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Beadle
Isn’t there concern the mud snails may out compete native macroinvertebrates?

Farnheid
Yes, in 2003, the mud snails made up between 25 to 50 percent of the macroinvertebrates found in the Madison River. In the areas occupied by mud snails, there were fewer native mayflies, stoneflies, and caddisflies. Our data also indicated the mud snails were abundant in the Firehole River downstream of the thermal additions, but almost nonexistent in the upstream portion.

Maya
Is this because the snails don’t like cold water?

Farnheid
Maybe, but it isn’t the only reason. Research has also shown that New Zealand mud snails can live in a wide range of temperatures. Their numbers and distribution may be limited more by changes in the river’s water chemistry. Also algae, a major food source for the mud snails, are much more abundant in the warmer parts of the Firehole, as you observed earlier, Ms. Crowbes.


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Cast of characters - Maya Crowbes, Dr. A Beadle, Gray Fischer, Viola DeRama
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Q: Why are there more New Zealand mud snails in the warmer parts of the river?

GLOSSARY: out compete—to compete against in a manner that exceeds and may overpower