A Winged Jewel Gets a Leg Up
By Jennifer Linforth
Division of Program and Partnership Support
A Hine's emerald dragonfly (U.S. Fish and Wildlife Service photo by Paul Burton)
To make a big impact on a small species, you need thousands of cups. At least this may be true for the Hine's emerald dragonfly (Somatochlora hineana).
Rearing Hine's larvae is no small undertaking, but it has been done successfully at the University of South Dakota, with support from the U.S. Fish and Wildlife Service's (Service) Chicago Field Office.
Endangered since 1995, the Hine's emerald dragonfly is the only species of dragonfly to have federal protection. This species is the proverbial "canary in a coal mine" when it comes to detecting ground water stability in the region. The dragonfly's recent decline correlates with drought events and decreased ground water recharge, which could impact people too.
The species breeds in calcareous, spring-fed marshes and sedge meadows over bedrock. Eggs are laid in shallow water and the aquatic larvae hatch the following spring, living three to five years before shedding their skin one final time and emerging as adults. The loss of the species unique habitat from mining and other development activities has the Hine's fighting an uphill battle for survival. With an estimated population of 200 adults left in the Chicago area, preserving this emerald-eyed beauty has reached a serious turning point. The Service is depending on research to preserve, protect, and improve the status of the species and its habitat.
And then came the cups...
Headed by Dr. Daniel Soluk, Associate Professor of Biology at the University of South Dakota, the goal of the Hine's captive rearing program is clear: to release dragonflies that are ready to emerge as adults into existing and restored habitat to augment the Illinois population of the dragonfly so that it can recover to a healthy and sustainable size.
Eggs are collected from gravid, or fertile, females in the field and are then incubated in a lab. Once the new hatchlings emerge, they are transferred to individual cups, where they are fed and kept at various temperatures and photoperiods to mimic their natural habitat conditions. The larvae remain in the cups for approximately five years until they are big enough to be released into the wild and ultimately emerge as adult dragonflies. The program successfully reared 1,643 larvae in 2011 and 2,500 in 2012. After many dedicated but tedious hours in the lab, biologists are pleased with the progress that has been made to develop methods with high success rates to rear the species in captivity.
According to Kris Lah, endangered species biologist in the Service's Chicago Field Office, a program that would restore the Illinois population may require a couple hundred adults per year to be introduced into the population, so a more efficient method is needed to rear the larvae.
"We can really have a positive impact on the species, but we need to establish meaningful partnerships to share our individual expertise and pool our resources. Besides, we don't want to put all our eggs, or larvae, in one basket" said Kris.
The answer may include cross program cooperation between the Chicago Ecological Services Field Office and the Genoa National Fish Hatchery in Wisconsin, The Forest Preserve District of DuPage County, in Illinois, may expand its ongoing partnership with the Service and University of South Dakota, by adapting existing facilities for Hine's captive rearing.
The Chicago Office and University of South Dakota are developing plans and working on identifying potential funding sources.
Once more progress is made on rearing the Hine's emerald dragonfly in captivity; partnerships may restore the species in the wild and move it closer toward recovery.