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Special Habitats-Caves

© Renie Burghardt

When I moved to the Missouri Ozarks, I first heard the term, "karst topography." What exactly did that mean, I wondered? It seems that a terrain that is based on a layer of soluble bedrock is known as karst. Most often, this bedrock is made up of carbonate rocks. In the Ozarks, this karst forms on limestones and dolomites, both soluble rocks.

The karst of the Missouri Ozarks is characterized by well eroded rolling hills, deep hollows, springs, caves, sinkholes, losing streams, natural bridges, and tunnels. In other words, a perfect area for caves. In fact, Missouri, Kentucky, and Tennesee have the distinction of having the most caves of all the 50 states. Missouri has 5600 documented caves, and many that are still undocumented.

Caves, air filled underground voids, were sculpted by groundwater millions of years ago. They are a dark, bleak habitat, with peculiar inhabitants.

What kinds of creatures live in caves? A surprisingly large diversity of animals both aquatic and terrestrial spends their lives in caves, if not all the time, part of the time. The temperature in caves is a fairly constant 55-58 degrees Fahrenheit. The entrance to the cave is called the entrance zone. Birds often use this area of the cave. They use the mouth of the cave as protection from the weather, and some birds like vultures, sometimes raise their chicks there.

Snakes also use the entrance to the cave, especially in hot summer months. The cooler air helps a snake's body temperature, but they don't usually venture farther into the cave, for there is little food there. Salamanders can also be found in the entrance area, but they also mostly live on the outside.

The leaf litter that blows into caves, may house small millipedes, centipedes, terrestrial isopods, terrestrial snails, earthworms and various insects. Flies and mosquitoes move into the deeper parts of the cave during the winter.

As you get deeper into the cave, where there is much less light, fewer animals can be found. Bedrock fossils such as coral, sea lilies and brachiopods are present on the walls of the caves. These fossils were once inhabitants of oceans. The animals died and fell to the ocean floor, millions of years ago, eventually becoming a part of the limestone or dolomite bedrock in the cave. Black bear's often hibernate in caves.

Of course, bats live in caves. But not all bats. Only certain bats use the cave exclusively, either roosting singly, or in dense clusters with several hundred bats per square foot of the cluster. Some bat species live in caves only during the summer, some during the winter. But some live in caves all year. Bat droppings, called guano piles, are a nutrient source for bacteria, fungi and some small animals in the caves.

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