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Benthic Macroinvertebrate Sampling

Team of Master Naturalists using a D-net to collect benthic macroinvertebrates in a Powhatan creek

Photo: S. Reilly

JRMN monitors the health of three streams in Powhatan and Goochland Counties by sampling benthic macroinvertebrates. These small creatures that live in the bottom of streams differ in their sensitivity to water pollution, so their presence or absence as well as their numbers is an indicator of stream health. We use a protocol provided by Virginia Save Our Streams, a program of the Izaak Walton League. We record our findings and submit them to a public online database.

Photo: S. Reilly

Jones Creek in Powhatan

Run-off from pesticides and fertilizer, plus sediment from exposed riparian zones, impairs downstream conditions, making the water unfit for aquatic life. The type of invertebrates living on the bottom indicates the overall level of stream health.

Photo: R. Reilly

Team of Master Naturalists using a kick skein to collect benthic macroinvertebrates in a Goochland creek

Volunteers check a kick skein for aquatic "bugs." We're always excited to see what we caught! 

Team of Master Naturalists sorts benthic macroinvertebrates spread out on a stand

Photo: S. Shepherd

Everyone helps pick creek critters from the net.

Various benthic macroinvertebrates collected during sampling

Photos: S. Reilly & R. Reilly

Who knew so many invertebrates live in the stream bed? Pictured in the grid from left to right and top to bottom are a dragonfly, dobsonfly, mayfly, damselfly, stonefly, water penny, fishfly, caddis fly, and a second type of dragonfly. All of these are immature stages of insects that will leave the water to fly as adults!

Master Naturalist examining a benthic macroinvertebrate

Photo: S. Reilly

Master Naturalists and interested visitors observing benthic macroinvertebrates in a pan of water

Photo: S. Shepherd

Inhabitants of the creek are fascinating to people of all ages!

Team of Master Naturalists sorting and counting benthic macroinvertebrates in ice cube trays

Photo: S. Shepherd

Ice cube trays are a handy way to separate and sort small invertebrates. The Virginia Save Our Streams protocol requires that we collect at least 200 "bugs."

Master Naturalists reviewing a field guide to identify benthic macroinvertebrates

Photo: Lynn Joiner

Field guides help us identify the tough ones.

Master Naturalists reviewing data entries following sampling

Photo: S. Shepherd

Metrics developed over many years of research provide a reliable way to calculate stream health based on the relative numbers of invertebrates with different levels of pollution tolerance.

Drone shot of Master Naturalists and visitors at stream monitoring site in Goochland

Photo: S. Shepherd

After all the bugs have been sorted, counted, and identified, they are carefully returned to the stream. . . . Sometimes it's hard for us to say good-by to the underwater world and the amazing creatures that call it home.

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Crayfish seems to wave goodby before being returned to water.

Photo: S. Reilly

The Virginia Master Naturalist program is open to all, regardless of age, color, disability, gender, gender identity, gender expression, national origin, political affiliation, race, religion, sexual orientation, genetic information, veteran status, or any other basis protected by law. An equal opportunity/affirmative action employer.

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