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Concern over firefly decline yields need for conservation plan in Delaware

Christopher Heckscher
Delaware State University
The Photuris mysticalampas, a species of firefly that is so far, unique to Delaware.

Human interference with natural habitats is leading to the decline of many firefly species; but a species native to Delaware and possibly Maryland seems to be in abundance.

Delaware State University Environmental Science professor Christopher Heckscher discovered the Photuris mysticalampas in 2004.  It inhabits Atlantic White-Cedar swamps and is one of two rare species native to Delaware. Heckscher checks in on how it’s faring in the Nanticoke River floodplain every once in a while.

“I’ve been back there almost every year since 2013 and they’re there," Heckscher said. "They're in good numbers and seem to be doing fine."

But one mystery is they are not in the original spot where Heckscher found them — Prime Hook National Wildlife Refuge.

“Several years later when I returned to the site, I didn’t see them. That doesn’t necessarily mean they weren’t there,” Heckscher said. “I could’ve been too early or too late. It could’ve just been a bad year for that species, but it’s definitely something I do want to follow up on.”

He first stumbled upon the species while doing a biological survey and inventory at Prime Hook. At the time, he couldn’t immediately identify it, and assumed it was a species from southern United States at the northern edge of its range.

Thirteen species of firefly have been declared "greatest conservation need" in DNREC's 2015 Delaware Wildlife Action Plan.

But years later, while surveying the Nanticoke River, Heckscher found the species in abundance and was still unable to identify it. That’s when he realized he was dealing with a new species.

“I’d like to get into other areas to look for this (firefly) and get an idea for how restricted its range is,” Heckscher said. “Does it only occur in Sussex County or is it more widespread?”  

While questions about the mysticalampas' presence in Delaware and Maryland remain, there is some uneasiness about firefly populations, as 13 species have been declared species of greatest conservation need in the 2015 Delaware Wildlife Action Plan. Anthony Gonzon, a biodiversity program manager with Delaware’s Department of Natural Resources and Environmental Control, notes fireflies face many issues, including landscape changes, climate change and sea level rise. These changes reduce food sources or the habitat fireflies need to lay their eggs.

“One of the things we would like to do, certainly, is to monitor them more efficiently,” Gonzon said. “Certainly with the Bethany Beach firefly (the other rare species in Delaware), that’s something we’d like to monitor every couple years or so.”

Though fireflies have been designated as greatest conservation need, nothing is currently being done to save them. Gonzon said DNREC has identified nearly 700 species under this classification, but not all of them receive the same level of priority.

"We look for things that are of the greatest level of imperilment and we try to focus on those first," Gonzon said. "Anything that is federally listed is of the highest priority — Piping Plovers, Red Knots, things like that."

Gonzon said there is also no one on DNREC's staff that works directly with insects.

"We'd like to do more insect surveys," Gonzon said. "It just takes a matter of time to sit down and write projects up and get them funded. Funding often isn't a roadblock per se, because we have state wildlife grants and other grant money we could potentially pursue. A lot of times it comes down to actually having the staff to do the work."

And firefly decline is not just happening in Delaware. It's occurring mostly everywhere where human dominanted landscapes are being built, said University of Delaware entomology and wildlife ecology professor Doug Tallamy.

“Larvae fireflies live in leaf litter, where they feed on worms, so when we rake up every leaf that falls, you’ve destroyed all the habitat for larval fireflies,” Tallamy said. “If you have security lights that blaze all night long, you’ve interrupted the communication ability of the adults.”

Tallamy added in recent years, farming communities have adopted “clean farming techniques,” getting rid of all of the weeds on the side of their fields, replacing it with lawn. This, Tallamy said, is deadly to any species that needs those plants — monarchs, native bees, fireflies and other insects.

“We’re getting rid of the resource base that supports them,” Tallamy said.

A change in human habits is needed to save the fireflies and other insects, Tallamy said. Globally, he said, there is a 45 percent decline in insects.

“We have to realize that the landscapes where we live, where we work, where we play, are important components of local ecosystems,” Tallamy said. “In many places, they are the only components of local ecosystems. We have to recognize that we need ecosystem functions to exist.”

Heckshire said to protect fireflies, these lands need to be undisturbed.

“We need to do a good job in identifying natural areas that have not been disturbed and work towards trying to keep them undisturbed through land acquisitions or conservation easements, which is working with landowners…” Heckshire said.

Surveying firefly populations and understanding where they are abundant could help lead to appropriate conservation management recommendations and decisions, Gonzon said. It all depends on when an opportunity to more keenly manage fireflies comes along.