Most Nebraskans would be surprised to learn there is a beetle named after the city of Lincoln and that it is one of the rarest insects in the world, with less than 500 found yearly.
Their habitat is equally unique, and soon, it might not exist.
The Salt Creek Tiger Beetle (scientifically Cicindela nevadica lincolniana) is a critically endangered subspecies of Tiger Beetle native only to saline wetlands in Lancaster and Saunders counties in Nebraska. Stephen Spomer, a retired research entomologist for the University of Nebraska-Lincoln, said the beetles became separated from other tiger beetles when the salt marshes formed.
“It was supposedly dropped off here some time in one of the glaciation periods around 10,000 years ago,” Spomer said. “It’s very isolated.”
Shawn Dunn, a zoologist with Nebraska Game and Parks, as well as Spomer’s co-author in the only long-term study on the Salt Creek Tiger Beetle, said the beetles are an indicator species or a species that is used to gauge the health of specific ecosystems. He said this is because while other species take up residence in Nebraska’s saline wetlands, the Salt Creek Tiger Beetle cannot live anywhere else.
“They’re actually a really good indicator of high-quality saline wetlands,” Dunn said. “And so having them around lets us know how these wetlands are doing.”
Spomer said this is due to the Salt Creek Tiger Beetle’s isolation from other Nebraska Tiger Beetles. He said the isolated beetles have evolved to only be able to live in saline wetland environments, so the population of the beetles is determined mostly by the carrying capacity of suitable saline wetlands.
The wetlands are different from others in the state because they have higher concentrations of salt. Dunn said settlers founded Lincoln around Salt Creek due to the abundance of the mineral in the area. In states such as Nebraska, saline wetlands normally should not exist.
“Within the inland parts of most areas, it’s pretty rare to find saline wetlands. You typically find those closer to saline water sources, like the ocean is the most common one,” Dunn said. “To have these inland in a heavily landlocked area like the Great Plains is really unique.”
Spomer had been conducting yearly counts of the Salt Creek Tiger Beetle since 1991, and while he said the beetles are avoiding a decline, the population is currently not increasing.
Development of the City of Lincoln used to be a major driver behind the beetles’ decline, though Spomer said their classification as an endangered species has prevented a majority of development and has kept pesticides out of the wetlands.
Spomer and Dunn both indicated the new threat facing the Salt Creek Tiger Beetle is climate change. Dunn pointed to rainfall patterns and shifting as the climate changes, causing dry summers interrupted by severe intermittent rainfall.
The result is normally unfortunate for the beetles Spomer said, as the wetlands become invaded by grasses and cattails. He said the beetles, while no longer in decline, are losing suitable habitats fast.
“They’re kind of maintaining a population, but I think there needs to be more sites,” Spomer said.
According to Spomer, only about 10% of the original range of saline wetlands where the Salt Creek Tiger Beetle lives remains, and according to the recovery plan put forward by the U.S. Fish and Wildlife Service, they are being seen in fewer sites. His main concern is finding and increasing the available habitat for the beetle to the point where growth can occur.
Spomer said if it weren’t for joint conservation efforts by several organizations, including the Game and Parks Commission, the Henry Doorly Zoo, the Saline Wetland Conservation Partnership and UNL, the wetlands could disappear forever. He said efforts have persisted since the early 2000s, once the beetles were classified as endangered. These efforts have included purchasing saline wetlands for conservation, as well as an extensive monitoring project.
“It’s a very unique type of habitat. It’s considered an endangered habitat because of how isolated it is in eastern Nebraska,” Spomer said.
Zhenghong Tang, a professor at UNL and director of the Community and Regional Planning Program at UNL, was involved with the monitoring project.
The collaboration involved the installation of sensors in the saline wetlands, giving researchers up-to-date information on the health of the wetlands. Alongside the college on this project was the Nebraska Saline Wetland Conservation Partnership, which includes the City of Lincoln, Lancaster County, the Lower Platte South Natural Resource District and Nebraska Game and Parks.
Tang said the sensors provide researchers with data on the soil and water in the saline wetlands every 15 seconds.
“The sensors provide real-time readings of the soil salinity level and the water salinity levels,” Tang said. “That can provide scientific evidence for wildlife managers to implement or adopt more scientifically based restoration practices.”
Spomer said the Saline Wetland Conservation Partnership, which purchases suitable wetlands to preserve them, is a major player working to increase the availability of habitat for the Salt Creek Tiger Beetle.
Several wetland areas reserved by the SWCP for conservation and preservation are open to the public, including Frank Shoemaker Marsh, Arbor Lake and Marsh Wren, all located within a 10-minute drive north of Lincoln.
He said their effort to purchase and maintain wetlands is necessary to see the population of the Salt Creek Tiger Beetle grow.
“Without more sites, I think the numbers are going to stay about where they are now,” Spomer said. “I don’t see the numbers increasing until there’s more efforts to increase the habitat.”
More than just providing available habitat, Spomer said reintroduction efforts are important to see the beetles resurge. He said sites that have seen a complete loss of Salt Creek Tiger Beetle populations can still ideally see the beetles reintroduced. The Henry Doorly Zoo and the Lincoln Children’s Zoo are involved in the effort.
While hopeful, Spomer said it is very difficult to know if reintroduction efforts are succeeding. He said placing larvae in the saline wetland habitats is easy, but keeping track of them is more difficult. Their burrowing habits make them hard to track, and rainfall tends to disturb sites marked by conservationists.
“We’ve used flags, we’ve used golf tees, all kinds of things,” Spomer said. “They will close their burrows up.”
Despite the dismal picture, Spomer is not giving up on the Salt Creek Tiger Beetle and said Lincolnites should not either.
“The Salt Creek Tiger Beetle has Lincoln in its name,” Spomer said. “It’s named after the city of Lincoln because it’s the only place it’s found.”
Aside from indicating the health of Nebraska’s saline wetlands, Spomer said the Salt Creek Tiger Beetle population is important to local insect populations. As predators, they are helpful for balancing out populations of other insects in their environment.
Dunn and Spomer both said the only way to preserve the Salt Creek Tiger Beetle is to preserve Lancaster’s unique saline wetlands. This is not only important for protecting the beetles, either. He said the marshes are home to a myriad of plants and animals.
“We’ve got unique herbs out there; we’ve got birds that come in and use the wetlands as part of their migratory stopover. Pheasants and deer use the areas, too,” Dunn said. “There’s a whole host of species that actually use the saline wetlands. The Salt Creek Tiger Beetle is just one of those species that helps us have a good indication of how high quality those areas may or may not be.”
Dunn said more than just being a unique habitat, the saline wetlands are an integral part of Lincoln.
“Having the saline wetlands close to a city close to Lincoln, is really, really fantastic. I mean, we’ve got such a diverse group of species so close to the city that people can get out and go see,” Dunn said. “That’s really unique.”
Dunn said people should take an opportunity to see them, if possible. He said the biggest way to promote conservation efforts is to see the area firsthand.
“I think just getting people out there really helps everyone understand what we’re trying to do,” Dunn said. “Once you get out there and experience the diversity there, and you see all the plants, you see all the birds, see the variety of insects, you really understand what we’re trying to do, and you become interested in it.”
Spomer said the Salt Creek Tiger Beetle is important, but they are part of a larger issue.
“There’s a bigger picture, and that’s the whole salt marsh,” Spomer said.
As two long-standing aspects of the city sit at risk, Dunn said he is hopeful of current efforts being taken and hopes to see more saline wetlands protected.
“They really are tied together,” Dunn said. “What happens to one is going to affect the other one.”