Nature Notes: The Hidden Gem of the Sanctuary

Posted on Jul 27, 2023 by Jackie Rath No Comments Yet | Posted in Blog · Featured · Nature Notes

By Jackie Rath, Program Coordinator

Up close with the Hine’s Emerald Dragonfly. Photo by Carol Freeman.

Did you know that one of the most precious species of The Ridges Sanctuary is the Hine’s emerald dragonfly (Somatochlora hineana)? This winged wonder is listed as Federally endangered and its largest populations are found in Door County, particularly in The Ridges Sanctuary and surrounding wetlands. In fact, the Hine’s emerald dragonfly is among the most endangered dragonflies in the United States due to many factors, including groundwater contamination and depletion. Door County populations rely heavily on the critical habitat we have here in Baileys Harbor.

When they became the first (and so far, the only) dragonfly placed on the Federal Endangered Species list in 1995, not much was known about their natural history. Since then, researchers at a variety of state and federal agencies in Illinois and Wisconsin have filled in a lot of the gaps. At the Ridges, field studies of the number and behavior of Hine’s emerald dragonflies, along with obtaining photographic records, have been conducted.

Our mission at The Ridges is to promote positive environmental behaviors through impactful educational experiences, land management and protection, and ecological research. The Ridges continues to ensure the protection of the Hine’s emerald and its surrounding habitat at the Sanctuary by doing just that. One example being the recent purchase of Ridges Inn parcel to protect Hidden Brook, which bisects the Ridges property and is critical habitat for the endangered Hine’s emerald.

Other impactful ongoings include ecological research of habitat/loss of wetlands through citizen science and place-based adult and youth educational programming. Volunteers and staff contribute to Water Action Volunteers stream monitoring regarding stream health and water quality, which directly impacts Hine’s habitat. Youth programming (i.e., Ridges Forest School, Tiny Trekkers, and Backpack Adventure Camp) incorporates learning about and monitoring the habitats of this species. Where and why does this species live here? Why do they like our swales? Why is it a species of concern? How can we protect this species and its habitat?

The Ridges and surrounding landscapes have been recognized as the most biologically diverse area in the State by the Wisconsin Department of Natural Resources. With a distinctive topography of low, sandy ridges, alternating with wetland areas of swales, it is no wonder that this species has found a home here at The Ridges.

Scientific sketch by Jackie Rath.

The life cycle of a Hine’s emerald dragonfly is similar to most dragonflies in that it is comprised of the following stages: aquatic egg, aquatic larva, and a terrestrial/aerial adult. Dragonflies live in wetland habitats. The Hine’s play a crucial role in maintaining the health of our swales, and their presence is essential for their success. Dragonflies are important to wetland ecosystems because they act as an indicator of wetland health. A canary in the coal mine, if you will. If you see a lot of dragonflies in a wetland habitat, it’s presumably very healthy.

After an egg is hatched, the Hine’s spends four to five years in its larval stage. Young Hine’s nymphs live in shallow, cool, slow-moving water (i.e., Swales!). Throughout this time period, the Hine’s survival is dependent on sustained groundwater quality and quantity that is fed through karst bedrock into coastal wetland habitat. There are 12 areas on the peninsula that have been designated as critical habitats, but there are also additional sites where Hine’s have been identified. Hine’s emerald dragonfly larvae survive dry periods and winter months with some risk in tow – by hiding in crayfish burrows, one of their main predators.

Dragonfly larvae at various stages of growth. (USFWS)

If they make it to the completion of larval development, the adult dragonflies emerge and take to the skies in mid to late June. You’ll find many of these dragonflies zipping around in the hot summer months while they mate and carefully lay eggs for the next generation of the species.

These dragonflies are about 2.5 inches long and have bright emerald green eyes. According to USFWS, dragonflies and damselflies are characterized by two pairs of large membranous wings; large compound eyes; short, bristle-like antennae; chewing mouth parts; slender, elongated abdomens, and male secondary reproductive organs.

While we could get into the technical scientific jargon of its description, as a Ridges Educator who works with youth programming in the Sanctuary, I wanted to hear a different perspective on this gem of a species. On a recent stream day exploration, Backpack Adventure campers found dragonfly larvae and immediately had questions. I asked some of our campers, who witness this species firsthand at all variations of its life cycle, how they see and would describe the Hine’s emerald:

Dragonfly larvae found by Ridges campers.

Campers observe one of the Hine’s primary predators, a crayfish.

“It has long wings. Looks more like a helicopter with a bigger end on one side and skinny on the other side.”

“I really like its eyes. They are very pretty and very colorful but kind of weird and shiny. I feel bad for endangered animals, though.”

July and August present the best opportunities to observe these dragonflies up close and personal, especially along the “dragonfly run” aka Sandy Swale. We recommend visiting on a hot and sunny day for the best chances of seeing these majestic beauties.

Dr. Dan Soluk gently holds a female Hine’s emerald dragonfly between his fingers. Photo by Emily Mills/TNC.

To learn more about this endangered species and the research conducted by Dr. Dan Soluk in Door County, check out the sources below, including a great article by Craig Sterrett, published by The Peninsula Pulse.