Benthic Macroinvertebrate Sampling
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
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
Volunteers check a kick skein for aquatic "bugs." We're always excited to see what we caught!
Photo: S. Shepherd
Everyone helps pick creek critters from the net.
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!
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Photo: S. Reilly
Photo: S. Shepherd
Inhabitants of the creek are fascinating to people of all ages!
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."
Photo: Lynn Joiner
Field guides help us identify the tough ones.
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.
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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Photo: S. Reilly