Why parks are a critical component of firefly conservation
Fireflies. Lightning bugs. Glow-worms. Just the names alone are enough to stir the hearts of kids anywhere, and perhaps even incite a little passion in adults as well. There is something magical about venturing out at dusk and seeing a field full of gently pulsing lights in the grass and in the forest, beckoning you even further into the night to discover its mysteries. It is no exaggeration to say that a large part of discovering the wonder of nature for many people began when they saw fireflies as kids. Fireflies display one of nature’s most intriguing phenomena — bioluminescence, that is, the emission of cold light by living organisms. Cold light in fireflies and other species is produced by a light-emitting molecule, called luciferin, which is activated by an enzyme called luciferase.
While bioluminescence is not common in terrestrial environments, it is abundant in the sea. More than three quarters of marine organisms display some form of bioluminescence for communicating, finding prey and even camouflaging themselves.
But on land, in early and mid-summer, it’s fireflies that put on the show.
What Are Fireflies?
Fireflies are not flies at all, but beetles that are mostly nocturnal flying members of the Lampyridae family, which also includes glow-worms and the tortuously named daytime dark fireflies that don’t flash at all in the night, but rather attract their mates in the day by powerful chemical pheromones. There are about 2,000 species of fireflies worldwide, and approximately 170 species are found within North America. Most occur east of the Rockies, but there are some species that occur in the West as well.
Fireflies, like all beetles, undergo a full metamorphosis during their life cycle — egg, pupa, larva and adult. This is a cycle that might last from a couple of months to a couple of years. During the larval phase, fireflies prey on soft-bodied invertebrates, such as worms and grubs, which they find in leaf litter and moist soils until they pupate into adults in the late spring or early summer. They may only live a few weeks to mate and begin the cycle all over again.
Some firefly species don’t flash as adults, but in others, the flightless adult females produce a long-lasting, continuous glow to attract mates. Most species, however, exchange flashes during dark hours to find their mates — the male flies about and flashes in a particular pattern, while the female perched on tall grasses or tree branches signals her receptiveness with a brief flash.
Flashing patterns vary substantially, but one species, Photinus carolinus, puts on one of the most fascinating light shows in nature — synchronous flashing in which all the adult fireflies flash at the same time. This natural spectacle only occurs in a couple of locations in the United States. In the Great Smoky Mountain National Park, it has become so popular that visitors hoping to see it can only gain access to that area of the park by annual lottery.
Threats to Fireflies
A new study, titled “A Global Perspective on Firefly Extinction Threats,” published in the February 2020 issue of the journal BioScience, reports the results of a survey of international firefly experts who were asked to identify the greatest threats to firefly populations in eight geographic regions of the world. The most serious threats to fireflies, according to these scientists, were loss of habitat, light pollution and pesticides, with drought, flooding and extreme temperatures as lesser, but still very significant, threats. Unsurprisingly, a number of these factors link to climate change conditions.
The greatest threats in the eastern United States, which is the area of North America with the greatest number of species of fireflies, involve habitat destruction. “The loss of firefly habitat occurs mainly through urbanization and commercial and residential development,” the report states.
Artificial light at night, called ALAN, is a major form of manmade light pollution and the second-most serious threat to fireflies. Because most firefly species depend on flash dialogues between the male and female for courtship, light pollution interferes with mating success.
Pesticide use, ranked as the third-most serious threat, is also the least understood cause of the decline of fireflies. There are few comprehensive studies investigating the impacts of insecticides and herbicides on the larval and adult forms of fireflies. Candace Fallon, senior conservation biologist for the Xerces Society, says that there are few firefly-monitoring programs in the United States. “There are so many holes in our knowledge,” she says. “There is a lot we don’t know.”
Parks Can Help Save Fireflies
In interviewing several firefly experts for this article, there was one thing they all agreed on: Parks may be one of the best ways to contribute to firefly conservation. Emeritus professor of entomology Larry Buschman of Kansas State University, the author of Field Guide to Western North American Fireflies, says, “People love to visit where fireflies are. They are a charismatic species of wildlife. When people get out to appreciate and value fireflies in parks, then we can get conservation going. And when we do, we can help educate the public as well.”
Fallon agrees. “Fireflies are in trouble,” she says. “They need conservation. Parks have a lot of opportunity to conserve fireflies. The greatest threat to fireflies is loss of habitat and degradation of existing habitat. The most important thing we can do to conserve fireflies is to protect and restore habitat.”
Some park agencies already are working to conserve fireflies and educate the public about them. Katrina Arnold of Five Rivers MetroParks in Dayton, Ohio, says they have an extensive program for families that engages children and youth in firefly education and conservation. Their free program, funded by the Cox Arboretum Foundation, is offered to kids ages 3 to 13. The program has three phases, beginning with the Discover level. It progresses to the Act level, in which kids participate in Firefly Watch, a citizen science program. The third level, Share, is designed to get kids excited about conservation in an active way “without feeling nerdy,” according to Arnold. They are encouraged to come back to the program, talk to other kids about what they learned and share their stories. The agency has received great feedback from participating families for this innovative program.
Bill Hagenbuck, senior park naturalist at Martin Park Nature Center in Oklahoma City, says they used to offer very well-
attended firefly hikes in June and July each year, but in recent years, they had to stop because there was a sharp decline in firefly numbers. The 144-acre park, which features a nature center, was an old dairy farm with a variety of habitats, including a mix of open meadows and forested areas. “It seems it would be just about [an] ideal habitat for fireflies,” Hagenbuck says. However, the park has become “an encapsulated oasis in the city.” Today, a turnpike, apartment buildings, a large medical building and a residential neighborhood surround the park. Hagenbuck says they hope to restore fireflies to the park by increasing quality habitats for them. One method they are trying includes prescribed burns to eradicate Johnson grass, a noxious weed that has taken over some of the grasslands in the park. “We are hoping to bring back our firefly programs,” he says. “They were extremely popular and maxed out every time we offered them. People just don’t get a chance to do something like that anymore.”
In Arlington County, Virginia, however, it is another story, according to Rachael Tolman, park naturalist. For 10 years, they have conducted an annual firefly festival with crafts and games and exhibits about fireflies. For the 250 to 500 people who attend this extremely popular festival, a firefly watching party follows the daytime portion of the event. Tolman notes, “We are super urban, but we try to keep diversified habitats in our parks, which benefit firefly populations.” Their resource management goals include creating new habitat areas, removing invasive plant species and managing to allow the native landscape and plants to recover. “If we are doing best practices for fireflies, we are doing best practices for all wildlife,” she says.
Conserving Fireflies and Educating the Public
If firefly conservation in parks is to be successful, education must be an essential component of your conservation objectives. Park and recreation agencies already engaging in successful firefly conservation activities also have committed to public education and awareness activities in nature centers, on night hikes and in educational exhibits.
Knowledge of the firefly species you have in your locality is critical, especially if you plan to begin any longer-term conservation efforts. This may not be as simple as it sounds and if there isn’t knowledgeable staff, agencies should look for firefly experts in the ranks of their citizen volunteers and at local universities. Hiring a consultant may be a good course of action to help you locate best habitat areas, identify the species in your locale and to assist in drafting a management plan, especially if you do not have those capabilities and knowledge in-house.
Buschman, who has studied fireflies for decades, says he has a pet peeve. “Public agencies put curfew restrictions on parks, so that people cannot enter after dark. We cannot get people interested in watching fireflies and then prohibit them from watching them!” He lobbies to keep parks open longer, at least during the peak time of firefly courtship. There is a lot of truth to what he says. Educating the public about watching wildlife at night means we might have to add limited public access after dark to any management plan along with other objectives.
Creating Ideal Firefly Habitats
What should ideal firefly habitats look like in parks? It depends on the biogeographical characteristics of your parks, but four or five things are necessary, according to Fallon. “Ideally, you should have varied habitats within your parks that are a little wild, not manicured. It depends on the firefly species you have locally, too. Some like open meadows; some need forested land. You still need diversity within those habitats and micro-habitats within those,” she says. “Dark nights are important!” It is one reason she believes parks are ideal places for fireflies to thrive. However, park managers need to evaluate their outdoor lighting and consider what lights might be reduced or turned off during firefly mating season.
Quality habitats can vary quite a bit, but year-round moisture is essential, according to all firefly experts consulted. Whether it is moist woods, stream valley floodplains, non-tidal wetlands or even wet meadows — moisture is critical, especially for the juvenile stages. Fallon and others speculate that prolonged droughts in the West and Southwest may be seriously affecting firefly populations, which are prone to desiccation, that is, the severe drying out of larval and adult stages, in extremely dry conditions.
Pesticides may be a serious threat to fireflies, but few studies have been conducted. Many park agencies are moving toward a much more thoughtful and limited use of pesticides. The use of weed-killing herbicides, such as Roundup and other glyphosate-based herbicides, have generated intense public interest and opposition due to fear of human health impacts and effects on the environment. Integrated Pest Management programs are limiting the amount and type of pesticides applied in parks, and many agencies are looking for organic herbicides and flame and foam (steam) treatments that are less toxic. All these actions to reduce pesticide use can only help the cause of firefly conservation.
Conserving fireflies in parks will address several conservation objectives. It will enhance habitat for species that are in need of conservation. It will provide exciting new opportunities for staff and citizen science volunteers to explain a part of the natural world to the public — something that will slip away forever, unless we take effective action now to save it from disappearing. And, it is the right thing to do for these mysterious, elusive species that enrich the lives of all who see them flashing in the darkness of night and leave us wondering why and how they do.
Tune in to the April bonus episode of Open Space Radio to hear Dolesh and Michele White of NRPA’s conservation team talk about managing parks for fireflies and engaging the public at the Open Space website or on your favorite podcast app.
Five Things You Can Do to Make Your Parks More Firefly Friendly
- Mow grasslands and meadow habitat in rotational strips or a mosaic pattern. (This is great for pollinators, too.)
- Create more meadows and more edge habitat. Leave a grass buffer strip around forest edges.
- Try to create more moisture year-round, if possible. Plant green infrastructure areas with pollinators and fireflies in mind.
- Leave forested areas natural. Allow more leaf litter and leave downed trees in place.
- Evaluate your outdoor lighting and reduce light-spread, if possible, in high-quality habitat areas.
- The Xerces Society for Invertebrate Conservation provides excellent resources and general information about firefly conservation and an especially valuable downloadable publication, “Conserving the Jewels of the Night.”
- iNaturalist is a great app and website to post firefly photos (and almost any other nature observations) to help you identify fireflies by comparing your sightings with those of other observers. iNaturalist also provides a field guide to fireflies of the US and Canada and you may be able to use this site to find firefly experts in your area.
- Firefly Watch is a citizen science program of Mass Audubon in which participants of any age commit to observing and reporting firefly sightings from an area of their choice — a nearby park or their own backyard — for 10 minutes a week during firefly season.
- The Fireflyers International Network links biologists and entomologists worldwide who are working on firefly conservation. Resources and links to scientific papers can be found at the Fireflyers International Network website.
Richard J. Dolesh is Editor at Large for Parks & Recreation magazine.