Evaluating firefly extinction risk: Initial red list assessments for North America

PLOS ONE RESEARCH ARTICLE Evaluating firefly extinction risk: Initial red list assessments for North America Candace E. Fallon ID1,2*, Anna C. Walker ID2,3, Sara Lewis2,4, Joseph Cicero5, Lynn Faust2,6, Christopher M. Heckscher2,7, Cisteil X. Pérez-Hernández2,8, Ben Pfeiffer2,9, Sarina Jepsen1,2 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 The Xerces Society for Invertebrate Conservation, Portland, Oregon, United States of America, 2 IUCN SSC Firefly Specialist Group, Gland, Switzerland, 3 New Mexico BioPark Society, Albuquerque, New Mexico, United States of America, 4 Department of Biology, Tufts University, Medford, Massachusetts, United States of America, 5 School of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America, 6 Emory River Land Co., Knoxville, Tennessee, United States of America, 7 Department of Agriculture and Natural Resources, Delaware State University, Dover, Delaware, United States of America, 8 Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Michoacán, México, 9 Firefly Conservation and Research, New Braunfels, Texas, United States of America * Abstract OPEN ACCESS Citation: Fallon CE, Walker AC, Lewis S, Cicero J, Faust L, Heckscher CM, et al. (2021) Evaluating firefly extinction risk: Initial red list assessments for North America. PLoS ONE 16(11): e0259379. https://doi.org/10.1371/journal.pone.0259379 Editor: Daniel de Paiva Silva, Instituto Federal de Educacao Ciencia e Tecnologia Goiano - Campus Urutai, BRAZIL Received: May 27, 2021 Accepted: October 18, 2021 Published: November 17, 2021 Peer Review History: PLOS recognizes the benefits of transparency in the peer review process; therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. The editorial history of this article is available here: https://doi.org/10.1371/journal.pone.0259379 Copyright: © 2021 Fallon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the manuscript and its Supporting information files. Fireflies are a family of charismatic beetles known for their bioluminescent signals. Recent anecdotal reports suggest that firefly populations in North America may be in decline. However, prior to this work, no studies have undertaken a systematic compilation of geographic distribution, habitat specificity, and threats facing North American fireflies. To better understand their extinction risks, we conducted baseline assessments according to the categories and criteria of the International Union for Conservation of Nature (IUCN) Red List for 132 species from the United States and Canada (approximately 79% of described species in the region). We found at least 18 species (14%) are threatened with extinction (e.g. categorized as Critically Endangered, Endangered, or Vulnerable) due to various pressures, including habitat loss, light pollution, and climate change (sea level rise and drought). In addition, more than half of the species (53%) could not be evaluated against the assessment criteria due to insufficient data, highlighting the need for further study. Future research and conservation efforts should prioritize monitoring and protecting populations of at-risk species, preserving and restoring habitat, gathering data on population trends, and filling critical information gaps for data deficient species suspected to be at risk. Introduction Effective conservation planning and action depends on identifying the most at-risk species based on their estimated probability of extinction. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species is considered the global standard for estimating the risk of species extinction and can be used as a first step in conservation efforts [1,2]. First established in 1964, major gains have been made in adding new assessments to the Red List in recent years, moving ever closer to the group’s goal of 160,000 assessed species. PLOS ONE | https://doi.org/10.1371/journal.pone.0259379 November 17, 2021 1 / 18 PLOS ONE Funding: CEF and SJ were funded by the Samuel Freeman Charitable Trust, the Edward Gorey Charitable Trust (https://edwardgorey.org/), the New-Land Foundation (http://newlandfoundation. org/), Morningstar Foundation (http:// themorningstarfoundation.com/), and Xerces Society members. ACW was funded by the New Mexico BioPark Society (https://bioparksociety.org/ main/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Extinction risk for North American fireflies Currently, the Red List comprehensively covers charismatic vertebrates, including mammals (91% of all species assessed) and birds (100% of species assessed) [3]. Invertebrates, in contrast, are profoundly underrepresented on the Red List, with just 2% of described species (24,219 out of an estimated 1,478,938) assessed as of 2020 [3]. This gap is even wider for insects: although they represent an estimated 53% of described animal and plant species, only 1% have been assessed [3]. Beetles, a hyper-diverse group of insects with an estimated 386,500 described extant species worldwide [4] have been identified as a priority group for Red Listing due to their species richness, assessment practicality (e.g., relatively stable taxonomy, adequate information available), and economic value [5]. The firefly beetles (family Lampyridae), which contain some 2,200 species globally [4], represent an ideal group for Red List assessments because these charismatic and cosmopolitan insects have the potential to serve as flagship species for invertebrate conservation. They possess diverse life history traits and behaviors and have been the subject of active evolutionary, behavioral, and genetic research [6–10]. Through biomedical research, firefly luciferase has facilitated numerous scientific advances [e.g., 11]. Furthermore, fireflies are culturally, ecologically, and economically important, and because of their sensitivity to light pollution and other environmental degradation, they may be important bioindicators of ecosystem health [12–17]. Some species have been used as biological control agents of unwanted land snails [18]. Long-term surveys have revealed local population declines of the glow-worm Lampyris noctiluca in the U.K. [19,20] and the congregating mangrove firefly Pteroptyx tener in Malaysia [21,22]. In North America, population declines have been anecdotally reported [16], but IUCN Red List assessments had yet to be conducted for any firefly species. A recent review of (...truncated)