Extinction on the local scene

Dave Foley (Originally published in Cadillac News)


Our long winter may now finally be ending.  The woods will soon be tinged with green, and the outdoors will come alive again. Birds, animals, insects, and all manner of aquatic organisms, like so many old friends, will fill our neighborhood . But some never return. Crayfish, leeches, mayflies, bullfrogs, June bugs, fireflies - creatures that inhabited the wetlands, woods, and Lake Mitchell by our house a quarter century ago have disappeared completely or are rarely seen. Reading Elizabeth Kolbert's book The Sixth Extinction  helps put this in perspective. While cataclysmic events such as glaciation, volcanic eruptions, asteroid impacts and changes in ocean chemistry have caused mass extinctions in the past, Kolbert notes that, “Right now we are in the midst of the Sixth Extinction, this time caused solely by humanity's transformation of the ecological landscape.” She goes on to recount incidences around the world where man has inadvertently or deliberately caused the decimation of living species at an alarming rate. As I read, I began to think about instances of this phenomena going on literally in my own backyard and the lake beyond our doorstep.   

    The annual hatch of mayflies used to be an event that was both loved and loathed. Loved because the flies were such a great food source for fish and loathed because when swarms of flies rose off the lake surface around the first week of June, homeowners had to deal with thousands of flies stuck in window screens and lying dead on their decks. Walleye fishing tanked.  Our hooked offerings of night crawlers, minnows, and lures went untouched as gamefish gorged on the hatching insects. My journal shows the last big hatch was in 1988. Four years later my notes say. “No mayflies anywhere.” 

There was a time when I would see crayfish darting among the rocks along our lakeshore. On occasion I appropriated a few to use as enticers for smallmouth bass. They're gone now. I haven't seen a a crustacean scooting through the shallows in years.    

    The leech population suffered as well. It used to be that whenever a group of kids were in the lake, invariably one would emerge, often screaming, with a black rubbery leech attached to a leg. We'd grab the box of Morton Salt that we kept on the deck, sprinkle the white grains on the tiny creature and watch as it curled up and let go.  But then the leeches disappeared. I hadn't needed salt box  in decades until last summer. Hearing a squeal, I looked up to see a toddler in tears rushing to his mom, his shin adorned with a small writhing leech. I felt sorry to see the child in in distress but also happy. Maybe this is the first of a next generation of leeches. I sure hope so.  

What happened to the mayflies, crayfish, and leeches? I am afraid we can blame their disappearance on copper sulfate that was sprayed on the lake to treat swimmer's itch. Each year in June a crop duster would fly low over the water dropping blue crystals into the water. At the same time, a boat moved along the shoreline carrying an individual shooting a stream of inky blue liquid into the rocks that lined our shore. These chemical treatments were  supposed to kill the snails that carried the parasite that caused swimmer's itch. The treatments were stopped  in the late 1980s, but the copper, that accumulated  over the years on the lake bottom, likely reached a level that proved toxic to mayflies, leeches, and crayfish.     

      While there seems to be an explanation for the eradication of organisms that once resided in the lake, I can only speculate about what happened to the June bugs, that used to circle our porch light and smack into our living room windows. You didn't have to see them to know they were around. When airborne, their wings created a hum. If we stepped outside we'd find bronze back beetles scattered about on our deck. Not any more. Nowadays sightings are rare in our yard. “Google” with keywords “June bugs and declining numbers” and you'll see mention of pesticides. A chemically treated lawn probably does in the white grubs that become beetles.

Fireflies, that's another insect that is pretty much “MIA.” Seeing the flickering tiny dots of yellow light dancing across our yard and through the woods, to me is the essence of a summer evening. As a kid I remember collecting them in a jar. We called them lightning bugs. Then my brother and I would take them to our bedroom to watch the  little light show as we fell asleep. Once we were asleep, Mom would take them out and release them in the yard. Years later our kids captured fireflies and once they were asleep, I would become the liberator of the lightning bugs. Last summer I saw only a few. I hope there will be some here when my grandchildren come to visit this year.

    In my research, studies I found pointed to the ever expanding number of yard lights as a possible cause of the decline of fireflies. Apparently these insects need darkness so that mates can find each other.   

I'm sure that the creatures I've described aren't the only ones to disappear from our neighborhood. Although I've paid close attention to birds in recent years, I'll bet some species that were here a couple decades ago no longer inhabit the area. The same could be said for insects, trees, and plants. Kolbert indicates that at the current rate of extinction another 15% of the world's species will be gone by 2050. It's a sobering thought to realize what is happening. I would hope we can become better stewards  of our environment.