The world of aquatic macroinvertebrates is a wild one. These creatures lack a backbone (think insects, snails, and crayfish), are “macro” because they’re big enough to see with the naked eye, and they are definitely worth a closer look!
For starters, there’s the Water Scorpion, a predatory insect named for its long breathing tube that looks like a scorpion’s tail but functions more like a snorkel butt. Whirligig Beetles have eyes that allow them to see above and below the water simultaneously while they swim in dizzying circles. And many familiar flying insects like dragonflies, damselflies, and mayflies begin their lives as aquatic larvae, each with their own fascinating morphology and behaviors.
But as intriguing as these creatures are individually, we can learn even more by considering them in their ecological context. As any angler who has tried to “match the hatch” knows, macroinvertebrates are food for fish and amphibians, plus turtles, birds, bats, and other wildlife living in and around waterways. Many are detritivores, eating dead and decaying matter to keep nutrients cycling through the ecosystem. Moreover, their distribution tells an important story about habitat health. We know that some macroinvertebrates are sensitive to pollution and are only found in clean, oxygen-rich water. The presence of sensitive species in a given waterway indicates good water quality, while their absence may be a sign of trouble. Species that are more tolerant of pollution or poor water quality are found more broadly.
This is where the Marsh and Stream Explorers community science project comes in. Since 2020, Maine Audubon, the Maine Department of Environmental Protection (DEP), and partners have trained volunteers to survey streams and freshwater marshes for aquatic macroinvertebrates. With more than 5,000 streams and rivers in Maine, Marsh and Stream Explorers volunteers help gather much more data statewide in one season than would be possible with only DEP staff. The data the volunteers gather serves as an initial water quality screening tool and allows DEP to make better decisions about where more in-depth assessments are needed. It’s a true win-win: Maine DEP is able to use limited resources wisely and volunteers learn new skills and get out in their local streams and freshwater marshes to discover what macroinvertebrates are there.
On April 22, join us online over Zoom for Marsh and Stream Explorers: A Treasure Hunt to Find Healthy Freshwater Habitats in Maine to hear more about this exciting project from Community Science Manager Mady Eori. Along with sharing past results and future goals for the project, she’ll provide an overview of key macroinvertebrate groups, their ecology, and why protecting them and their habitats are important. This is a great introduction for anyone interested in freshwater ecology or who would like to learn more about the project—no need to get your feet wet!
For those ready to take up a net and volunteer, you can also join us for an in-person training in the field this spring.
On April 25, we’ll be at Fields Pond Audubon Center in the greater Bangor area and Mill Brook Preserve in the greater Portland area.
Here are the May trainings:
May 2: Topsham
May 16: Belgrade
May 30: Gilead
If you’re unable to join us in the field but still want to become a trained volunteer, you can watch previous training webinars, a field survey demonstration video, and find all other materials and resources you need on the Marsh and Stream Explorers webpage.
