i found our only endangered dragonfly in a driveway
the lake cabin we visit every year sits on an imperiled ecosystem and i only just realized it
last month, i found the usa’s only endangered dragonfly species hanging around a driveway.
well, it wasn’t some paved suburban driveway—it was by the lake cabin on michigan’s bois blanc island that my in-laws rent every year. i’ve found lots of cool stuff there, but it wasn’t until i found the dragonfly that i realized there was something truly unique about the habitat. in fact, ecologists give the coastal fen habitat surrounding the cabin a g1g2 ranking, critically imperiled or imperiled.
bois blanc island, “boblo,” is a forested island half the size of brooklyn in the straits of mackinac with a year-round population of 100. we started visiting in september of 2020 so we could see britt’s parents someplace where we’d spend the time mostly outside. they chose the island because it sits exactly halfway between their home in minnesota and our home in nyc, and because it reminded them of the places they’d visit while britt was growing up. i spend the time photographing things i find outside and eating ice cream in a hammock while britt looks for interesting rocks.
on our first visit, i immediately noted the alien-looking habitat around the ferry dock on the island’s south shore. dusty limestone cobble beaches give way to a dense stunted forest of mostly northern white-cedar—a boreal tree more famous for lining suburban yards. as you trace the coast counterclockwise, you pass through maple-dominated deciduous forest and then back to cedars, which thin out into a savanna of conifers interspersed with grassy, wildflower-filled wetland. that’s where you pull into the cabin’s driveway.
while an experienced ecologist might have recognized the habitat, i built up my understanding piecemeal over the course of our annual, week-long visits. in 2020, i recognized that some of the habitats looked similar to bogs i’d visited in upstate new york. in 2021, i mainly looked at moths, finding lots of conifer and wetland-associated ones. in 2022, i noticed that the most common plant around our cabin was a rare iris endemic to the great lakes. in 2023, my brother-in-law, his master gardener partner, and i trekked around the area, finding carnivorous plants like sundews and pitcher plants, two species of orchids, and ericaceous plants like wild rosemary and bog cranberry, where ericaceae is a family of plants famous for growing on infertile soil. and this year, i learned at a q+a with the michigan department of natural resources that a quarter of the island was preserved to protect the massasuaga rattlesnake, which i then saw for the first time (cw - dead animal).
and then came the dragonfly. on the last day of our 2024 visit, i returned to the cabin after a morning birding to photograph the dragonflies that gather at midday in the clearing created by the driveway. a dark dragonfly caught my eye—it looked like an emerald, a family of dragonflies that are famous for their bright green eyes. i followed it until it landed, and noticed it had bold yellow stripes on its thorax and clasp-shaped genitalia—the unique shape of dragonfly genitalia act like lock-and-key systems and can therefore be diagnostic for identifying species. i compared my photos to others online and found only one species matching the combination of features: the hine’s emerald, the only endangered dragonfly in the usa. other inaturalist users quickly confirmed my suspicions.
i started googling. ohio state university professors c.h. kennedy and james hine took the species’ first specimens from a dredged channel of ohio’s little miami river in 1929. they sent the insects to edward bruce williamson, curator of dragonflies and damselflies at the university of michigan museum of zoology. he declared the insect a new species in 1931, noting its unique genitalia and bright thorax stripes, as i had. he named it for professor hine, who died in 1930.
today, the dragonfly has a population of around 30,000, most of them in wisconsin’s door county, with other populations in ontario, illinois, missouri, and michigan. it seems to have been extirpated from ohio, indiana, and alabama. while the iucn lists it as least concern, the u.s. government put it on the federal endangered species list in 1995.
as i read on, i learned that the hine’s emerald is picky about its habitat. it prefers calcareous wetlands, those with lots of calcium carbonate in the soil, with nearby open woods. it also requires crayfish burrows, since hine’s emeralds spend their larval stage in wet crayfish burrows to take shelter during the drier parts of the year.
huh. “calcareous wetlands.” i thought back to the limestone cobble on boblo’s shore—limestone is a rock made from calcium carbonate. i typed something into google like ”calcareous fen bois blanc island,” and one of the first results was a pdf titled “coastal fen” from the michigan natural features inventory.
i opened it up and read. “coastal fen is a sedge- and rush-dominated lacustrine [lake-associated] wetland that occurs on calcareous substrates along Lake Huron and Lake Michigan north of the climatic tension zone.“ “coastal fens are concentrated in the Mackinac straits area of both the Upper Peninsula and Lower Peninsula.” “coastal fens frequently occur within large shoreline complexes that may include great lakes marsh, limestone cobble shore, wooded dune and swale complex, rich conifer swamp, and northern fen. the surrounding uplands are typically dominated by mesic northern forest and boreal forest and can contain a significant component of northern white-cedar.”
huh. they were describing where i was standing. and they said it was listed as g1/g2, meaning imperiled globally with less than 20 occurrences in the world, perhaps critically imperiled. even the threats were familiar to me—invasive species, human development, and habitat destruction from off-road vehicles, among the most common complaints by residents at that dnr q+a.
i already knew that the island had a lot of cool stuff, but it was like i’d found a bunch of cardboard cutouts, not realizing that they were puzzle pieces. finding the hine’s emerald, and in turn finding a name for the habitat surrounding our cabin, was the first time i realized that my sightings fit together to form a truly unique ecological story.
that’s the thing about communities; while they might have rare, localized species, what makes them a community is the assemblage of interacting species, including the common ones. take most of the species from my coastal fen and you can probably find them in a variety of habitats. but the plants, the animals that rely on them, and the unique combination of geology and location all together form the coastal fen community.
plus, those rare species that do inhabit the community rely on the unique assemblage in order to survive. my hine’s emerald, for example, needs calcareous wetlands with crayfish burrows and nearby forest. the pdf listed a few snail species that seem to be unique to the coastal fen, targets to find on my next visit.
after realizing that i’d been stumbling around an imperiled ecological community all this time, i thought about other places i’d visited where the assemblage of species, rather than the individual species, make it special. nyc’s staten island, for example, has patches of serpentine soil that stunt the growth of common plants and support uncommon ones like the green comet milkweed. these ares are also in peril—from development, invasive species, trash dumping, and fire suppression. you certainly have patches of habitats like these near your own haunts—wetlands, copses, and oases that break up the broader habitat whose specifics make them unique enough that your state has documented them as a threatened community.
clearly it wasn’t easy for me to figure out that the area around our cabin was unique—it took years of exploring and documenting. but it encouraged me to not just think about the individual species that inhabit wild spaces, but to dig deeper into their backstories and think about them in the broader context to see what overarching story they tell. and now i have some rare snails to find.
postscript
it may be the slowest time of the year for birds, but it’s the best time of year for everything else—dragonflies, butterflies, plants, eating ice cream, etc. join me on two upcoming nature walks where we’ll look at whatever we can find:
i’ll be leading a bird walk on july 12 from 5:30-7pm at riverside park, meet at the 120th street and riverside drive entrance. no registration required.
i’ll be co-leading a nature walk on july 13 from 12:15-2pm on governors island, plan to take the ferry departing Manhattan at 12pm and head to liggett terrace when you arrive. please register if you decide to join.
in more personal news, i’m moving! just a few blocks away. the habitat surrounding the apartment isn’t quite as good, but green-wood cemetery is basically across the street, so i’m exited about that.
finally: no naturalist’s trip to michigan would be complete without a visit to the state’s stunted jack pine habitat. this year, we visited a younger stand of trees which had different birds like upland sandpipers and brewer’s blackbirds. but this male kirtland’s warbler stole the show, and was singing right next to the road.