Endangered and Threatened Wildlife and Plants; Threatened Species Status With Section 4(d) Rule for Bethany Beach Firefly

SUPPLEMENTARY INFORMATION:

Executive Summary

Why we need to publish a rule. Under the Act (16 U.S.C. 1531 et seq.), a species warrants listing if it meets the definition of an endangered species (in danger of extinction throughout all or a significant portion of its range) or a threatened species (likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range). If we determine that a species warrants listing, we must list the species promptly and designate the species' critical habitat to the maximum extent prudent and determinable. We have determined that the Bethany Beach firefly meets the Act's definition of a threatened species; therefore, we are proposing to list it as such. Listing a species as an endangered or threatened species can be completed only by issuing a rule through the Administrative Procedure Act rulemaking process (5 U.S.C. 551 et seq.).

What this document does. We propose to list the Bethany beach firefly as a threatened species with protective regulations issued under section 4(d) of the Act (a “4(d) rule”) to provide for the conservation of the species.

The basis for our action. Under the Act, we may determine that a species is an endangered or threatened species because of any of five factors: (A) The present or threatened destruction, modification, or curtailment of its habitat or range; (B) overutilization for commercial, recreational, scientific, or educational purposes; (C) disease or predation; (D) the inadequacy of existing regulatory mechanisms; or (E) other natural or manmade factors affecting its continued existence.

We have determined that the Bethany Beach firefly meets the Act's definition of a threatened species due to habitat loss or degradation from the following activities or conditions: under Factor A, urban development and changes in land cover, light pollution, recreational activities, pesticides, invasive plants, and shoreline erosion control (including constructed dunes and sand fencing); and under Factor E, effects of small population size, climate change which includes more frequent and increased storm intensities and high tide flooding, rising sea levels causing periodic and/or total inundation, saltwater intrusion, and increased temperatures and drought).

Section 4(a)(3) of the Act requires that the Secretary of the Interior (Secretary), to the maximum extent prudent and determinable, concurrently with listing designate critical habitat for the species. Section 3(5)(A) of the Act defines critical habitat as (i) the specific areas within the geographical area occupied by the species, at the time it is listed, on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection; and (ii) specific areas outside the geographical area occupied by the species at the time it is listed, upon a determination by the Secretary that such areas are essential for the conservation of the species. Section 4(b)(2) of the Act states that the Secretary must make the designation on the basis of the best scientific data available and after taking into consideration the economic impact, the impact on national security, and any other relevant impacts of specifying any particular area as critical habitat.

We have determined that critical habitat is not determinable at this time for the Bethany Beach firefly. The Act allows the Service an additional year to publish a critical habitat designation that is not determinable at the time of listing (16 U.S.C. 1533(b)(6)(C)(ii)).

Information Requested

We intend that any final action resulting from this proposed rule will be based on the best scientific and commercial data available and be as accurate and as effective as possible. Therefore, we request comments or information from other governmental agencies, Native American Tribes, the scientific community, industry, or any other interested parties concerning this proposed rule. We particularly seek comments concerning:

(1) The species' biology, range, and population trends, including:

(a) Biological or ecological requirements of the species, including habitat requirements for feeding, breeding, and sheltering;

(b) Genetics and taxonomy;

(c) Historical and current range, including distribution patterns and the locations of any additional populations of this species;

(d) Historical and current population levels, and current and projected trends; and

(e) Past and ongoing conservation measures for the species, its habitat, or both.

(2) Threats and conservation actions affecting the species, including:

(a) Factors that may be affecting the continued existence of the species, which may include habitat modification or destruction, overutilization, disease, predation, the inadequacy of existing regulatory mechanisms, or other natural or manmade factors;

(b) Biological, commercial trade, or other relevant data concerning any threats (or lack thereof) to this species; and

(c) Existing regulations or conservation actions that may be addressing threats to this species.

(3) Additional information concerning the historical and current status of this species.

(4) Information to assist with applying or issuing protective regulations under section 4(d) of the Act that may be necessary and advisable to provide for the conservation of the Bethany Beach firefly. In particular, we seek information concerning:

(a) The extent to which we should include any of the Act's section 9 prohibitions in the 4(d) rule; or

(b) Whether we should consider any additional or different exceptions from the prohibitions in the 4(d) rule.

Please include sufficient information with your submission (such as scientific journal articles or other publications) to allow us to verify any scientific or commercial information you include.

Please note that submissions merely stating support for, or opposition to, the action under consideration without providing supporting information, although noted, do not provide substantial information necessary to support a determination. Section 4(b)(1)(A) of the Act directs that determinations as to whether any species is an endangered or a threatened species must be made solely on the basis of the best scientific and commercial data available.

You may submit your comments and materials concerning this proposed rule by one of the methods listed in ADDRESSES . We request that you send comments only by the methods described in ADDRESSES .

If you submit information via https://www.regulations.gov, your entire submission—including any personal identifying information—will be posted on the website. If your submission is made via a hardcopy that includes personal identifying information, you may request at the top of your document that we withhold this information from public review. However, we cannot guarantee that we will be able to do so. We will post all hardcopy submissions on https://www.regulations.gov.

Comments and materials we receive, as well as supporting documentation we used in preparing this proposed rule, will be available for public inspection on https://www.regulations.gov.

Our final determination may differ from this proposal because we will consider all comments we receive during the comment period as well as any information that may become available after this proposal. Based on the new information we receive (and, if relevant, any comments on that new information), we may conclude that the species is endangered instead of threatened, or we may conclude that the species does not warrant listing as either an endangered species or a threatened species. In addition, we may change the parameters of the prohibitions or the exceptions to those prohibitions in the protective regulations issued under section 4(d) of the Act if we conclude it is appropriate in light of comments and new information received. For example, we may expand the prohibitions if we conclude that the protective regulation as a whole, including those additional prohibitions, is necessary and advisable to provide for the conservation of the species. Conversely, we may establish additional or different exceptions to the prohibitions in the final 4(d) rule if we conclude that the activities would facilitate or are compatible with the conservation and recovery of the species. In our final rule, we will clearly explain our rationale and the basis for our final decision, including why we made changes, if any, that differ from this proposal.

Public Hearing

Section 4(b)(5) of the Act provides for a public hearing on this proposal, if requested. Requests must be received by the date specified in DATES . Such requests must be sent to the address shown in FOR FURTHER INFORMATION CONTACT . We will schedule a public hearing on this proposal, if requested, and announce the date, time, and place of the hearing, as well as how to obtain reasonable accommodations, in the Federal Register and local newspapers at least 15 days before the hearing. We may hold the public hearing in person or virtually via webinar. We will announce any public hearing on our website, in addition to the Federal Register . The use of virtual public hearings is consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

On May 15, 2019, we received a petition from the Center for Biological Diversity (CBD) and Xerces Society for Invertebrate Conservation to list the Bethany Beach firefly as an endangered or a threatened species under the Act. In response to the petition, we published a 90-day finding on December 19, 2019 (84 FR 69713), in which we announced our finding that the petition contained substantial information indicating that listing may be warranted for the Bethany Beach firefly.

Peer Review

An SSA team prepared an SSA report for the Bethany Beach firefly. The SSA team was composed of Service biologists, in consultation with other species experts. The SSA report represents a compilation of the best scientific and commercial data available concerning the status of the species, including the impacts of past, present, and future factors (both negative and beneficial) affecting the species.

In accordance with our joint policy on peer review published in the Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 2016, memorandum updating and clarifying the role of peer review in listing and recovery actions under the Act ( https://www.fws.gov/sites/default/files/documents/peer-review-policy-directors-memo-2016-08-22.pdf ), we solicited independent scientific review of the information contained in the Bethany Beach firefly SSA report. We sent the SSA report to five independent peer reviewers and received three responses. Results of this structured peer review process can be found at https://www.regulations.gov. In preparing this proposed rule, we incorporated the results of these reviews, as appropriate, into the SSA report, which is the foundation for this proposed rule.

Summary of Peer Reviewer Comments

As discussed in Peer Review above, we received comments from three peer reviewers on the draft SSA report. We reviewed all comments we received from the peer reviewers for substantive issues and new information regarding the contents of the SSA report. The peer reviewers generally concurred with our methods and conclusions, and they provided additional information, clarifications, and suggestions to improve the SSA report.

I. Proposed Listing Determination

Background

A thorough review of the taxonomy, life history, and ecology of the Bethany Beach firefly ( Photuris bethaniensis) is presented in the SSA report (version 1.0; Service 2024, pp. 4-16). There are at least 15 current known “populations” of the Bethany Beach firefly. Each population exists on a complex of swales (low-lying freshwater marsh areas near coastal dunes) containing at least one occupied swale. The current known range occurs along the Atlantic Coast in Delaware, Maryland, and Virginia (see figure 1, below). This species was only known from Delaware sites until discovery of Maryland populations in 2020, and Virginia populations in 2021. Additional populations may exist due to limited survey efforts. It is possible that the species occurs in additional swales or complexes, or on additional properties ( e.g., publicly owned land), where there is similar habitat and plant communities (Edinger et al. 2014, p. 13 (New York); Breden et al. 2001, p. 109 (New Jersey); Shafale 2012, p. 185 (North Carolina); Nelson 1986, p. 26 (South Carolina)). Comparable interdunal swale habitats exist as far north as New York and as far south as South Carolina. Development of the Atlantic Coast has decreased the availability of swale habitat and the number of populations within the known current range (Delaware, Maryland, and Virginia).

Figure 1. The seven properties across Delaware, Maryland, and Virginia where the Bethany Beach firefly occurs. The percentages after the property name refer to the percent of the rangewide occupied swales that are present on that property. Delaware populations were discovered in 1998, and Maryland and Virginia populations were discovered in 2020 and 2021, respectively.

Bethany Beach firefly is a nocturnal firefly characterized by two bright green flashes given off by males to attract females for mating, while females flash or emit a low glow in response. Like other beetles, fireflies complete metamorphosis with four distinct life stages: egg, larva, pupa, and adult. The longest stage is the larval stage (Fallon et al. 2022, p. 5, Lloyd 2018, pp. 5-7; Faust 2017, p. 39). Adult Bethany Beach fireflies are active from mid-late June through early-mid August and emerge well after sunset.

Bethany Beach fireflies occupy freshwater swales that form as groundwater and rain collect in shallow depressions between or behind coastal sand dunes. These communities are dynamic systems and are susceptible to saltwater intrusion and shifting sand formations. Water levels within the swales vary from standing water to saturated soil, and they can become flooded or dry out completely. Suitable swale habitat is dependent on an intermediate stage of succession (woody and herbaceous open swales) that is naturally driven by periodic dune overwash from storm surge.

Overall, this species requires adequate temporally stable swale habitat that typically has woody shrubs along the perimeter and that retains shallow freshwater seasonally. Moisture is needed for all of the life stages to prevent desiccation, provide food sources, and provide ample organic matter for overwintering and sheltering habitat for larvae. Sufficient population size and connectivity are needed to maintain genetic diversity and to support reproduction and recruitment within a population.

Regulatory and Analytical Framework

Regulatory Framework

Section 4 of the Act (16 U.S.C. 1533) and the implementing regulations in title 50 of the Code of Federal Regulations set forth the procedures for determining whether a species is an endangered species or a threatened species, issuing protective regulations for threatened species, and designating critical habitat for endangered and threatened species.

The Act defines an “endangered species” as a species that is in danger of extinction throughout all or a significant portion of its range, and a “threatened species” as a species that is likely to become an endangered species within the foreseeable future throughout all or a significant portion of its range. The Act requires that we determine whether any species is an endangered species or a threatened species because of any of the following factors:

(A) The present or threatened destruction, modification, or curtailment of its habitat or range;

(B) Overutilization for commercial, recreational, scientific, or educational purposes;

(C) Disease or predation;

(D) The inadequacy of existing regulatory mechanisms; or

(E) Other natural or manmade factors affecting its continued existence.

These factors represent broad categories of natural or human-caused actions or conditions that could have an effect on a species' continued existence. In evaluating these actions and conditions, we look for those that may have a negative effect on individuals of the species, as well as other actions or conditions that may ameliorate any negative effects or may have positive effects.

We use the term “threat” to refer in general to actions or conditions that are known to or are reasonably likely to negatively affect individuals of a species. The term “threat” includes actions or conditions that have a direct impact on individuals (direct impacts), as well as those that affect individuals through alteration of their habitat or required resources (stressors). The term “threat” may encompass—either together or separately—the source of the action or condition or the action or condition itself.

However, the mere identification of any threat(s) does not necessarily mean that the species meets the statutory definition of an “endangered species” or a “threatened species.” In determining whether a species meets either definition, we must evaluate all identified threats by considering the species' expected response and the effects of the threats—in light of those actions and conditions that will ameliorate the threats—on an individual, population, and species level. We evaluate each threat and its expected effects on the species, then analyze the cumulative effect of all of the threats on the species as a whole. We also consider the cumulative effect of the threats in light of those actions and conditions that will have positive effects on the species, such as any existing regulatory mechanisms or conservation efforts. The Secretary determines whether the species meets the Act's definition of an “endangered species” or a “threatened species” only after conducting this cumulative analysis and describing the expected effect on the species.

The Act does not define the term “foreseeable future,” which appears in the statutory definition of “threatened species.” Our implementing regulations at 50 CFR 424.11(d) set forth a framework for evaluating the foreseeable future on a case-by-case basis, which is further described in the 2009 Memorandum Opinion on the foreseeable future from the Department of the Interior, Office of the Solicitor (M-37021, January 16, 2009; “M-Opinion,” available online at https://www.doi.gov/sites/doi.opengov.ibmcloud.com/files/uploads/M-37021.pdf ). The foreseeable future extends as far into the future as the U.S. Fish and Wildlife Service and National Marine Fisheries Service (hereafter, the Services) can make reasonably reliable predictions about the threats to the species and the species' responses to those threats. We need not identify the foreseeable future in terms of a specific period of time. We will describe the foreseeable future on a case-by-case basis, using the best available data and taking into account considerations such as the species' life-history characteristics, threat projection timeframes, and environmental variability. In other words, the foreseeable future is the period of time over which we can make reasonably reliable predictions. “Reliable” does not mean “certain”; it means sufficient to provide a reasonable degree of confidence in the prediction, in light of the conservation purposes of the Act.

Analytical Framework

The SSA report documents the results of our comprehensive biological review of the best scientific and commercial data regarding the status of the species, including an assessment of the potential threats to the species. The SSA report does not represent our decision on whether the species should be proposed for listing as an endangered or threatened species under the Act. However, it does provide the scientific basis that informs our regulatory decisions, which involve the further application of standards within the Act and its implementing regulations and policies.

To assess the Bethany Beach firefly's viability, we used the three conservation biology principles of resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 306-310). Briefly, resiliency is the ability of the species to withstand environmental and demographic stochasticity (for example, wet or dry, warm or cold years); redundancy is the ability of the species to withstand catastrophic events (for example, droughts, large pollution events); and representation is the ability of the species to adapt to both near-term and long-term changes in its physical and biological environment (for example, climate conditions, pathogens). In general, species viability will increase with increases in resiliency, redundancy, and representation (Smith et al. 2018, p. 306). Using these principles, we identified the species' ecological requirements for survival and reproduction at the individual, population, and species levels, and described the beneficial and risk factors influencing the species' viability.

The SSA process can be categorized into three sequential stages. During the first stage, we evaluated the individual species' life-history needs. The next stage involved an assessment of the historical and current condition of the species' demographics and habitat characteristics, including an explanation of how the species arrived at its current condition. The final stage of the SSA involved making predictions about the species' responses to positive and negative environmental and anthropogenic influences. Throughout all of these stages, we used the best available information to characterize viability as the ability of a species to sustain populations in the wild over time, which we then used to inform our regulatory decision.

The following is a summary of the key results and conclusions from the SSA report; the full SSA report can be found at Docket No. FWS-R5-ES-2024-0080 on https://www.regulations.gov .

Summary of Biological Status and Threats

In this discussion, we review the biological condition of the species and its resources, and the threats that influence the species' current and future condition, in order to assess the species' overall viability and the risks to that viability.

Species Needs

The SSA report contains a detailed discussion of the Bethany Beach firefly's individual and population requirements (Service 2024, pp. 14-16); we provide a summary here. Based upon the best available scientific and commercial information, and acknowledging existing ecological uncertainties, the resource and demographic needs for breeding, feeding, sheltering, and dispersal of the Bethany Beach firefly are characterized as:

(1) Sufficient quality and availability of interdunal swale habitat with moist soil, herbaceous vegetation, woody vegetation surrounding the swales, and decaying wood to support all life stages of Bethany Beach fireflies and their food sources.

(2) Sufficient quantities of snails, worms, and other soft-bodied invertebrates, and plant material such as berries, as food sources for Bethany Beach firefly larvae.

(3) Sufficient quantities of Bethany beach firefly individual adult males and females to be able to flash to find and select mates, copulate, oviposit, and disperse.

(4) Sufficient connectivity of habitat (swales within 1,000 feet (304.8 meters) of other occupied swales) to allow Bethany beach firefly populations to repopulate each other after catastrophes such as major coastal storms. Based on observations of flight patterns of this species, we assume that swales within 305 m (1,000 feet) of each other are close enough that individuals could travel this distance and reproduction and gene flow could occur between them (Service 2024).

(5) Sufficient stable (open) swales filled with ample organic matter, which provides overwintering and sheltering habitat for Bethany Beach firefly larvae.

Bethany Beach firefly abundance depends on the availability and condition of these resources in freshwater interdunal swales in proximity to the Atlantic shoreline.

Threats

A thorough review of the threats affecting the Bethany Beach firefly is presented in chapter 4 of the SSA report (version 1.0, Service 2024, pp. 17-35). The main threats affecting the Bethany Beach firefly are related to urban development and changes in land cover, light pollution, recreational activities, pesticides, invasive plants, shoreline erosion control (including constructed dunes and sand fencing), effects of small population size, climate change which includes more frequent and increased storm intensities and high tide flooding, rising sea levels causing periodic and/or total inundation, saltwater intrusion, and increased temperatures and drought. Habitat loss, degradation, and fragmentation due to urbanization and development has caused populations to be isolated with presumably no genetic transfer among them, leaving these small populations at increased risk of impacts from random stochastic and unforeseen catastrophic events. The compounding effects of climate change include increased temperatures and drought, which could dry out swales, and increased storm frequency and intensity, which could degrade swale habitat due to excessive overwash and storm surges. Rising sea levels also pose a risk to first degrade and then remove habitat due to saltwater intrusion from swales being inundated periodically with the addition of storm surge, and then total inundation at some height above current sea levels.

Habitat Loss, Fragmentation, and Degradation

Development —Because the Bethany Beach firefly is believed to be a habitat specialist restricted to interdunal freshwater swales and likely has limited dispersal (Lewis et al. 2020, p. 159), destruction and degradation of swales result in the loss of or decline in populations and decreases connectivity between populations. Sandy ocean beaches are some of the most popular tourist and recreational areas, and constitute some of the most valuable real estate, in the United States (Hapke et al. 2011, p. 2). These Atlantic coastal areas are the sites of high-density residential and commercial development, despite the frequent natural hazards that can occur, including flooding, storm impacts, and coastal erosion. Extensive areas along the Atlantic Coast (Bethany Beach and Dewey Beach, Delaware; Ocean City, Maryland; and Virginia Beach, Virginia) likely contained additional swale habitat prior to development that primarily occurred between 1950 and 1970 after the completion of the Chesapeake Bay bridges (Delaware Department of Natural Resources and Environmental Control 2004, p. 27). There is evidence that the populations of Bethany Beach firefly in Delaware are much reduced from their historical levels. The two sites where the Bethany Beach firefly was originally observed and described by McDermott (1953, p. 35) near Bethany Beach, Delaware, have been lost to development (Lloyd 2018, p. 93). Surveys conducted from 1998 to 2000 in Delaware (Hecksher and Bartlett 2004, pp. 349-352) found the species in swales in three State parks but also in a swale located on privately owned land in the Tower Shores Beach Community (Tower Shores) (Hecksher and Bartlett 2004, pp. 349-352). The swale in Tower Shores was one of the largest-known global populations, consisting of an estimated 100 or more adults in the 1990s. The property was recently developed in 2019, and the population that was previously there is now believed to be extirpated. In that area, an elevated roadway has altered hydrology and creates shade, while a cul-de-sac has been built over the entire swale, and lighting from the houses has degraded the surrounding area; no fireflies have been observed in surveys since construction was finished.

State laws in Delaware, Maryland, and Virginia do not prevent destruction of the swales via development. Non-tidal wetlands under 400 acres (161.87 hectares) in size are not regulated in Delaware (see the Delaware Wetlands Act, in title 7 of the Delaware Code at chapter 66, section 6603(h); and the Wetlands Regulations, in title 7 of the Delaware Administrative Code at 7502). Since many of the swales where the firefly occurs are smaller than 400 acres, the Delaware Wetlands Act does not regulate development of the swales. Non-tidal wetland laws are stronger in Maryland and Virginia, but some suitable firefly habitat that occurred historically was likely lost due to development (Ocean City, Maryland; Virginia Beach, Virginia) prior to these laws being established. The Maryland Non-Tidal Wetlands Act (1989) limits development in and around tidal wetlands (see title 5 of the Maryland Code, “Environment,” at section 5-907). Similarly, in Virginia, developers must obtain a water protection permit before disturbing any wetland, tidal or non-tidal, or stream by clearing, filling, excavating, draining, or ditching (see article 2.2 of the Virginia Code at section 62.1-44.15:20). Although non-tidal wetland laws are stronger in Maryland and Virginia, there is still loss of habitat when permits are issued for development. However, the significant habitat loss that occurred prior to these regulations being enacted has likely limited the Bethany Beach firefly's distribution in these States.

Bethany Beach fireflies are made more vulnerable by their populations' relative isolation from one another. Based on observations from surveys conducted for the species since 2019, we find that fireflies can disperse from occupied swales to other interdunal swales and upland areas located within 1,000 feet (Davis, J. 2023c). The known extant populations in the Delaware State Parks have connectivity within each park but not among the parks due to development of the shoreline between State parks. The Delaware State Parks are also separated from Assateague Island National Seashore due to development and open water. While Assateague Island National Seashore, Chincoteague National Wildlife Refuge, and the National Aeronautics and Space Administration's (NASA's) Wallops Island Flight Facility are in proximity to one another in Maryland and Virginia, and are not separated by developed areas, dispersal of individuals among these properties is not known to occur due to the distances of occupied swales from each other. False Cape State Park is to the south near the North Carolina/Virginia border and is not close to any other known populations of Bethany Beach fireflies. Without additional suitable habitat occurring within the dispersal distance of the species, it is unlikely that the Bethany Beach firefly could relocate if its habitat is destroyed (Lewis et al. 2020, p. 159).

Even in the parts of their range that are protected from development, Bethany Beach fireflies also face indirect impacts, such as habitat degradation. With the exception of NASA's Wallops Island Flight Facility, which does not allow public access to the shoreline, the sites in which the species is currently present occur primarily on public lands that receive high numbers of visitors for recreational use of the beaches and that border developed areas. As a result, the habitat in these areas is not pristine: the public lands themselves have significant infrastructure (such as parking lots, roads, trails, bathrooms, and visitor centers), and these parks are also adjacent to residential development at varying densities, with the highest densities occurring adjacent to the Delaware State Parks. Both in-park and adjacent development or infrastructure could destroy or degrade swales, alter swale hydrology, degrade water quality, and decrease connectivity among or between swales. Maintenance operations conducted in the past at the three Delaware State Parks may have impacted, drained, or filled in interdunal swales, notably some with populations of the Bethany Beach firefly or other firefly species of conservation concern. Several swales in which the species is present show evidence of filling, ditching, mowing, dumping, and heavy equipment use (Davis 2023d, pers. comm.).

However, impacts from development are not equally distributed among all public lands where occupied swales occur. Development is less of a threat where the species occurs in Maryland and Virginia because the density of development surrounding the properties is low. Assateague Island National Seashore is separated from the mainland of Maryland by Chincoteague Bay; therefore, it is not adjacent to any development occurring outside of the park. There is very little infrastructure ( e.g., lights, roads, and buildings) throughout Assateague, although there are roads and lights from a drive-in campground adjacent to one swale complex. There is also little infrastructure near the occupied swales at Chincoteague National Wildlife Refuge and False Cape State Park in Virginia, and only a two-lane road and some buildings occur adjacent to the three occupied swale complexes at NASA's Wallops Island Flight Facility. This is in contrast to Delaware, which has more infrastructure in the parks, a major highway visible from almost all of the swales running adjacent to two of the parks (Delaware Seashore State Park and Fenwick Island State Park), and a higher density of residential development surrounding the parks. However, four populations at Assateague Island National Seashore and all the populations at NASA's Wallops Island Flight Facility remain vulnerable due to altered hydrology from roads, which is evident due to the presence of the nonnative plant species Phragmites australis (often called Phragmites, or common reed) in those swales (for more information, see Invasive Plant Species, below).

Currently, the greatest threat of development is at Delaware Seashore State Park, where a lease granted for a desalinization project could entail directional drilling adjacent to an occupied swale and two proposed offshore wind projects (Maryland Wind and Skipjack Wind) with possible landfall locations (named “3Rs” and “Tower Road”) for the cable route occurring near interdunal swales. It is anticipated that the two wind projects will be constructed within the next 10 years. It is unknown whether directional drilling has occurred at the desalinization plant at this time. For the Maryland Wind biological opinion, the project description includes avoiding land disturbance, including horizontal directional drilling, within 100 feet of any swale; a time-of-year restriction for the use of any light sources between June 1 and September 1 for any work at the 3Rs parking lot or Tower Road parking lot proposed landfall sites; and avoiding installation of permanent light fixtures at the Tower Road site. With these measures, there would be no anticipated impacts to the Bethany Beach firefly. The Service has not gone through section 7 consultation yet on Skipjack Wind.

Development can disrupt the groundwater regimes that sustain interdunal swales both directly and indirectly. Development directly affects the hydrology of swales by increasing impervious surfaces and compacting soils in adjacent areas, thereby reducing groundwater recharge and eventually lowering the water table (Wright et al. 2006, p. 22). Indirectly, development results in depletion of groundwater by increasing the number of groundwater users in the area. A decrease in groundwater recharge will lower the water table and could result in swales becoming drier over time which could affect the ability of larvae and their prey to survive in the soil. Alteration of hydrology can also lead to an increase in invasive plants and woody vegetation, a change in herbaceous vegetation, and succession in the wetland, resulting in loss of wetland habitat over time. Development adjacent to the properties in which the Bethany Beach firefly occurs is greatest in Delaware (Delaware Seashore State Park and Fenwick Island State Park).

Stressors on groundwater supply are projected to increase in the future throughout the range of the Bethany Beach firefly. Within the U.S. Geological Survey's hydrologic unit code (HUC) 4 (HUC 4 focuses on watersheds in a subregion), in the Delaware-Mid Atlantic Coastal basin (which includes coastal areas of Delaware, Maryland, and Virginia), where a majority of the swale complexes are found, freshwater yield (from surface or ground water) is predicted to decrease by 10 percent while the demand is expected to increase 80 to 100 percent between 2046 and 2070 (when compared to a baseline from 1985-2010) (Brown et al. 2019, p. 225). Much of this is driven by climate change, and its effect on water use in multiple sectors, like agriculture (increased evapotranspiration) and energy use (increased temperatures) (Brown et al. 2019, p. 226). Demands higher than yields can result in reduced groundwater storage, which can reduce the quantity and quality of available swale habitat and decrease the resiliency of the Bethany Beach firefly.

Light Pollution —Firefly species, including the Bethany Beach firefly, rely on bioluminescent light to find mates and to ward off predators. Each species has a unique flash color, length, and frequency. Both male flash patterns and female response patterns are species-specific to prevent hybridization (Lloyd 1966, p. 65; Stanger-Hall and Lloyd 2015, in Owens et al. 2022, p. 2). Courtship dialogues are thought to be essential for mate success in nocturnal fireflies, as the males of most species are presumed not to use visual (color) or chemical (pheromone) cues and thus have no other method of locating receptive females (Demary et al. 2005, in Owens et al. 2022, p. 2).

Artificial light changes the night-time ambient brightness, which can change the intensity and timing of firefly flashes (Owens and Lewis 2018, p. 13). Bethany Beach fireflies are phototactic, which means they are attracted to light of any kind, including artificial light (Lloyd 2018, p. 94). Artificial light at night can reduce reproduction by affecting mating signals, which prevents mates from finding each other or prevents males from receiving the correct light cues to begin their nocturnal flashing display or both (Lewis et al. 2020, pp. 160-161).

Light pollution is more of an issue in the Delaware State Parks, which are adjacent to development and infrastructure. Light pollution occurs at all three Delaware State Parks in more than 50 percent (26 of 52) of the occupied swales. There is little light pollution where the species occurs in Maryland and Virginia.

Recreation and Grazing —Because the species' occurrence is almost entirely on State or Federal parkland where visitation is high due to recreational use of the beach, there is the potential for foot traffic in the dunes, which could result in beachgoers trampling adults and larva. However, trampling by humans may be limited because the swales are wet, occupied by mosquitoes, and often surrounded by woody vegetation or invasive vegetation such as Phragmites. Trampling of adult females and larvae, destruction of microhabitat that supports fireflies, and increased light pollution have been identified as risks associated with increased numbers of visitors in parks in other parts of the country (Faust 2010, pp. 213, 215; Lewis et al. 2020, pp. 163-164).

In Delaware, there is a dune crossing located 350 feet (106.68 meters) from a swale in which the Bethany Beach firefly is present (Davis 2023d, pers. comm.). At Assateague Island National Seashore in Maryland, there are six dune crossings located near a campground that are adjacent to swale habitat where the species is present. However, all the other swale habitat where the species is present is in areas of the island that do not have camping. Thus, even if trampling occurred to some extent, the number of locations where it occurs is limited. There are also ponies on the island that freely graze throughout the park and walk through the swales, which could damage the soil and vegetation more than would be expected from visitors walking through the swales (Huslander 2023, pers. comm.). Grazing could also result in crushing individual eggs and larvae in the soil. However, ponies likely do not impact the species at the population level since ponies are not constantly grazing in swales, and this is not the only habitat ponies visit. In other words, impacts to swales by ponies are believed to be limited or temporary or both. There is little potential for impacts from recreation at NASA's Wallops Island Flight Facility in Virginia, and while Chincoteague National Wildlife Refuge does have visitation by people, trails for visitors are not in the area where the Bethany Beach firefly occurs (Holcomb 2023, pers. comm.).

Pesticide Use —Pesticides are substances that are used to control pests; pesticides include herbicides, which are used to control vegetation, and insecticides, which are used to control insects. Both herbicides and insecticides have the highest use in agriculture. While some agricultural pesticides have shown negative affects to fireflies in laboratory studies (Wang et al. 2022, entire; Pearsons et al. 2021, entire), the exposure of Bethany Beach fireflies to agricultural use of pesticides is minimal at most. Bethany Beach fireflies occur on barrier islands or within 500 meters (1,640 feet) of the coastline. These areas do not have agriculture nearby. On barrier islands, there is extensive separation from mainland agricultural areas. There may be some garden and home use of pesticides in beach communities on the barrier islands, but the overall use in these areas would be relatively small and the sites occupied by Bethany Beach firefly are primarily on undeveloped public land. Thus, we do not view agricultural pesticide use as a threat to Bethany Beach firefly.

The main source of Bethany Beach firefly exposure to pesticides is through spraying to control mosquitoes in some areas and some limited herbicide use. Although only a few studies have investigated direct effects of herbicides and insecticides on fireflies, broad-spectrum insecticides are known to adversely affect numerous nontarget insects and other taxa (reviewed by Sanchez-Bayo 2011, pp. 74-76; Pisa et al. 2015, pp. 82-83).

Herbicides —The Bethany Beach firefly faces a moderate threat from herbicides. There is some control of Phragmites in interdunal swales at Assateague National Seashore, and exposure to herbicides could occur from control of invasive vegetation in and near swales. We expect exposure would be low because the only park that reported control of invasives in interdunal swales was Assateague Island National Seashore. Imazapyr and glyphosate are active ingredients commonly used to control the invasive vegetation using high-pressure or low-pressure foliar spray application, primarily during the fall months, although imazapyr can be used at any time during the growing season. There is no literature that suggests that there are direct impacts to Bethany Beach firefly from the use of glyphosate and imazapyr, but indirect impacts could cause a reduction in Bethany Beach firefly prey. Some surfactants used in the application of glyphosate and imazapyr to increase efficacy of these two herbicides are more toxic to fish and aquatic invertebrates than glyphosate and imazapyr themselves (Brodman et al. 2010, pp. 80-81; Sinnott 2015, pp. 33-34; Breckels and Kilgour 2018, p. 4; Sinnott 2015, entire). The surfactant polyethoxylated tallowamine (POEA), which is used in glyphosate-based herbicides, has been found to cause the direct mortality of amphibians (Brodman et al. 2010, pp. 70, 80-81). A study of the aquatic surfactant, nonylphenol-polyethylene (NPE), was also found to be moderately toxic to amphibians at concentrations under 1.2 milligrams per liter (mg/L); however, more research is needed (Brodman et al. 2010, pp. 70, 80-81). Based on these results, there could be the potential for indirect effects to the Bethany Beach firefly from the use of surfactants with glyphosate or imazapyr through impacts to food sources. However, at this time, there is little exposure overall from herbicide use across the Bethany Beach firefly's range.

Insecticides for Mosquito Control —The Bethany Beach firefly's exposure to organophosphate adulticides for mosquito control varies across its range. Mosquito spraying is not conducted on Assateague Island National Seashore in Maryland or at the Virginia park properties where the species occurs (see table 3, below). However, there is some spraying in areas at NASA's Wallops Island Flight Facility and at the Delaware State Parks. At Wallops Island, the Bethany Beach firefly's exposure to these insecticides is likely low because spraying is only applied on the grass and local brush and not in waterways or storm drain/outfall areas (Levine 2023, pers. comm.).

Delaware uses two mosquito control chemicals. Within the Delaware State Parks, the current agreement with Delaware Division of Fish and Wildlife (DFW) is that there is no spraying of adulticides between June 15 and August 15, when adult Bethany Beach fireflies are most active. During this time, DFW uses Bti, which targets mosquito larvae. Bti (short for Bacillus thuringiensis subsp. israelensis) is a naturally occurring bacterium found in soils and targets only the larvae of the mosquito, blackfly, and fungus gnat ( https://www.epa.gov/mosquitocontrol/bti-mosquito-control##4 ). Bti is considered very safe because it targets only specific insects.

Outside the June 15 to August 15 timeframe, Delaware has used Trumpet EC^TM, a common chemical for mosquito control with an active ingredient called naled. Trumpet EC^TM is derived from phosphoric acid and is highly toxic to fish resources and a wide range of aquatic non-target organisms including mayflies, caddisflies, crustaceans, fresh and saltwater chironomids, and other marine invertebrates. Organophosphates are also highly toxic to terrestrial insects and aquatic beetles that are naturally occurring predators of mosquito larvae (Laskowski et al. 1999, p. 742; Pinkney et al. 2000, p. 678).

While we do not have data on the effects of Trumpet EC^TM specifically on fireflies, Bethany Beach fireflies still occur in swales that have been sprayed by this chemical. Table 1 below describes the swales that have been sprayed over time, mostly in Delaware Seashore State Park, likely because they are near some park facilities. Swales 700, 701, 702, 703 have been sprayed in 11 of the 12 events described in table 1, starting in 2013 and continuing into 2023. All four swales continue to have Bethany Beach firefly presence with the most recent years of observation being 2021, 2023, 2020 and 2022, respectively. While more information would be helpful, the best available information does not show harmful effects of the Delaware spray regime to Bethany Beach firefly populations.