficulties still hold true today.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-3 Case Study: Arizona DOT Sustainable Transportation Program: INVEST Case Studies Arizona DOT recognizes the importance of sustainability in the long-term success of the state’s transportation network, and has embraced the triple bottom line approach systematically through its administrative, planning, design, construction, operations, and maintenance activities. To achieve its ambitious sustainability goals, Arizona DOT has applied the sustainability tools of the FHWA INVEST program to a wide variety of case studies. Application of the performance measures and metrics to the three INVEST modules of system planning, project development, and operations and maintenance has helped Arizona DOT undertake cost-benefit analyses, life cycle cost analyses, and return on investment evaluations across the environmental, societal, and economic factors essential for sustainable operations and project implementation. The environmental, social, and economic benefits of this approach are carried forward into Arizona DOT projects through its Sustainable Project Development checklist, which guides project design and construction to consider project elements to optimize all three areas of sustainability, including habitat protection, and wildlife connectivity. While pollinators are not mentioned explicitly, they are an important element of the environmental and societal factors considered by the checklist. Source: Arizona DOT 2020. Given the challenges DOTs have faced in obtaining information for quantitative cost-benefit analyses, this guide proposes the application of a simple, qualitative cost-benefit tool using the triple bottom line approach that considers the environmental, societal, and economic costs, as well as benefits of, pollinator-friendly habitat. This approach can be used when making decisions about pollinator habitat during the planning, design, construction, and maintenance phases of a project. Costs are evaluated from the point of view of a state DOT. Benefits are evaluated in terms of environmental benefits (e.g., to habitat diversity and endangered species recovery), societal benefits (e.g., to crop pollination services), and operational benefits to a state DOT (e.g., operational flexibility through ESA compliance, or reduction of future risk of regulation by contributing to species recovery and avoidance of future listing). 10.2.1 Land Use Context and Variability of Costs and Benefits Not only are quantitative costs and benefits of roadside management for pollinators difficult to obtain (as mentioned above), they vary regionally and may depend on the surrounding land use, ecological context, and pollinator species of interest. It might cost more to adjust mowing schedules to accommodate a particular species of butterfly that breeds during a time when mowing is most cost efficient for a DOT, for example, or the costs of plant materials used in revegetation to support one imperiled species might be higher than the cost of plant materials to support another imperiled species. Although the upfront costs associated with the conservation of a particular species might be higher, the benefits of taking those conservation actions might also be greater. Investments made to proactively conserve a rare species, for example, can prevent state or federal listings and may reduce costs DOTs might otherwise incur in the future.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-4 The costs and benefits could also be considered in the context of the adjacent urban, agricultural, or natural land uses. For example, improving pollinator habitat on roadsides surrounded by natural habitat may seem unnecessary (providing little additional relative conservation value) if the target pollinator species has all its needs met in the adjacent habitat. On the other hand, revegetation projects in such areas may bring value by helping to reduce the spread of invasive plants to sensitive areas as well as increasing habitat connectivity. Or consider, for example, that improving pollinator habitat on roadsides adjacent to agricultural lands can provide additional pollination services, but that the particular economic benefit might be lower for roadsides adjacent to urban landscapes. However, habitat improvement actions on urban roadsides may provide the only suitable habitat for miles and can create vital connectivity between distant areas of natural habitat, bringing broader benefit and greater overall value. The relative costs and benefits of pollinator-friendly actions can also vary by region. Modification of mowing regimes in the Southeast can have substantial benefits but may not be relevant in the driest areas of the Southwest where mowing is rarely needed. A cost- benefit analysis in one region may not directly apply to another. Given the high variability of costs and benefits across species and regions and within differing land use contexts, it is difficult to provide definitive cost-benefit rules and relationships. Instead, this guide provides simple cost and benefit tools and concepts that can be applied and adapted by each DOT for the evaluation of pollinator-friendly actions being considered in project planning, design, construction, and maintenance. 10.3 Types of Costs and Benefits  10.3.1 Regulatory Costs and Benefits The primary federal regulation addressing pollinators is the ESA (see Chapter 4, Native Pollinators and the Federal Endangered Species Act: Compliance Strategies for State Departments of Transportation). Many states have similar endangered species protection acts that can also regulate pollinator species. The growing awareness of the importance of pollinators and the evidence of dramatic declines in the health and diversity of pollinator species have also led to additional state and federal regulations protecting pollinators (e.g., Maryland Pollinator Protection Act of 2016, Save Oregon’s Pollinators Act of 2014, Connecticut Pollinator Health Act of 2017). Many of these regulations focus on restricting the use of certain pesticides, some encourage or require inclusion of pollinator habitat on public lands and rights-of-way (ROWs), many require improved public and agency education of the importance of pollinators, and some provide funding incentives when pollinator-friendly measures are included in projects. The reality is that pollinators and their habitat will be more tightly regulated in the coming years, which brings potential increased costs and potential benefits. As of June 2022, there are 48 invertebrate pollinator species listed as endangered or threatened under the ESA (USFWS 2022). It is worth noting that insects are disproportionately underrepresented under the ESA; although they make up 72 percent of animal diversity, only 10.3 percent of listed species are insects (Black 2012). Figure 10-2 shows the trend in the number of all species listings over time. The number of pollinator species listed under the ESA has increased in recent years and this trend for pollinators,

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-5 and species overall, is unlikely to slow down because of ongoing factors such as loss of habitat, impacts from pesticides, and the effects of climate change. Source: USFWS 2018.   Note: Includes Threatened and Endangered listings under the 1973 ESA and its precursors.   Figure 10-2. Listings of all species under the ESA by year. As noted in Chapter 4, 75 percent of transportation planners and managers surveyed recognize the possibility that if an imperiled pollinator species in their project area became listed, it could cause barriers, such as altered project timelines, increased workloads, and higher costs to their agencies. Implementing actions to benefit unlisted pollinators and prevent them from being listed under the ESA will provide substantial long-term regulatory cost savings. Upfront planning by DOTs can result in substantial future time and cost savings as workflow is improved and the number of project redesigns and modifications to operations are reduced across their larger road network. A total of 81 percent of the surveyed transportation professionals confirmed that the risk of an imperiled pollinator species becoming listed would motivate their DOT to proactively protect pollinators in order to reduce the risk of listing. These same transportation professionals also recognized that early adoption of regulatory compliance strategies was good for public relations and consistent with identified sustainability goals for their transportation agencies. Once a species is listed, the only options are to avoid impacting the species or seeking an incidental take permit under Section 7 or 10 of the ESA, either of which can cause project delays and increase costs. However, strategic planning to comply with the ESA and other laws and regulations can reduce DOT regulatory Voluntary conservation measures to support  imperiled pollinators like the American bumble  bee (Bombus pensylvanicus) may help to  recover the species and avert a listing under  the ESA, potentially saving transportation  agencies time and money.  Photo Credit: Ray Moranz/Xerces Society 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-6 costs. Developing long-term Habitat Conservation Plans (Section 10 of the ESA) for non- federal actions or “programmatic” Section 7 permits for federal actions can provide long- term cost and time savings through increased regulatory certainty and project streamlining for large and small road projects as well as maintenance activities. Case Study: Programmatic Section 7 ESA Permits for Colorado DOT Colorado DOT developed a conservation strategy as a part of a 20-year programmatic Section 7 permitting agreement to cover 38 species, including 4 pollinators (butterflies), in the Central Shortgrass Prairie ecoregion of Colorado. The programmatic agreement and conservation strategy has three goals: 1. Proactive conservation of the declining and listed species in this ecoregion; 2. Providing mitigation for potential impacts of Colorado DOT projects within the existing transportation corridor; and 3. Improved efficiencies and cost savings for the environmental compliance of Colorado DOT project. The conservation strategy includes a range of actions to offset impacts on the covered species from Colorado DOT transportation improvement and routine maintenance, including recommended practices and land protection projects. Source: Grunau et al. 2003. Case Study: Economy of Scale: Major Improvements in Transportation Project Delivery Cost and Schedule with Long-Term Multi-Species Habitat Conservation Plan (MSHCP) In Riverside County, California, the Western Riverside MSHCP has provided substantial economic benefits to regional transportation projects. Approved in 2004, the MSHCP covers 146 species, including 2 endangered pollinators: the Delhi sands flower-loving fly (Rhaphiomidas terminatus abdominalis) and the Quino checkerspot butterfly (Euphydryas editha quino). As of March 2019, the implementing entity of the plan, the Western Riverside County Regional Conservation Authority (RCA), has compiled the following economic benefits of their plan to transportation projects, based in part on a comprehensive cost-benefit study prepared in 2008 by the Rand Corporation (Dixon et al. 2008) and 15 years of plan implementation:  The Western Riverside County MSHCP has accelerated $4 billion in transportation and infrastructure projects by 1 to 5 years or more. This includes a new rail line, two new freeways, five major freeway-widening projects, a dozen freeway and highway interchange projects, a major dam rehabilitation, a new Metrolink line, major water projects, and major regional power transmission lines.  The Western Riverside County RCA estimates $312 million savings in transportation costs due to early delivery (Based on the National Highway Construction Cost Index Average of 3.9 percent per year and an average time savings).

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-7  Every transportation project proposed in the plan area has been built; none have been stopped or stalled due to ESA or California ESA issues. With the MSHCP in place, ESA compliance no longer impedes the path of project environmental compliance.  Projects with an ESA Section 7 consultation received their biological opinions from U.S. Fish and Wildlife Service in an average of 2 months, versus over 2 years without the MSHCP. 10.3.2 Management and Maintenance Costs and Benefits Mowing the many acres of roadside ROWs every year represents a substantial expenditure, and mowing a limited portion of the ROWs means potential cost savings as well as aesthetic and ecological benefits, without compromising safety. Data is limited, but includes these examples:  Delaware DOT spent over $3.4 million mowing roadsides in 2008. In 2009, budget restrictions forced Delaware DOT to reduce mowing by 25 percent. If Delaware DOT took 500 acres +of roadsides out of routine mowing, the state could save $1.3 million per year (Lucey and Barton 2010).  Florida DOT spent $13 million on roadside mowing in 2011– 2012. The University of Florida, Institute of Food and Agricultural Sciences report, Economic Impact of Ecosystem Services Provided by Ecologically Sustainable Roadside Right of Way Vegetation Management Practices, found that Florida DOT could reduce its costs by 30 percent by implementing sustainable management practices such as reduced mowing (Harrison 2014).  In Florida, Norcini (2014) found that limiting mowing to once a growing season, in the fall, along a stretch of Interstate 10 in Madison County reduced mowing costs by $1,000 per mile. (Typically, that highway is mowed up to seven times a growing season.) A 10- to 15-foot-wide mown strip in the recovery area adjacent to the pavement continued to be mowed seven times each growing season. Over time, more and more desirable plant species were found in the section of the ROW with the reduced mowing regime. As blooming wildflowers increased, the section of the road became more aesthetically appealing, particularly in the spring.  Indiana DOT found a cost savings of over 40 percent can be achieved with one application of herbicide instead of one cycle of mowing, and that there are cost savings associated with planting native vegetation (e.g., prairie plant community wildflowers had a greater initial cost, but that cost was offset in the analysis by lower long-term management costs) (Lucey and Barton 2010).  Mississippi DOT mows approximately 139,253 acres of roadsides four times per year at a cost per acre of greater than $250, or a total annual cost of around $35 million. Reducing mowing of roadsides by one mowing could save approximately $8.7 million; eliminating two mows per growing season could save over $17 million (Guyton et al. 2014). Mowing a highway once a year rather than  seven times allows wildflowers like tall false  foxglove (Agalinis aspera) to flourish in Florida.  Photo Credit: Eleanor Dietrich 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-8 Reduced Mowing, a Triple Bottom Line for DOTs Environmental Benefits  Reduced mowing can allow flowering plants to flower, providing pollinators with pollen and nectar and small wildlife with seeds and fruits. The transition from frequently mowed grass to more diverse grasslands or early successional habitat can increase wildlife habitat quality and reduce habitat fragmentation (AASHTO 2011). More birds use roadside habitat when vegetation is taller and more dense (McCleery et al. 2015) and when mowing does not interrupt grassland breeding season (Warner 1992).  Reduced mowing can mean reduced greenhouse gas emissions from mowing equipment and reduced amounts of carbon stored in plant tissues returned to the atmosphere after mowing. Emissions from mowing can result in up to 35 kilograms (kg) of carbon dioxide (CO2) emissions per shoulder and kilometer (Sonntag et al. 2011). If reduced mowing is implemented in just half of the roadsides associated with the National Highway System, CO2 emissions could be cut by approximately 2 million kg every year (FHWA 2011). Societal Benefits  Non-turf roadside vegetation provides aesthetic variety, breaks up monotony (Billings 1990), and can have a positive effect on human performance and improve driver safety (Topp 1990; Cackowsky and Nasar 2003; Mok et al. 2006; Macdonald et al. 2008).  Public perception surveys have found strong support for more wildflowers on roadsides and reduced mowing, with respondents also indicating they would tolerate a less manicured roadside if it made the roads safer (Guyton et al. 2014). Economic Benefits  Reducing routine mowing of the entire ROW can reduce costs. Other strategies to reduce costs include making only one pass with the mower next to the operational zone rather than mowing the entire ROW multiple times during the growing season.  Though in general reducing routine mowing is a straightforward method of reducing costs for many ROWs, altering the timing of mowing to encourage breeding of imperiled species (e.g., avoiding mowing during peak Karner blue butterfly [Lycaeides melissa samuelis] breeding) or blooming of wildflowers may be less straightforward because there may be other operational constraints to consider (e.g., such as mowing at a time of the year when maintenance staff are trying to prepare for winter). However, if these constraints translate to additional ongoing costs, those costs are likely to be offset by the value of proactive conservation to avert ESA listings.  Mowing can sometimes spread noxious and invasive weeds; switching from routine mowing to more targeted weed control can bring about cost savings.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-9 10.3.3 Revegetation Costs and Benefits: Use of Native Plants Native plants can be used to meet goals for safe and efficient transportation, while supporting ecosystem health. Although the initial costs of establishing native plant material are higher—particularly where a higher density and diversity of flowering plants are required—than the costs of low diversity mixes that are heavy on introduced grasses, native plants are often more cost-effective in the long term. Once established, the plantings persist over time and require less mowing, herbicides, and other weed control measures, decreasing long-term maintenance efforts and cost (Berger 2005). In contrast, controlling the growth and spread of invasive plants along roadsides through repeated mowing and rigorous herbicide use is very expensive (Westbrooks 1998). Another advantage of using a diverse assemblage of native plants in revegetation projects is that it may be more resilient to climate change. For many regions, climate projections include an increase in extreme weather events. Many regions will experience both more frequent drought and more frequent flooding. Having a diverse plant community along roadsides means that the community is more likely to contain plants that will persist under different conditions and will continue to provide benefits like erosion control. Though data is limited, what does exist indicates that establishing native vegetation on roadsides can reduce maintenance costs. Consider these examples:  Texas DOT estimated an annual mowing cost savings of $20–$30 million through wildflower establishment (Guyton et al. 2014).  In 1987, Massachusetts Department of Public Works managed roadsides at a cost of about $1.1 million, or $330 per acre; if every acre was instead managed as wildflowers, nearly $280 per acre per year could be saved (Ahern et al. 1992).  In California’s Yolo County, Robins et al. (2001) estimated roadside native vegetation installation costs, which included earthwork, tillage, herbicide, and seeding, at $522 to $1,433 per acre of roadside. They estimated maintenance costs for each of the first 3 years of establishment at $52 to $153 per acre, with similar maintenance costs occurring subsequently every 2 to 3 years. Standard roadside management, for comparison, costs $140 to $490 per acre per year. Reducing Costs and Finding Funding to Support the Use of Native Plant Materials Obstacles encountered by transportation agencies seeking native plant materials can include the cost and, depending on region, the availability of locally or even regionally sourced native plant materials. Some solutions that transportation agencies have used to fund plant material purchases or increase the supply of native plant material include the following:  Committing to purchasing and planting seed or plant material that originates in the state or region. Coordinate with local or regional native plant vendors about plant material needs for projects 3–5 years in the future, so the vendors can plan ahead to have the plant material available. Such a sustained commitment fosters a stable market that will lead to greater production and reduced costs.  Partnering with private nurseries or state agencies in a cooperative effort to build up a local plant material industry.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-10  Taking advantage of federal funding. Planting native vegetation is an eligible use of federal-aid highway funds. The cost of native plant materials purchased for revegetation projects can be reimbursed by the FHWA.  Finding alternative sources of funding to support the planting of roadside wildflowers. For example, a state might offer a specialty wildflower license plate, the sales of which support the purchase and installation of wildflowers on roadsides, or the state transportation agency could partner with a state or local organization that obtains funding from the FHWA’s Surface Transportation Block Grant Program to implement vegetation restoration. Native Plants in New Roadside Plantings, a Triple Bottom Line Win! In addition to their value to pollinators, there are many advantages of using native plants to providing triple bottom line benefits: Environmental Benefits  Native grasses and flowers are best adapted to local growing conditions, require minimal inputs for establishment, and are better able to tolerate extreme weather events such as drought.  Native plant communities also support more birds, pollinators, and other wildlife.  The use of native plants in roadsides can provide ecological benefits to the surrounding landscape. Societal Benefits  Native plants can be aesthetically pleasing during the growing season.  Native plants can act as snow fences in the winter, trapping and preventing snow from blowing across roads.  The root systems of native plants can increase water infiltration, which reduces runoff and water pollution and keeps waters cleaner. Economic Benefits  Although native plants may cost more upfront, they can provide cost savings over time.  A diverse native plant community can reduce soil erosion and resist weed invasions, which can reduce maintenance costs.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-11 Case Study: Prairie Plants More Cost-Effective over Time on Indiana Roadsides A collaborative highway research project involving researchers from Purdue University, the Indiana DOT, and the FHWA evaluated plants for use on Indiana’s roadsides. Specifically, the project looked at establishment of three types of roadside plantings: turfgrass, garden wildflower mixes, and native wildflower mixes. The project team also calculated costs of establishment and maintenance of each approach (Dana et al. 1996). Turf plantings were a mix of introduced grasses installed as sod, while the garden wildflower seed mix included 11 species of short-lived annuals or biennials, primarily introduced species such as cosmos, California poppy, and rocket larkspur. The native prairie seed mix was 8 species—3 native grass species (20 percent of the mix) and 5 wildflower species (80 percent of the mix). Garden wildflowers were the least costly to establish, but maintenance was more costly over time, including reseeding repeatedly over time due to the short lifespan of the plants. Another downside of the garden wildflowers mix is that it was not appropriate for erosion control. The prairie plant mixes were more costly up front, but researchers found that the more permanent turfgrass and prairie plantings were cost competitive when long- term management costs were incorporated. This study, conducted in the mid-1990s, reflects the higher costs of native seed at the time. Native seed mixes are more affordable and available today, so the mix tested in this study would cost much less if purchased today. For example, a significantly more diverse native seed mix of 22 species could be purchased from a local Indiana native plant nursery in 2021 for about $400 per acre. That is considerably less than the $2,179.44 cost per acre for the mix included by Dana et al. in 1996. An updated analysis of the costs associated with revegetation of roadsides and roadside vegetation management would be highly beneficial. 10.4 Incorporating Costs and Benefits  into the Planning and Design Phases   During the planning and design process, it is important to consider actions to benefit pollinators early and often (such as revegetation or location considerations) so that they can be included in the project and costs can be incorporated into the project budget. Weighing the short-term vs. long-term costs and benefits of pollinator conservation actions and using the triple bottom line approach outlined below may aid in this process. 10.4.1 Short-Term vs. Long-Term Costs and Benefits Humans are notoriously bad at making long-term decisions (Ornstein and Ehrlich 1989). People have evolved to make decisions based on perceived risk (cost) and expected reward (benefit), and their brains are much better equipped to judge and react to near-term risks and rewards. However, to make better decisions people need to consider the full implications of the Native plants develop extensive root systems  over time that are important for erosion control,  water infiltration, weed resistance, carbon  sequestration, and more.  Photo Credit: Kirk Henderson 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-12 decision over time. This is especially true when considering decisions regarding sustainability and the triple bottom line (Waite 2013). When planning transportation projects, it is relatively easy to add up the short-term costs of planning, design, and construction, and relatively easy to understand conceptually long- term economic and societal gains of transportation system improvements. But when considering project elements to benefit pollinators (or any environmental resource) it is easy to be dissuaded by short-term costs if the long-term environmental and additional associated societal benefits are not carefully described and considered, or if the potential long-term cost savings are not considered. Most pollinator-friendly project elements include actions to change the species composition and distribution of the plant community. Plants take time to grow and become established, and the pollinator community will take time to discover and then disperse into the newly improved habitat conditions. Revegetation and habitat management projects typically require a larger initial investment of time and money until they become established and self-sustaining due to more intensive watering, weeding, and management needs, which are not required once the plants are established, leading to reduced long-term costs. Once the desired pollinator habitat is established a range of benefits that diverse habitat confers will start to emerge, such as ameliorating climate change through increased carbon sequestration, reduced soil erosion, increased water infiltration, and, in agricultural settings, crop pest control and crop pollination. These environmental and societal benefits increase over time; therefore, it is important to establish the proper time frame for analysis in a triple bottom line cost-benefit analysis. Table 10-1. Examples of the benefits of DOT pollinator conservation that could be considered when using the triple bottom line framework to evaluate the costs and benefits of conservation actions. Environmental Benefits  Societal Benefits  Economic Benefits   Supports local  pollinator communities   Supports imperiled  pollinators   Supports other wildlife   Diverse plantings are  more likely to be  resilient to climate  change   Controls erosion    Reduces runoff;  reduces flood risk    Suppresses weeds    Reduces mowing  frequency, which  reduces greenhouse  gas emissions   Protects pollinators  and imperiled species   Roadside habitat  preserves natural  heritage   Pollinator habitat is  aesthetically pleasing  and showcases  regional beauty   Pollinator habitat  increases interest for  drivers and can  improve driver safety  Increases carbon  sequestration in  roadsides through  diverse plantings   Potential for increased  pollination services to  surrounding landscape   Potential for increased pest  predation services to  surrounding landscape   Weed suppression, which can  reduce long‐term  maintenance costs   Reduced mowing frequency,  which reduces mowing costs   Reduced risk of new species  being listed under the ESA,  which reduces costs and  project delays   Increased tourism due to  scenic roads   Improved plant infrastructure,  which can protect roads 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-13 10.4.2 Triple Bottom Line Cost-Benefit Analysis Tool The purpose of this tool is to assist state DOTs in evaluating design features and maintenance actions that can be implemented to benefit pollinators. This tool will assist with organizing cost and benefit information, establishing the environmental and temporal contexts for evaluation, and providing the rationale and justification for selection of the preferred choice, considering the short- and long-term environmental, societal, and economic costs and benefits. As discussed previously, it is challenging to quantify the range of costs and benefits across all elements of the triple bottom line. Therefore, costs and benefits are evaluated qualitatively as a relative change compared to the status quo (e.g., costs are higher, the same, or lower to implement an action compared to current costs). Qualitative cost differences need to be evaluated relative to the overall project costs. For example, including native seed in a new interchange construction project may seem expensive because native seed costs more than nonnative seed. However, relative to the overall cost of the interchange construction, proportionally this is a very small additional cost. Therefore, this would be considered a low relative cost overall. In contrast, switching to native seed for interseeding (also known as overseeding) an existing ROW during ongoing operations and maintenance is proportionally a larger additional cost that would be considered a medium or higher relative cost as ROW maintenance is a much smaller total cost than new construction. The temporal context is important to consider as well. In the previous example the more expensive native seed may be a proportionally larger short-term cost, but if the long-term maintenance for native species is lower, then the investment in native seed leads to long-term savings. Finally, under the sustainability-centered framing of the triple bottom line model, in many cases the total long-term benefits to society and the environment can justify higher economic costs of actions that benefit pollinators compared to the status quo (which does not support a robust pollinator community). Use of this tool will help state DOTs develop pollinator-friendly practices and will them present the rationale for selected actions to decision-makers. This tool is available as a Word document on the National Academies Press website, https://nap.nationalacademies.org/. Steps to Conduct a Triple Bottom Line Cost-Benefit Analysis for Pollinators on Roadsides There are three basic steps to using this tool to evaluate pollinator-friendly measures for roadsides: define, evaluate, and decide. The process to implement each of these steps is described below. Prompts have been provided to help the user conduct a more complete analysis. 1. Define: Describe the project area where the action is to be implemented. a. Describe the landscape context for the project area, including adjacent land uses and distances between natural habitats where roadsides traverse urbanized or agricultural landscapes. b. Describe in detail the pollinator-friendly action or project element being considered.

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-14 c. Describe the intended outcome of the action using the pollinator cost-benefit cubes (refer to the Pollinator Cost-Benefit Cubes section below) to determine the potential benefits to the pollinator community in general, and to imperiled pollinators in the project area. d. Define and then describe the appropriate time frames for analysis (short-term project implementation and long-term operations to realize fulfillment of project results). 2. Evaluate: Consider the costs and benefits from an environmental, societal, and economic perspective. a. Environmental Evaluation: List all the potential environmental benefits (including pollinator benefits) that might result from the action and rate the likely strength of the benefit as high, medium, or low. Use the prompt questions to contribute to the evaluation. b. Societal Evaluation: List all the potential societal benefits that might result from the action and rate the likely strength of the benefit as high, medium, or low. Use the prompt questions to contribute to the evaluation. c. Economic Evaluation: Adjust the relative cost in the pollinator cost-benefit cube as needed for the region and landscape context. Consider how total costs change over time, from short-term initial investment costs to potential long-term cost savings. Rate the likely strength of the economic costs and benefits as high, medium, or low. Use the prompt questions to contribute to the evaluation. 3. Decide: Place the evaluation results in three columns (Environmental, Societal, and Economic) in descending order of rating (high, moderate, low). With the importance of long-term sustainability in mind, review the triple bottom line costs and benefits side by side and decide if the complete suite of benefits justify the potential costs. Describe the rationale for the decision. Prompts for DOT Staff to Apply Cost-Benefit Matrix to Their Pollinator Management Decisions Environmental Evaluation Prompts  Could the action provide medium to high benefits to native pollinators?  Could the action provide benefits to listed pollinators (state or federally regulated species)?  Is the action adjacent to or near agricultural lands where it could support beneficial crop pollination services?  Does the action have ecological benefits that extend beyond those to pollinators (e.g., does it increase habitat for birds or improve water infiltration)? Societal Evaluation Prompts  Does this action increase the aesthetics of the area where work is being done?

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-15  Is the project located on a stretch of road in which the landscape is monotonous, and increasing plant diversity could improve driver safety?  Does the action have landscape benefits that extend beyond benefits to pollinators (e.g., does it increase carbon sequestration)?  Is the general public engaged and interested in pollinator conservation, and will it respond supportively to actions the DOT may take?  Is the project good for public relations for the agency? Economic Evaluation Prompts  Does the action cost more or less in the short term than current practices?  Does the action cost more or less in the long term than current practices?  Are costs higher in the short term but the benefits are more long lasting?  Would the cost to implement this action prevent implementation of other essential operations?  Does the action help contribute to an agreement that provides compliance and regulatory assurances (e.g., a Candidate Conservation Agreement with Assurances)? Example: Application of Triple Bottom Line Cost-Benefit Tool This sample application of the cost-benefit tool uses the proposed pollinator-friendly management action “Limit mowing beyond the mown strip in the recovery area to once or less per year.” Cost-benefit cubes for other conservation actions are included in the Pollinator Cost-Benefit Cubes section below. Sample Pollinator Cost-Benefit Cube Mowing  Limit mowing beyond the clear zone to no more  than twice per year.  Benefit  High  Medium  Low  Co st   Low  I, G  Medium  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-16 Pollinator Cost-Benefit Cubes Use these cubes to identify conservation actions for pollinators to consider in roadside projects and management. Integrate the selected cubes into the triple bottom line cost- benefit analysis as described in the Steps to Conduct a Triple Bottom Line Cost-Benefit Analysis for Pollinators on Roadsides section above. The actions are grouped into five different categories: mowing, herbicides, mechanical weed and brush removal, revegetation, and training/education. Table 10-2 lists the benefits to imperiled pollinators and the general pollinator community that are associated with conservation actions that might be implemented on roadsides. The benefits of each action are indicated across the top of the cube as High, Medium, or Low for the general pollinator community (indicated with a G) and imperiled pollinator species (indicated with an I). Similarly, relative cost to implement the action is indicated along the side as Low, Medium, or High. Costs are based on general assumptions for standard implementation of these actions. However, costs may vary by region, and the costs may be adjusted up or down to indicate expected relative costs for the action being considered in the specific project area. Mowing Mowing Mowing  Avoid mowing imperiled butterfly host plants  during butterfly breeding seasons.  Adjust mowing height to a minimum height of 8  to 10 inches in areas with target butterfly host  plants or bumble bee colonies in grass thatch if  mowing during the growing season.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  I  G  Co st   Low  I  G  Medium  I  G  Medium  High  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-17 Mowing Mowing  Limit mowing beyond the clear zone to no more  than twice per year.  Aim to mow no more than one‐third to half of an  area beyond the clear zone per year (e.g., rotate  mowing sections of a roadside).  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  G  I, G  Co st   Low  I, G  Medium  Medium  High  High  I= Benefits to imperiled species; G= Benefits to general pollinator community  Mowing Mowing  Limit mowing beyond the clear zone to once or  less per year.  Clean mowing equipment after use and between  sites to limit the spread of weeds.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  I, G  Co st   Low  I, G  Medium  Medium  High  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-18 Mowing  Delay mowing as late as possible during the  growing season (e.g., mow in autumn) so  blooming plants are available throughout the  growing season.       Benefit         High  Medium  Low     Co st   Low           Medium  I, G  I, G       High                      I= Benefits to imperiled species; G= Benefits to general pollinator community  Herbicides Herbicides    Herbicides  Avoid use of products that have toxicity to  imperiled Lepidopteran species during breeding  seasons.    Train staff and contractors to recognize native  plants and noxious and invasive weeds to reduce  unintended damage to nontarget plants.        Benefit          Benefit         High  Medium  Low            High  Medium  Low    Co st   Low              Co st   Low          Medium  I, G  G          Medium  I, G        High  I, G  G        High                                    I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-19 Herbicides Herbicides  Direct herbicide applications to undesirable  plants to avoid harming nontarget species (e.g.,  spot‐treatment applications with a backpack  sprayer, targeted applications to cut stems).  Avoid herbicide sprays when weather conditions  increase drift (e.g., avoid wind speeds >15 mph;  avoid applications during a temperature  inversion).  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  Co st   Low  Medium  I, G  Medium  I, G  High  I, G  High  I= Benefits to imperiled species; G= Benefits to general pollinator community  Herbicides Herbicides  Choose and operate equipment with drift  management in mind (e.g., calibrate equipment  regularly; choose spray nozzles to reduce drift;  on boom sprayers; use the lowest effective  pressure and largest droplet size possible).  Avoid broadcast applications of systemic  herbicides and herbicides with long residuals to  reduce exposure to butterfly and moth  caterpillars that can be exposed to residuals by  consuming contaminated vegetation.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  I, G  I, G  Co st   Low  Medium  Medium  I, G   G  High  High  I, G  G  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-20 Herbicides    Herbicides  If necessary (e.g., if the seed bank was depleted  of desirable species), replant areas that have  been treated with herbicides to remove dense  infestations of undesirable vegetation with  desirable, competitive, low‐growing plant species  to reduce the need to re‐treat the area.    When feasible, hand pull or use another  mechanical control strategy if in an area where  herbicide use might result in impacts on  imperiled species.       Benefit          Benefit         High  Medium  Low            High  Medium  Low    Co st   Low              Co st   Low          Medium    I, G          Medium          High            High  I  G                                I= Benefits to imperiled species; G= Benefits to general pollinator community    Herbicides    Herbicides  Use selective herbicides whenever possible to  reduce damage to nontarget plants.    Apply herbicides during plant life stages when  weeds are most vulnerable (e.g., before blooming  or before going to seed).       Benefit          Benefit         High  Medium  Low            High  Medium  Low    Co st   Low              Co st   Low          Medium  I, G            Medium  I, G  I, G      High            High  I, G  I, G                                I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-21 Herbicides Herbicides  Whenever possible, prevent conditions that  would allow incompatible vegetation or noxious  and invasive species to establish or reestablish.  Train staff and contractors to recognize and avoid  applications to key host plants for target  imperiled butterflies and moths or key nectar  plants for bumble bees.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  Co st   Low  Medium  I, G  G  Medium  I  G  High  High  I= Benefits to imperiled species; G= Benefits to general pollinator community  Mechanical Weed and Brush Removal Mechanical Weed and Brush Removal Mechanical Weed and Brush Removal  Minimize soil disturbance (disking, tilling) during  brush removal activities to avoid spreading  invasive plants and destroying overwintering  sites or nests.  Time activities to avoid vulnerable times for focal  species.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  I, G  Co st   Low  Medium  Medium  High  High  I  G  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-22 Mechanical Weed and Brush Removal Mechanical Weed and Brush Removal  Feather or soften forest edges adjacent to clear  zones to create a transitional area between the  forest and grass (e.g., thin portions of the forest  canopy along the edge next to grassy areas,  removing undesirable or unhealthy trees).  Leave snags or trees with cavities in areas where  they are set back from the road and pose no  safety risk.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  Co st   Low  I, G  Medium  I, G  Medium  High  High  I= Benefits to imperiled species; G= Benefits to general pollinator community  Revegetation Revegetation Revegetation  Increase flowering plant diversity in all plantings.    Prioritize native plants in all plantings   (revegetated and landscape).  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  Co st   Low  Medium  Medium  I, G  High  I, G  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-23 Revegetation Revegetation  Increase host plants in revegetation plantings. Interseed host plants into existing roadside  vegetation.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  I, G  Co st   Low  Medium  I, G  Medium  I, G  G  High  I  G  High  I, G  G   I= Benefits to imperiled species; G= Benefits to general pollinator community  Revegetation Revegetation  When possible, salvage native plants at  construction site for replanting.  Control weeds to reduce weed competition and  allow native seedlings to grow in the first and  second years after planting. Prevent weeds from  going to seed.  Benefit Benefit High  Medium  Low  High  Medium  Low  Co st   Low  Co st   Low  I, G  Medium  Medium  I, G  High  I  G  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-24 Training/Education Training/Education  Provide training for staff for education about why  the transportation agency takes conservation  actions for pollinators.  Benefit High  Medium  Low  Co st   Low  I, G  I, G  Medium  I, G  I, G  High  I= Benefits to imperiled species; G= Benefits to general pollinator community 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-25 Table 10-2. Value of benefits to pollinators of potential conservation actions to be implemented by DOTs. Conservation actions  Benefits to  general  pollinator  community  Benefits to  imperiled  species  Mowing  Avoid mowing imperiled butterfly host plants during butterfly  breeding seasons  Medium  High  Adjust mowing height to a minimum height of 8–10 inches in  areas with target butterfly host plants or bumble bee colonies  in grass thatch if mowing during the growing season  Medium  High  Limit mowing beyond the mown strip in the recovery area to  once or less per year  High  High  Aim to mow no more than 1/3–1/2 of an area beyond  the mown strip in the recovery area per year (e.g., rotate  mowing sections of a roadside)  High  High  Limit mowing beyond the mown strip in the recovery area to  no more than twice per year  Medium/High  Medium  Delay mowing as late as possible during the growing season  (e.g., mow in autumn), so blooming plants are available  throughout the growing season  Medium/High  Medium/High  Clean mowing equipment after use and between sites to limit  the spread of invasive weeds  Medium  Medium  Herbicide Use  Train staff and contractors to recognize and avoid applications  to key host plants for target imperiled butterflies and moths or  key nectar plants for bumble bees  Medium  High  Avoid use of products that have toxicity to imperiled butterfly  and moth species during breeding seasons  Medium/High  High  Hand pull or use another mechanical control strategy if in an  area where herbicide use might impact imperiled species,  when feasible  Medium  High  Train staff and contractors to recognize native plants as well as  noxious and invasive weeds to reduce unintended damage to  nontarget plants  High  High  Use selective herbicides whenever possible to reduce damage  to nontarget plants  High  High 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-26 Conservation actions  Benefits to  general  pollinator  community  Benefits to  imperiled  species  Direct herbicide applications to undesirable plants to avoid  harming nontarget species (e.g., spot treatment applications  with a backpack sprayer, targeted applications to cut stems,  etc.)  High  High  Apply herbicides during plant life stages when weeds are most  vulnerable (e.g., before blooming or before going to seed)  Low/Medium  Low/Medium  Avoid herbicide sprays when weather conditions increase drift  (e.g., avoid wind speeds >15 miles per hour, avoid applications  during a temperature inversion)  High  High  Choose and operate equipment with drift management in  mind (e.g., choose spray nozzles to reduce drift; on boom  sprayers, use the lowest effective pressure and largest droplet  size possible)  Low/Medium  Low/Medium  Avoid broadcast applications of systemic herbicides and  herbicides with long residuals, thus reducing exposure to  butterfly and moth caterpillars that can be exposed to  residuals by consuming contaminated vegetation  Medium/High  High  Whenever possible, prevent conditions that would allow  incompatible vegetation or noxious and invasive species to  establish or reestablish  Medium/High  High  If necessary (e.g., if the seed bank was depleted of desirable  species), replant areas that have been treated with herbicides  to remove dense infestations of undesirable vegetation with  desirable, competitive, low‐growing plant species to reduce  the need to re‐treat the area  Medium  Medium  Mechanical Weed and Brush Removal  Time activities to avoid vulnerable times of focal species  Medium  High  Feather or soften forest edges adjacent to the mown strip in  the recovery area to create a transitional area between the  forest and grass (e.g., thin portions of the forest canopy along  the edge next to grassy areas, removing undesirable or  unhealthy trees)  Medium  Medium  Leave snags or trees with cavities in areas where they are set  back from the road and pose no safety risk  Medium  Medium  Minimize soil disturbance (disking, tilling) during brush  removal activities to avoid spreading invasive plants and  destroying overwintering sites or nests  Medium  Medium 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-27 Conservation actions  Benefits to  general  pollinator  community  Benefits to  imperiled  species  Revegetation  Prioritize native plants in all plantings (revegetation and urban  landscaping)  High  High  Increase flowering plant diversity in all plantings  High  High  Increase host plants in revegetation plantings  High  High  Control weeds to reduce competition while allowing native  seedlings to grow—this is critical in the first and second years  after planting—and weeds should also be prevented from  going to seed  High  High  Interseed host plants into existing roadside vegetation  Medium/High  High  Weed control prior to planting  High  High  When possible, salvage native plants at the construction site  for replanting  Medium  High  Training/Education  Provide training for staff for education about why  conservation actions are taken by the transportation agency  for pollinators  Medium/High  Medium/High 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-28 Worksheet for Triple Bottom Line Cost-Benefit Tool De fin e  Describe the project area  Describe the landscape context  Describe the intended outcome  Define and describe the timeframe for analysis 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-29 Ev al ua te   Strength of Factor  Environmental  High  Medium  Low  Societal  High  Medium  Low  Economic  High  Medium  Low 

Chapter 10. Cost‐Benefit Considerations for Pollinator Management on Roadsides  10-30 De cid e  Rationale for Decision:  List in order of strength of factors  Hi gh   Environmental  Societal  Economic  M ed iu m   Lo w  

Next: Chapter 11: Communication Support »
Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin Get This Book
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 Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin
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Transportation agencies can make a difference for imperiled pollinators by managing existing roadside vegetation and designing new revegetation plantings with habitat needs in mind. This can generate public support for the agency and help to mitigate the negative ecological effects of roads.

NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 4: Great Basin, from TRB's National Cooperative Highway Research Program, is part of a 16-volume series, with each volume focused on a specific region of the United States, and is intended to provide relevant guidance to rights-of-way owners and operators for roadside vegetation management practices that support pollinators, as well as strategies that are compliant with the federal Endangered Species Act.

Supplemental to the document are a Dataset of Great Basin Accessory Materials, a Communications Toolbox, a Conduct of Research Report, and a Video.

All the other volumes are available on the webpage for NCHRP Web-Only Document 362: Pollinator Habitat Conservation Along Roadways, Volume 1: Alaska.

The other volumes are:

Volume 1: Alaska

Volume 2: California

Volume 3: Florida

Volume 5: Great Lakes

Volume 6: Hawaii

Volume 7: Inland Northwest

Volume 8: Maritime Northwest

Volume 9: Mid-Atlantic

Volume 10: Midwest

Volume 11: Northeast

Volume 12: Northern Plains

Volume 13: Rocky Mountains

Volume 14: Southeast

Volume 15: Southern Plains

Volume 16: Southwest

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