Caves
In a long, slow process, water seeping through the limestone bedrock that underlies much of Missouri has carved out a vast system of underground springs and caves. Missouri has over 5,500 caves.
Caves are divided into three zones based on light, temperature and humidity. The eastern phoebe and cave cricket prefer cave entrances. Other species, such as little brown bats and pickerel frogs, prefer the "twilight zone," the shadowy region between the sunlit entrance and the deepest recesses of the cave. Species adapted to the zone of total darkness never leave the black sanctuary of the cave, and most, including Ozark cavefish and bristly cave crayfish, have lost eyesight and skin color.
Cave-dependent species have always been rare because their habitat is limited. Protecting the fragile balance of cave environments is critical to the survival of these communities.
Watershed Protection
Mary Lou and Ernie Braswell
Blind Ozark Cavefish
Mary Lou and Ernie Braswell (right) are private landowners in Christian County who help protect the habitat of the endangered Ozark cavefish, a species sensitive to water pollution, watershed disturbance and silt runoff. Many landowners voluntarily protect caves on their property by planting trees around entrances, capping wells and fencing off sensitive areas.
Blind Ozark cavefish navigate cave streams and locate food and mates in total darkness. This ghostly, seldom-seen fish serves as an indicator of clean water.
Cave Management
"Bat-friendly" cave gate
Conservation Department workers replace old cave gates on public land with a more "bat-friendly" design that keeps out intruders but allows bats to fly in and out freely. Precise construction is critical to prevent the bats from abandoning the cave. Since 1996, 13 new gates have been built at the openings to some of the Conservation Department's most important caves. Less than five percent of Missouri's caves are inhabited by endangered bats.
A Tale of Two Bats
Indiana bats
Monitoring a hibernation cave
Both Indiana bats and gray bats are federally endangered species that require caves for hibernation, but over the last 10 years, gray bats have increased while Indiana bat numbers have continued to fall. Gray bats use caves as their maternity wards, but Indiana bats migrate north of the Missouri river and gather beneath loose tree bark to raise their young. Because Indiana bats are exposed to threats in each area, protecting hibernation caves is not enough to halt their decline.
Conservation Department biologists monitor the temperature of endangered bat hibernation caves. Bats do not feed during hibernation. They depend on fat stores to carry them through the winter months.
