Pearls of the Gasconade
explains. "The gravel comes down and fills in areas where there is diverse habitat. Where you had a mix of riffles, pools and holes it becomes homogeneous. The species that depend on those niches get pushed out." Specialized niche species--those that account for so much of Missouri's natural diversity--lose out to the generalists, the Asian clams and others better able to adapt.
Bruenderman and Faiman again head upstream in their 18-foot boat. Faiman opens the throttle on the 45-horsepower motor, causing the boat to buck slightly against the swift current. He eases the boat up to a long gravel bar. Bruenderman jumps out and disappears into a thick stand of sycamores and willows. Debris stuck in low-lying tree forks shows where high water has come and gone. It's a good place to find mussel shells.
In no time, Bruenderman cradles a dozen or so in her hands. "If we find shells, we know that now or at some point the site supported that species," she says. "We can also use it as an indicator of whether that site would be a good candidate for reestablishing a mussel community." Middens, places where muskrats or raccoons dined and left behind piles of shells, can serve the same purpose. Today, however, they often contain more Asian clams than native species.
Both biologists have hopes today of finding one of the state's rarer mussels--the snuffbox. It's part of the same genus that includes Curtis' pearlymussel, a species that mussel experts now concede is likely extinct. That makes the snuffbox the last of its genus in Missouri. The swift water of this riffle would be a good spot to find them, but the odds are against it. They have never been found in the Gasconade. Old males have turned up in the Meramec, but there are few signs the species is reproducing there.
Faiman returns to the water as Bruenderman searches the bank for more shells. Moments later he is once again doing the crawdad crawl along the bottom, his hands probing the streambed. He splashes to his feet and eagerly turns a mussel over and over in his hands. "I just found a scaleshell," he reports. It's a significant discovery. The U.S. Fish and Wildlife Service is considering the rare scaleshell for protection under the Endangered Species Act.
The scaleshell has declined across its range, leaving Missouri as its last stronghold. "We have the best population of them left in the country in the Meramec," Bruenderman explains. "We're seeing them here in the Gasconade as well." She comes close for a look as Faiman pulls out calipers to measure the shell and determine its age. Minutes later he gingerly returns the mussel to its watery home. Earlier in the day Faiman also released an elephantear mussel he discovered.
It's near the end of another day on the Gasconade, and Faiman eases the boat downriver. To the biologists' trained eyes it's been a day of sharp contrasts. They documented degraded stream habitat, but they also found positive signs in the number of species they turned up. They also found sizable pockets of stable habitat, places where mussels could thrive. And they verified that the Gasconade still sustains two of the state's rare mussels.
WHAT can you do?
- Intensive urban development increases runoff and water velocity, which worsens erosion and changes stream channels. Get involved with your local zoning board and city council to protect or improve stream quality.
- Avoid or minimize your use of lawn chemicals--fertilizers, herbicides and pesticides. If you use them, follow the directions for mixing and application. Remember, runoff pollutes local streams and groundwater.
- Control erosion from construction sites with silt fences and silt catch basins.
- Fence livestock at least 100 feet from the stream on each bank. Overgrazing kills vegetation that holds the soil in place and filters runoff water.
- If you're farming bottomland or planning watershed development, allow for a forested buffer along the streams. Look into the growing number of economicaly feasible agricultural alteratives, such as growing ginseng or walnut trees.