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1-1 Chapter 1 Introduction Animal pollinators are central to human wellbeing, agricultural production, global economic health, and the viability of native plant communities and wildlife. Thirty-five percent of global crop production is dependent on pollinators, including 87 of the worldâs 124 most commonly cultivated crops (Klein et al. 2007). Also, many minerals, vitamins, and nutrients needed to maintain human health come from insect-pollinated crops (Eilers et al. 2011). Pollinators are essential for the reproduction of about 85 percent of all flowering plants (Ollerton et al. 2011) and are critical for wildlife food webs (Kearns et al. 1998; Summerville and Crist 2002). Insects, including bees, wasps, flies, beetles, butterflies, and moths, are the primary pollinators in much of North America (Allen-Wardell et al. 1998; Kearns 2001), yet a number of insect pollinators are in decline. Pollinators that have undergone troubling and dramatic declines over the past few decades include rare species with narrow habitat needs, as well as formerly common and widespread species like the rusty patched bumble bee (Bombus affinis) and the monarch butterfly (Danaus plexippus) (Hatfield et al. 2016; Semmens et al. 2016; Schultz et al. 2017). Factors leading to pollinator decline include habitat loss, pesticide use, diseases, parasites, climate change, and the spread of invasive species. 1.1 WhyÂ RoadsidesÂ AreÂ ImportantÂ toÂ PollinatorsÂ Threats to pollinators may have profound consequences for ecosystem health as well as our food systems (Kearns et al. 1998; Spira 2001; Steffan-Dewenter and Westphal 2008). Roadsides can help mitigate habitat loss for pollinators. State departments of transportation (DOTs) manage substantial amounts of land and associated natural resources across North America, including upward of 10 million acres of roadside land in the United States (Forman et al. 2003). These acres hold the potential to create a network of habitats to support pollinators in urban and rural areas. Roadsides can provide habitat for all life stages of a diverse community of pollinators (Hopwood et al. 2015), including imperiled pollinators. Roadsides may also act as corridors for pollinators (see review in Hopwood et al. 2015), connecting remnant habitat patches and aiding pollinators to move through landscapes or expand their ranges. Mining beesâsuch as this bee visiting an apple blossomâand other wild pollinators are critical for food production. Photo Credit: Nancy Lee Adamson/Xerces Society
ChapterÂ 1.Â IntroductionÂ 1-2 In some places, roadsides are home to intact native plant communities that are no longer found in surrounding lands (New et al. 2021). Searching for prairie remnants in some parts of the Corn Belt in the Midwest, for example, often requires scouring roadsides and railroad rights-of-way. In heavily altered landscapes, even those roadsides without intact native plant communities can be the only semi-natural habitat present (e.g., Brown and Sawyer 2012). For some listed or imperiled species of pollinators, roadsides include some of the last remaining patches of their habitat. Widespread species that are struggling, such as the monarch butterfly or the rusty patched bumble bee, are not completely reliant on roadsides habitat, but roadsides are still an important component of their survival (e.g., Thogmartin et al. 2017; Evans et al. 2019). A number of state DOTs have an interest in managing roadsides to support pollinators (e.g., Hopwood et al. 2016b; National Cooperative Highway Research Program Project 25-59 Conduct of Research Report), but as more species of pollinators become listed or are being considered for listing under the Endangered Species Act (ESA), DOTs also want regulatory certainty. Currently (March 2022), there are 48 pollinating insects listed under the federal ESA (nine bees, 35 butterflies, two moths, one fly, and one beetle). This includes two species that are either a candidate species or proposed for listing, and many more species with declining populations and the potential to be listed. Figure 1- 1 shows the number of species that are currently listed or a candidate for listing by region. Figure 1-1. Map of the United States, with the number of pollinator species that are currently listed or candidates for listing under the Endangered Species Act (as of March 2022) within each of the 16 regions covered in these guides. ï· Alaska:Â 0 ï· MaritimeÂ Northwest:Â 5 ï· InlandÂ Northwest:Â 1 ï· Hawaii:Â 8 ï· California:Â 2 ï· GreatÂ Basin:Â 2Â ï· Southwest:Â 2 ï· RockyÂ Mountains:Â 3 ï· NorthernÂ Plains:Â 4 ï· SouthernÂ Plains:Â 1 ï· Midwest:Â 4 ï· GreatÂ Lakes:Â 5Â ï· Southeast:Â 3Â ï· Florida:Â 8 ï· MidâAtlantic:Â 4 ï· Northeast:Â 3 Roadsides provide monarch butterflies with food for adults as well as caterpillars. Photo Credit: John Anderson 0 5 1 2 2 2 1 43 4 5 3 8 4 3 8 GUIDE REGIONS
ChapterÂ 1.Â IntroductionÂ 1-3 In addition to supporting pollinators, other benefits of healthy roadside vegetation include a safe driving environment, reduced soil erosion, enhanced rainwater infiltration, improved water quality, reduced wind velocity, carbon sequestration, and habitat for a variety of wildlife, including predator and parasitoid insects that reduce crop pests. 1.2 AboutÂ ThisÂ GuideÂ This guide 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 ESA. This guide will help DOTs and other entities that manage roadsides understand pollinators generally and imperiled pollinators specifically, and it provides information on how to manage roadsides with the goal of avoiding further declines of these important species, averting the need for them to be listed under the ESA in the future. This guide will also help DOTs make informed management decisions to coordinate ESA compliance with their operations, reduce future regulatory uncertainty, contribute to pollinator conservation and recovery, and increase awareness and the associated societal values for the ecosystem services pollinators provide for agriculture and native ecosystems alike. This guide is one of 16 guides, one for each region identified based on ecoregions and distributions of pollinators (Figure 1-1). Each guide includes general information applicable across all 50 states as well as region-specific information developed for the habitats and pollinator species expected to occur in and adjacent to roadways of this region. The intended users of this guide are staff from transportation planning, design, construction, maintenance, and environmental disciplines, as well as communication staff. This guide was informed by review of scientific literature, research reports, and other relevant information, including input from transportation agency practitioners and researchers with expertise on imperiled pollinator species or roadside restoration. This input was obtained through detailed online surveys sent to leading pollinator and roadside revegetation researchers from across the United States and to DOT staff from around the country. Experts were asked to identify the relative benefit of specific conservation actions for imperiled pollinators and provide input on the opportunities for DOTs to implement practices that support pollinators. Participants included researchers from universities, state agencies, consultants, and non-governmental organizations. DOT staff were asked about current practices and potential barriers to implementing additional conservation measures. In total, 70 transportation professionals from DOTs representing agencies from 33 states responded, with 47 percent of respondents self-identifying their expertise within their agency as âEnvironmental,â 27 percent as âMaintenance,â 13 percent as âLandscape Architecture,â 3 percent as âConstruction,â 1 percent as âPlanning,â and 9 percent as âOther.â ListedÂ species:Â AÂ speciesÂ listedÂ asÂ endangeredÂ orÂ threatenedÂ underÂ theÂ federalÂ ESA;Â theÂ speciesÂ hasÂ beenÂ determinedÂ toÂ beÂ inÂ dangerÂ ofÂ extinctionÂ inÂ theÂ nearÂ orÂ foreseeableÂ futureÂ byÂ theÂ U.S.Â FishÂ andÂ WildlifeÂ Service.Â Â CandidateÂ species:Â AÂ speciesÂ thatÂ hasÂ beenÂ foundÂ warrantedÂ forÂ listingÂ underÂ theÂ ESA,Â butÂ whoseÂ listingÂ isÂ precludedÂ byÂ higherâpriorityÂ species.Â ProposedÂ species:Â AÂ speciesÂ thatÂ hasÂ beenÂ proposedÂ forÂ listingÂ asÂ threatenedÂ orÂ endangeredÂ underÂ theÂ ESA.Â PetitionedÂ species:Â AÂ speciesÂ forÂ whichÂ aÂ petitionÂ toÂ listÂ theÂ speciesÂ underÂ theÂ ESAÂ hasÂ beenÂ receivedÂ andÂ isÂ beingÂ evaluated.Â ImperiledÂ species:Â AÂ speciesÂ thatÂ isÂ inÂ declineÂ andÂ mayÂ beÂ inÂ dangerÂ ofÂ extinction.Â ThisÂ termÂ includesÂ speciesÂ thatÂ areÂ notÂ legallyÂ protectedÂ underÂ theÂ ESA.Â
ChapterÂ 1.Â IntroductionÂ 1-4 This guide includes eleven chapters, some of which have specific audiences and others that may be more broadly of use to transportation officials. Table 1-1 provides an overview of this guide and how it can be used. Table 1-1. Using this guide. ChapterÂ ContentsÂ ChapterÂ 2,Â PollinatorÂ BiologyÂ andÂ RoadsidesÂ ThisÂ chapterÂ includesÂ backgroundÂ informationÂ onÂ pollinatorÂ biology,Â including:Â Â ï· aÂ primerÂ onÂ pollinatorsÂ andÂ theirÂ habitatÂ needs, ï· pollinatorÂ conservationÂ status,Â and ï· howÂ pollinatorsÂ useÂ roadsides. ChapterÂ 3,Â ImperiledÂ PollinatorÂ ProfilesÂ ThisÂ chapterÂ includesÂ profilesÂ ofÂ listed,Â candidate,Â andÂ imperiledÂ pollinatorsÂ inÂ thisÂ region.Â TheÂ profilesÂ contain:Â Â ï· lifeÂ historyÂ information, ï· theÂ currentÂ rangeÂ ofÂ distributionÂ withinÂ theÂ region, ï· flightÂ timesÂ forÂ adults, ï· larvalÂ activityÂ forÂ managementÂ timingÂ forÂ butterflies andÂ moths, ï· importantÂ plants,Â and ï· guidanceÂ toÂ helpÂ integrateÂ aÂ speciesâÂ biologyÂ into managementÂ plans. ChapterÂ 4,Â NativeÂ PollinatorsÂ andÂ theÂ FederalÂ EndangeredÂ SpeciesÂ Act:Â ComplianceÂ StrategiesÂ forÂ StateÂ DepartmentsÂ ofÂ TransportationÂ ThisÂ chapterÂ provides:Â Â ï· backgroundÂ onÂ theÂ ESAÂ and ï· informationÂ aboutÂ strategiesÂ forÂ complianceÂ asÂ it relatesÂ toÂ imperiledÂ pollinators. ChapterÂ 5,Â ConsideringÂ ImperiledÂ PollinatorsÂ inÂ TransportationÂ Planning,Â Design,Â andÂ ConstructionÂ ThisÂ chapterÂ discussesÂ whenÂ andÂ howÂ pollinatorsÂ needÂ toÂ beÂ consideredÂ inÂ theÂ transportationÂ planning,Â design,Â andÂ constructionÂ phasesÂ ofÂ projectÂ delivery.Â ItÂ identifies:Â Â ï· opportunitiesÂ toÂ includeÂ pollinatorâfriendlyÂ design elementsÂ and ï· howÂ projectÂ designÂ andÂ constructionÂ canÂ incorporate measuresÂ toÂ avoidÂ andÂ minimizeÂ potentialÂ impactsÂ on pollinators.
ChapterÂ 1.Â IntroductionÂ 1-5 ChapterÂ ContentsÂ ChapterÂ 6,Â RoadsideÂ MaintenanceÂ andÂ VegetationÂ ManagementÂ forÂ PollinatorsÂ ThisÂ chapterâsÂ audienceÂ isÂ maintenanceÂ staff,Â planners,Â orÂ thoseÂ designingÂ revegetationÂ plans.Â ThisÂ chapterÂ provides:Â Â ï· anÂ overviewÂ ofÂ howÂ vegetationÂ managementÂ practices affectÂ pollinatorsÂ and ï· regionâspecificÂ adjustmentsÂ ofÂ practicesÂ toÂ better supportÂ imperiledÂ pollinators. ChapterÂ 7,Â RevegetationÂ andÂ Pollinators:Â DesignÂ andÂ ImplementationÂ ThisÂ chapterÂ includes:Â Â ï· aÂ guideÂ onÂ howÂ toÂ supportÂ imperiledÂ pollinators throughÂ revegetationÂ and ï· detailedÂ regionalÂ plantÂ speciesÂ lists. ChapterÂ 8,Â CreatingÂ Climateâ SmartÂ PollinatorÂ HabitatÂ alongÂ RoadsidesÂ ThisÂ chapterÂ exploresÂ waysÂ toÂ increaseÂ climateÂ resiliencyÂ forÂ pollinators.Â ChapterÂ 9,Â Surveys,Â MonitoringÂ Strategies,Â andÂ HabitatÂ AssessmentsÂ SurveysÂ canÂ determineÂ theÂ presenceÂ ofÂ imperiledÂ species,Â andÂ monitoringÂ canÂ beÂ usedÂ toÂ betterÂ understandÂ theÂ impactsÂ ofÂ practicesÂ onÂ pollinators.Â ThisÂ chapterÂ includes:Â Â ï· surveyÂ andÂ monitoringÂ protocolsÂ and ï· habitatÂ assessmentÂ toolsÂ toÂ evaluateÂ andÂ prioritize habitatÂ enhancementÂ opportunities. ChapterÂ 10,Â CostâBenefitÂ ConsiderationsÂ forÂ PollinatorÂ ManagementÂ onÂ RoadsidesÂ ThisÂ chapterÂ provides:Â Â ï· stepâbyâstepÂ processesÂ toÂ helpÂ DOTsÂ makeÂ choices aboutÂ actionsÂ thatÂ canÂ supportÂ imperiledÂ pollinators and ï· contextÂ forÂ balancingÂ theÂ costsÂ ofÂ conservationÂ actions withÂ theÂ benefits. ChapterÂ 11,Â CommunicationÂ SupportÂ ThisÂ chapterÂ includes:Â Â ï· plansÂ forÂ communicatingÂ withinÂ DOTsÂ asÂ wellÂ asÂ with theÂ generalÂ publicÂ aboutÂ howÂ individualÂ DOTsÂ are supportingÂ pollinatorsÂ proactivelyÂ and ï· linksÂ toÂ videos,Â recordedÂ presentations,Â aÂ regional slideÂ setÂ thatÂ canÂ beÂ adaptedÂ forÂ agencies,Â andÂ other tools. ChapterÂ 12,Â ReferencesÂ ThisÂ chapterÂ includesÂ bibliographicÂ referencesÂ forÂ materialsÂ citedÂ throughoutÂ theÂ document.Â