Aquatic Invertebrate Monitoring at Ozark National Scenic Riverways

Late morning on a river in the Ozarks.
River at Ozark National Scenic Riverways.


Ozark National Scenic Riverways is a magical place where more than 425 springs flow from the ground. The largest, Big Spring, gushes enough water to fill an Olympic-sized swimming pool in about two minutes. The springs are at risk of being polluted because contaminants flow from the surface through the springs. Land practices, such as clear cutting, are the biggest threat to streams and springs in the Ozark Highlands. Since 2007, NPS scientists have monitored several large springs in the park. For example, scientists monitor aquatic invertebrates in the springs to assess water quality. Invertebrates include insect larvae, worms, and crayfish. Invertebrates may live in the spring for several months or more. This exposes them to changing water quality conditions over time. Some species can live in poor water quality, while others need pristine conditions. Therefore, the aquatic invertebrate community is the “canary in the coal mine” for water quality in these springs.
Mean SCI and standard errors (n=3) for mainstem river sampling sites at Ozark National Scenic Riverways.
Mean SCI and standard errors (n=3) for mainstem river sampling sites at Ozark National Scenic Riverways. ≥16= Fully biologically supportive, 10-14=partially biologically supportive, 4-8=not biologically supportive.


Scientists use established methods to monitor aquatic insects and water quality. Monitoring invertebrate diversity tells us how streams change over time. We find out what species are there and their tolerance level to pollution and disturbances. This helps us estimate water quality conditions in the spring in the previous few months. Traditional water quality monitoring often does not indicate all disturbances that pose a great threat to the springs.
More than 100 different types of invertebrates have been found in the springs and most of them are environmentally sensitive. Currently, the springs are high quality environments. More monitoring may allow insight into trends occurring in the springs.
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Data in this report were collected and analyzed using methods based on established, peer-reviewed protocols and were analyzed and interpreted within the guidelines of the protocols.

Last updated: April 4, 2018