The Treasures of the Ozark Plateau
Hensley, Steve, Endangered Species Bulletin
The Ozark Plateau ecosystem of eastern Oklahoma, western Arkansas, and southern Missouri boasts an exceptional assemblage of important hardwood forests, high quality rocky bottom clear streams, and unique springs and caves. It is also one of the fastest developing areas in the nation. In 1986, to conserve some of the region's richest biological resources, Congress established the Ozark Plateau National Wildlife Refuge.
The refuge is vital to ensuring the recovery of endangered and threatened Ozark cave species, reducing the need for future listing of additional species, and protecting large continuous stands of Ozark forest essential to interior forest nesting migratory birds. This refuge and additional areas are being protected through a partnership including private landowners, conservation and caving organizations, universities, tribes, and state and federal conservation agencies. With the help of these partners, management agreements have been developed with private landowners, and easements and lands have been purchased from willing sellers. The result is an ecosystem approach to protecting a variety of resources dependant on the Ozark's karst topography.
The Ozark Plateau NWR now consists of 10 tracts in Adair, Delaware, and Ottawa Counties, Oklahoma, totaling about 3,000 acres (1,215 hectares). Most are remote blocks of mature oak-hickory forest on the southwest edge of the Ozark Plateau bordering the Boston Mountains. They are underlain by Boone chert, a geological formation of alternating limestone and flint layers eroded to form steep hills, incised valleys, and prominent bluffs. Much of the drainage is underground, feeding a number of springs and caves. The refuge encompasses much of the drainage from a number of high gradient, rocky bottom, spring-fed Ozark streams.
Federally listed threatened or endangered species and species of concern that benefit from the refuge are the endangered Ozark big-eared bat (Corynorhinus townsendii ingens), gray bat (Myotis grisescens), and Indiana bat (Myotis sodalis); the threatened Ozark cavefish (Amblyopsis rosae); and species of concern like the eastern small-footed bat (Myotis leibii), southeastern bat (Myotis austroriparius), southeastern big-eared bat (Corynorhinus rafinesquii), longnose darter (Percina nasuta), Ozark cave crayfish (Cambarus aculabrum), Bowman's cave amphipod (Stygobromus bowmani), Ozark cave amphipod (Stygobromus ozarkensis), bat cave isopod (Caecidotea macropoda), and Ozark chinquapin (Castanea pumila var. ozarkensis).
Since 1981, the Oklahoma gray bat maternity colony population has increased from 56,600 to almost 150,000. Five gray bat maternity caves have been gated to prevent disturbance. Three of the caves maintain populations of about 10,000 bats each during the summer, and two maintain populations of around 20,000 each. The Ozark big-eared bat population in eastern Oklahoma and western Arkansas appears to be stable at about 2,000, with a few new sites continuing to be found. …