to make sure that healthy waters benefits us where we live and where we go to enjoy the outdoors.”
“Canaries” For Healthy Waters
Aquatic threatened and endangered species are often the equivalents of “canaries in the coal mine.” They are indicators of healthy waters—both above and below ground. Working to conserve these endangered species generally means improving
water quality, which ultimately benefits other aquatic species as well. It also ensures healthy waters for the people who depend on it for drinking water and other uses.
One such species, the Ozark hellbender, could be readily found in many of Missouri’s clear cold-water streams until the 1980s. But the populations of these long-lived, large aquatic salamanders have declined significantly due to habitat degradation, poor water quality and other factors. Habitat restoration and population reintroductions are attempting to reverse this decline. Hellbenders depend on crayfish for their main diet, so the loss of the species could trigger a shift in the aquatic food web. Poor water quality may also result in the decline of other cold-water stream species.
Mussels are another water quality canary in the coalmine. They feed by filtering water through their gills—often purifying the water in the process. They are indiscriminate filterers. What they don’t actually consume is released back into the water, becoming food for small invertebrates. Mussels are not tolerant of elevated pollution levels, so a drop in numbers can signal water quality issues that may soon affect other aquatic species as well.
Small headwater dams, road crossings and diminished flows reduce the continuity of streams and the usable habitat for fish. The Topeka shiner, a minnow that once occurred throughout prairies in the Missouri River watershed, is now endangered and found only in a few small, isolated headwater streams. As prairies have experienced disruptions in flow and stream continuity, drought and sedimentation have become more intense. The lack of adequate habitat for Topeka shiners is similar to a lack of air for the canary in the mine.
Many aquatic canaries in our underground streams and caves are much harder to see and understand. The Tumbling Creek cavesnail is a tiny snail found in only one cave system in the world—in Taney County. In the 1990s, surveys showed this cavesnail was in decline. A decade ago, only 30 were found in the entire cave, probably due to poor land management and leaky septic systems in the watershed above the cave. Private landowners have reduced erosion and repaired septic systems, which have helped improve conditions for this species.
A watershed approach to preserving a healthy underground habitat for this tiny snail invigorated the local community and school to work toward improving water quality above and below ground. This ultimately benefits the community, their neighbors downstream and the lowly cavesnail.
If an aquatic species is declining due to poor water quality or lack of water, it’s important for us to take notice. They could be our canary in the mine, warning us to improve our streams—otherwise, our community’s healthy waters may soon be at risk, too.