Stoneflies and other macroinvertebrates: A sure sign of water quality at Midewin National Tallgrass Prairie

August 23, 2021

Stonefly under the microscope — A peek at a stonefly under the microscope. Increases in the numbers of stoneflies and other macroinvertebrates in creeks at Midewin National Tallgrass Prairie indicate healthy water quality. USDA Forest Service photo courtesy of Midewin National Tallgrass Prairie

ILLINOIS – Go, stoneflies, go! It is hard to believe something as tiny as a stonefly can tell us so much about the quality of water, but stoneflies and other macroinvertebrates are strong signals of healthy water quality in creeks at Midewin National Tallgrass Prairie.

Year after year, monitors are noticing increases in stoneflies, damselflies, dragonflies, mayflies and more. Volunteers and staff members work in tandem with the Illinois RiverWatch Network to collect water samples.

“The water quality monitoring that is happening at Midewin National Tallgrass Prairie with the Illinois RiverWatch Network is essential to prairie restoration,” said prairie hydrologic technician Rob Lorens.

“Macroinvertebrates are important biological indicators of water quality and ecosystem health. From macroinvertebrates and fish near the pebbles and vegetation at the bottom of creeks to beavers, turtles, birds and other wildlife that depend on water quality, monitoring is the first step to ensure that these species continue to exist on the tallgrass prairie and elsewhere.”

Water quality monitors work directly in the waterways wearing rubber waders pulled high up to their hips or chest. Monitors shuffle their feet to stir up macroinvertebrates and then collect them in water sample containers.

FS scientist looking through a microscope — *Midewin National Tallgrass Prairie volunteer Gail Pyndus studies macroinvertebrates through a microscope. USDA Forest Service photo courtesy of Midewin National Tallgrass Prairie*

Water samples are drawn from nine sites: Grant Creek (two sites); Jackson Creek (two sites); Jordan Creek (one site); and Prairie Creek (four sites).
Later, specimen samples are examined through a microscope by trained observers, which allows volunteers to determine the number and type of macroinvertebrates in the water.

Teams also measure width, velocity, temperature and dissolved oxygen of waterways.

Volunteers with Illinois RiverWatch Network have been collecting valuable water quality information at Midewin National Tallgrass Prairie since 1998.

“This kind of long-term record helps us understand how streams respond to natural and human-caused changes like climate change, land-use alteration or habitat restoration,” said Illinois RiverWatch Director and stream ecologist Danelle Haake.

To learn more about how you can be involved in water quality monitoring, visit www.ngrrec.org/RiverWatch.

A mountain in the background, and a river edged on both sides by forests — An early autumn sun sets gently over Prairie Creek along Boathouse Road at Midewin National Tallgrass Prairie. Increases in recent years in stoneflies and other macroinvertebrates in Prairie Creek and other creeks indicate healthy water quality at Midewin National Tallgrass Prairie. USDA Forest Service photo courtesy of Midewin National Tallgrass Prairie