Ozark Karst Ecosystem

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Why the Conservancy Selected This Site
The Ozark Mountain region of northwest Arkansas is known to many for its beautiful woodlands, world-class rivers, rugged trails, and scenic vistas. But underneath lies a hidden biological treasure.

Miles of underground caves have been carved out over millennia by water seeping through porous soil and dissolving the limestone bedrock below. The term "karst" is used to define this landscape of sinkholes, fractures, underground streams and strings of limestone caverns.

The Ozark karst ecosystem covers portions of ten Arkansas counties and extends into Oklahoma and Missouri. It is home to a host of unique and extremely rare animals, some of which are found nowhere else in the world. Bats, fish, salamanders, and crayfish all coexist here, but degraded water quality and increased disturbance threaten their survival.

Lachlan Cave
© Tim Snell/TNC

Threats
The key to protecting karst habitat lies largely in improving water quality within a cave's recharge area -- the area that supplies water to the cave aquifer. Aquatic cave creatures are extremely sensitive, and any impurities in a cave's water supply can send them into decline. Threats to water quality include an increase in small livestock production and reduction in the extent of woodlands occurring in surrounding areas. In addition, urbanization is impacting water quality.

Cave systems must remain physically undisturbed and this requires continuous monitoring of cave entrances. Woodlands and related plant communities must also remain intact for foraging and watershed/aquifer protection.

Animals
The Ozark Karst Ecosystem harbors six species recognized under the federal Endangered Species Act. Those listed as endangered are:

Two crayfish species (Cambarus aculabrum) and (Cambarus zophonastes)
Ozark big-eared bat (Corynorhinus townsendii ingens)
Gray bat (Myotis grisescens)
Indiana bat (Myotis sodalis)

The Ozark cavefish (Amblyopsis rosae) is listed as threatened.

Our Conservation Strategy
The Nature Conservancy's Ozark Highlands Office in Fayetteville is working with community groups, landowners, public agencies and other partners to improve groundwater quality and to develop solutions for handling waste and hazardous materials that make their way into cave aquifers. By raising awareness of the significance of Ozark karst habitat, and by offering incentives to landowners to practice conservation techniques on their lands and in their communities, the Conservancy is addressing water quality issues in both agricultural and residential settings. This, of course, has the added benefit of improving the drinking, swimming, and fishing water for those of us above ground as well.

What the Conservancy Has Done/Is Doing
The Nature Conservancy owns or has a management interest in more than a dozen Ozark caves, including Bear Hollow Cave in Bella Vista, Arkansas. The Conservancy intends to protect a suite of cave systems in Arkansas, Missouri, and Oklahoma built around the known life history needs of cave crayfish, Ozark big-eared bat, and Ozark cavefish that also captures related elements of global significance. Some 10,000 non-contiguous acres in the Ozarks, Springfield Plateau and Elk River Hills have been identified for cave entrance, bat foraging, and cave recharge conservation areas. At these sites, the Conservancy will take biological inventories and continue to monitor and research rare species.

Preserves/Projects/Places to Visit
Bear Hollow Cave

Press Releases:
Millipedes Found in Arkansas Caves are New to Science
Owner's love of Ozarks land spawns gift to The Nature Conservancy

Learn More about the Conservancy's subterranean conservation work and see images of creatures that dwell in caves.

Download a printable karst ecosystem fact sheet (PDF).