Caves and Karst

Photo of interior of Jacob's Cave showing a variety of speleothems.

With more than 7,000 caves, Missouri is known as "the Cave State." This is because much of Missouri is a karst landscape of porous limestone and dolomite, where caves, springs, sinkholes, and natural bridges form. These features support unique communities of animals, including threatened and endangered species.

The word karst is the German name for the Krš (or Kras) region on the border between Slovenia and Italy, which has a similar limestone topography. It’s used to describe this type of unique geology of caves, sinkholes, and springs, no matter where on Earth it occurs.

The Karst Cycle

Slightly acidic groundwater flows through cracks in limestone or dolomite, slowly dissolving the rock. The cracks widen to form cavities and eventually a subterranean drainage system. The creeks that flow through caves come from surface water that has seeped downward.

When a cave is below the water table, it is filled entirely with water. (Well-drillers search for these water-filled pockets.) When the cave is above the water table, the cave has air in it and its water flows ever downward. Wherever cave water exits the rock and flows into the open air, it is called a spring.

Some of our largest caves formed ages ago as completely water-filled cavities. Over geologic time, the Ozark Plateau was uplifted, and rivers carved valleys ever deeper into the bedrock, creating bluffs and causing cave passages to be above the water table and to drain.

As the slightly acidic water continues its etching of the rocks, sinkholes can occur where the roof of a cave, and the soil above it, collapse downward into the cave system. When rainwater collects in these depressions, sinkhole ponds form.

When an otherwise normal surface creek disappears underground, emptying into the water table below, it’s called a losing stream.

Natural bridges in karst landscapes represent the last vestiges of an otherwise completely collapsed cave.

Inside a cave, the formation of speleothems (stalactites, stalagmites, soda straws, dripstone, flowstone, and so on) represent the cave’s old age, as water crystallizes previously dissolved minerals, basically reversing the cave-making process, slowly filling the cave back up with rock.

All the land through which water moves into groundwater or into springs or caves is called a recharge area. For a single cave system, this area can be many miles wide. Pollutants, such as agricultural chemicals and animal waste, roadway runoff, leaking septic tanks, contaminants from trash thrown into sinkholes, and even excess silt from a variety of construction and agricultural earthworks, can seep into the groundwater, polluting caves, springs, and well water.

Karst Features

Cave and karst ecological communities are interdependent and often overlap. Browse Aquatic Caves, Sinkholes and Sinkhole Ponds, Springs, and Terrestrial Caves under Related Habitats below.

 

Most of our caves are in the Ozark Highlands ecoregion, where they occur in soluble dolomite or limestone. Caves also occur in sandstone or igneous rocks and may be found in the Osage Plains and Central Dissected Till Plains ecoregions. There are almost no caves in northwestern Missouri and in the Bootheel lowlands.

Media
Photo of path rush, closeup showing drying fruits.
Species Types
Scientific Name
Juncus spp. and Luzula spp.
Description
Missouri has 24 species in the rush family. Distinguishing between these grasslike plants can be tricky, but it’s easy to learn some basics about the group.
Media
Photo of eastern woodland sedge plant growing among leaf litter.
Species Types
Scientific Name
Carex, Schoenoplectus, Scirpus, and other genera
Description
Missouri has more than 200 species in the sedge family. Distinguishing between these grasslike plants can be difficult, but it’s easy to learn some basics about the group.
Media
Photo of a bristly cave crayfish, viewed from the side.
Species Types
Scientific Name
Cambarus setosus
Description
The bristly cave crayfish is a whitish crayfish with small, unpigmented eyes and long, slender pincers with noticeable setae (bristles). It lives in caves in the Springfield Plateau region of the Ozarks.
Media
Meek's Crayfish
Species Types
Scientific Name
Faxonius meeki (formerly Orconectes meeki)
Description
The pincers of Meek's crayfish are sprinkled with many blackish spots. There is a dark spot near the tubercle at the base of the moveable finger. In Missouri, this rare crayfish occurs in only a few tributaries of Table Rock Lake in Stone County.
Media
Photo of a pink planarian on a rock.
Species Types
Scientific Name
Dugesia, Planaria, and other genera
Description
Unlike their parasitic cousins in the flatworm group, turbellarians, or planarians, are tiny carnivores or detritus-eaters that glide smoothly across submerged leaves and other objects.
Media
Image of a deceased pseudoscorpion on a US dime
Species Types
Scientific Name
Various species in the order Pseudoscorpionida
Description
Pseudoscorpions are unusual little arachnids. They look something like tiny scorpions but with a rounded (and nonvenomous) hind end. They're common but often overlooked.
Media
Camel cricket (cave cricket)
Species Types
Scientific Name
About 150 species in North America north of Mexico
Description
Camel crickets and cave crickets are odd-looking, hump-backed insects that are commonly found in caves, basements, cellars, and similar places.
Media
Photo of an adult stonefly on a leaf
Species Types
Scientific Name
Nearly 700 species in North America north of Mexico
Description
Stoneflies have a lot in common with mayflies, caddisflies, dragonflies, and dobsonflies: They begin life as aquatic larvae, then molt and become winged adults. Many fish find stoneflies irresistible, and anglers know it.
Media
Grotto sculpin side view photo with black background
Species Types
Scientific Name
Cottus specus
Description
The grotto sculpin is a rare fish adapted cave conditions. It has recently been designated an endangered species under the Federal Endangered Species Act. It's found only in Perry County, Missouri.
Media
Ozark cavefish side view photo with black background
Species Types
Scientific Name
Amblyopsis rosae
Description
The Ozark cavefish is small, colorless, and blind. It lives only in springs, cave streams, and underground waters. It has been declared Endangered in our state and as Threatened by the U.S. Fish and Wildlife Service.
Media
Image of a cave salamander
Species Types
Scientific Name
Eurycea lucifuga
Description
The cave salamander is a common amphibian of the Ozark Plateau. It lives in caves, springs, and rocky streams. Recognize it by its normally bright orange skin dotted with dark brown or black spots.
Media
Image of a grotto salamander
Species Types
Scientific Name
Eurycea spelaea
Description
Many people know Missouri as “the cave state,” and the grotto salamander is Missouri’s only species of blind salamander. A true troglobite, it lives in total darkness and has small eyes that are completely or partially covered by their pink or beige skin.
Media
Silver-haired bat in flight.
Species Types
Scientific Name
About 14 species in Missouri
Description
Bats are the only mammals capable of sustained flight. At least 14 species of bats occur in Missouri; they are all relatively small, and they eat insects. Many of them are declining.
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