Every summer, when fireflies begin to make their dazzling evening appearances, locals and visitors alike sit in rapt wonder to take it all in. The light shows of these insects are arguably among the most magical sights in the natural world, enchanting viewers of all ages.
With such a devoted following, it’s perhaps unsurprising that changes in perceived abundance do not escape notice. Over the years, anecdotal reports of decline have grown as people reflect on the brilliant abundances of years past and wonder if these shows are dwindling. Are fireflies declining? Or do we just spend less time outside on summer evenings, caught up instead in our digital worlds?
Overlooked no longer, conservation assessments suggest one third of firefly species at risk
Researchers have been asking some of these same questions. While there are no systematic monitoring programs in place to assess the health of firefly populations in North America, experts agree that some populations are blinking out. Yet until very recently the status of the US and Canadian firefly fauna was largely unknown.
In 2020, Xerces joined with the Albuquerque BioPark and members of the IUCN Firefly Specialist Group to assess the status of 132 species and subspecies of fireflies – about 77% of the known firefly fauna at the time. (Since then, 4 additional species have been described.) Using the categories and criteria of the IUCN Red List, a global authority on species conservation statuses, they found that about a third of these species seemed to be doing just fine.
However, 14% of species were categorized as threatened with extinction, primarily due to habitat loss and degradation, light pollution, and impacts from climate change. Notably, over half the species assessed were considered data deficient, meaning insufficient data were available to assign a risk category. The group’s study, published in the journal PLOS ONE last November, furthermore concluded that up to a third of firefly species assessed may be at risk of extinction, if one assumes that the data deficient species follow a similar risk category breakdown as species with sufficient data.
A Southwest spring firefly (Bicellonycha wickershamorum) rests on a rush at twilight (left). This Arizona endemic is categorized as Red List Vulnerable and is threatened by climate change and habitat loss and degradation as a result of cattle grazing and modification for agriculture and pasturing (right) (Photos: c. Scott Cylwik).
Xerces provides first U.S. firefly conservation guide for wildlife agencies
Taken together, these assessments and the PLOS ONE paper highlight a clear need for expanded surveys, research, and conservation efforts for these charismatic beetles. State, provincial, and local wildlife agencies have a particularly important role to play in coordinating firefly conservation. To that end, Xerces is excited to announce the release of a new publication to help agencies respond, State of the Fireflies of the US and Canada: Distribution, Threats, and Conservation Recommendations.
Restricted to the intertidal zone of salt marshes, mudflats, and mangroves in coastal areas of Florida and the Bahamas (left), the Florida intertidal firefly (Micronaspis floridana; right) is categorized as Red List Endangered. The biggest threats to its persistence are loss and degradation of habitat due to coastal development, light pollution, agricultural activities, and pesticides. Increased severity and frequency of storms may also pose a threat. Several populations in Florida now appear to be locally extinct. Photos: Kelly Verdeck Flickr (left), © Drew Fulton (right).
Compiled by authors at Xerces, the Albuquerque BioPark, and the IUCN Firefly Specialist Group, the guide provides a clear snapshot of the current state of our knowledge of fireflies in the US and Canada. It addresses key questions that agencies face to plan effective firefly conservation efforts and includes information regarding:
- A summary of threats affecting fireflies in the US and Canada
- Maps of species richness, distributions, and threatened statuses
- Species profiles for all 20 fireflies of conservation concern
- A species checklist of all the fireflies in the US and Canada
- A list of species of conservation concern by state and province
- Research recommendations
- Recommended conservation actions for land managers, researchers, and public audiences
Although this report is written with state and provincial wildlife agencies in mind, it can be useful for anyone with an interest in firefly conservation. It is our hope that these findings and the recommendations within will spur firefly conservation and protect one of nature’s most dazzling displays for future generations.
This report would not be possible without the contributions of numerous researchers, taxonomists, community scientists, and others whose data and studies form its foundation. We are particularly grateful to Lynn Faust, Joseph Cicero, Christopher Heckscher, Ben Pfeiffer, and Cisteil Pérez Hernández, as well as the many photographers whose photos illustrate this blog and the report. Funding for this report was provided by the Samuel Freeman Charitable Trust, the Edward Gorey Charitable Trust, the New-Land Foundation, Morningstar Foundation, the BAND Foundation, and Xerces Society members.