Located in Woodward County in northwestern Oklahoma 16 km SW of Freedom, Oklahoma, The University of Central Oklahoma's (UCO) Selman Living Laboratory (SLL), occupies 129.5 ha of mixed-grass-gypsum prairie in Woodward County. The SLL site was formerly grazing lands, operated by a succession of owners including most recently the historic Selman Ranch originally homesteaded in the early 1900s.  It is in the Central Great Plains mixed grass prairie ecoregion for Oklahoma (Oklahoma Biodiversity Task Force, 1996). The University of Central Oklahoma acquired the SLL through a combination of donations and purchases, due to Mrs. Betty Selman's desire to protect and preserve some of the large caves on her ranch for future research and education.  Recently Mrs. Selman donated four acres for astronomy facilities. This has become the SLL.

Prairie and Canyon Landscape in the Selman Living Laboratory Area

There have been few studies of either terrestrial or aquatic ecosystems in gypsum areas anywhere in the world, including Oklahoma.  World studies have been limited to floral aspects of gypsum communities in Spain, Mexico, Africa and Australia (Parsons, 1976).   Oklahoma studies have been mainly descriptive, cataloging subsets of the biota.  Knowledge of the biota is still lacking however, especially the aquatic fauna (Barber, 1979) .

A number of vertebrate species classified by either the United States Fish and Wildlife Service, or the Oklahoma Department of Wildlife Conservation as endangered, threatened, or of special concern, occur on or near the SLL.  These include the Arkansas River Shiner, Arkansas River Speckled Chub, Arkansas Darter, Texas Horned Lizard, Lesser Prairie Chicken, Interior Least Tern, Peregrine Falcon, Bald Eagle, Whooping Crane, Prairie Falcon, Ferruginous Hawk, and Swift Fox (data from the Oklahoma Biological Survey).  The best known biota at the SLL is that of the caves, due to Black (1971) and the work done by William Caire of The University of Central Oklahoma and his students, but much updating is needed, and the cave aquatic biota is poorly known.

Bats are an important component of the natural ecosystems of North America.  They contribute to important ecosystem services such as insect control and nutrient cycling. Their populations are declining due to pesticides and habitat destruction, and 3 of Oklahoma's 21 species of bats are on the Federal Endangered Species list: the Indiana Bat, the Gray Bat, and a subspecies of Townsend's Big-eared Bat.  These endangered species occur in eastern Oklahoma, and most conservation efforts have been directed there rather than in the West, though bats are important there as well.  The migratory Mexican Free-tailed Bat has a few very large (several hundred thousand to millions of individuals) maternity roosts in NW Oklahoma near the northern edge of the species' geographic distribution. The Oklahoma Department of Wildlife Conservation (ODWC) recognized the biological significance of these caves and funded the purchase of one maternity cave located 1 km from the SLL.  ODWC uses the cave not only for conservation, but for a very effective education program, and in conjunction with the SLL the cave, known as the Selman Bat Cave, offers additional research and education opportunities for individuals at the SLL.

The cave myotis also needs protection because it masses by the thousands in a few isolated caves to hibernate. This species hibernates in the Selman Cave System at the SLL from October to late March. The Selman Cave System has the largest population of hibernating cave myotis in Oklahoma, in some years exceeding 50,000 bats. The SLL provides protection to the cave system and it is an excellent site for research and conservation education regarding caves and their biota. When students and the general public experience the plight of America's ecosystems first hand, it is much easier for them to champion conservation and biodiversity causes` to others.

The Selman Cave System provides roosting habitat for other important species of bats: the big brown bat and the eastern Pipistrelle. The cave was utilized more extensively in the past than at present by another species, Townsend's big-eared bat, which seemingly has become less common through the years. This species is especially prone to disturbance by humans. The pallid cave bat utilizes the cave system as a night roost. Numerous studies on bat ecology and conservation have been conducted at the Selman Cave System (see below under Significant Research & Education), and other caves on the SLL and in the immediate vicinity, are available for researchers and students.

The cave system is also utilized by numerous other forms of life (Black, 1971) that have not been studied extensively in gypsum cave systems. These include tiger salamanders; cave crickets, crayfish, various beetles and other insects, woodrats and mice, bat parasites and snakes. The gypsum caves are potential sites for significant archeological and paleontological studies since they serve as natural fossil traps. Few educational facilities in the United States include gypsum caves for study.

Description

Environmentally, the SLL is considerably different from all other outdoor living laboratories and field stations in North America.

Climate: Climatically, the SLL exists in a semiarid region with a mean annual temperature of 14.4 C and a mean annual precipitation of 60.5 mm. Winters are moderate with occasional winter storms and periods of several days duration with below freezing temperatures and snow cover.  Summers are warm to hot.  Thunderstorms occur regularly in spring and summer, and between 1950 and 1995 there were 31 tornadoes in the area.

Geology: The SLL is located in the Cimarron Gypsum Hills amid rolling hills and plains (Lardie, 1982).  Escarpments have developed on interbedded Permian gypsum and shales. Permian Redbed deposits of red sandstones, siltstone, gypsum, and shale are locally common.  Caverns and sinkholes occur due to ground water flow having dissolved away portions of the gypsum. Biologically, the topography and geology of the area contribute to a unique ecosystem. For example, Lardie (1978) indicated that the Cimarron Gypsum Hills are unique from a herpetological aspect in that certain western and eastern species may be rare elsewhere in Oklahoma.  In northwestern Oklahoma, the western diamondback rattlesnake is most commonly found in the gypsum hills (Lardie and Black, 1981).

Cattle Grazing Mixed Grass Prairie Adjacent to the Selman Living Laboratory

Soils: The two major soil associations found on the SLL are the St. Paul-Carey-Woodward Association with gently sloping loamy redbeds and the Vernon-Cottonwood Association of dissected gypsum plains. The three main soil types in these associations are the Vernon-Cottonwood Complex, the Vernon Clay Loam of 5-12% slope, and the Lincoln Soils (Woodward County Soil Survey, 1963). These soils have developed under native grasses and in gypsum clay areas. Exposed gypsum rock exists in many areas.

Surface & Subsurface Hydrology: Salty Creek (a local name, the stream is unnamed on USGS topographic sheets) courses 1.2 km diagonally across the SLL.  It is confluent with Traders Creek, which drains into the Cimarron River.  Salty Creek supports a wetland riparian habitat. Underground springs surface on the SLL and drain to Salty Creek, as do streams from caves. Water in Salty Creek and that exiting the springs and caves has very high total dissolved solids (1825 ppm) due to calcium hardness (1455 ppm CaCO₃). Water quality information for the Selman Cave System exists in Black's (1971) cave biota publication.  Recent measurements (summer 2002) found Salty and Traders Creeks to have salinities of 1.7 to 2.4 ppt.  In a canyon just outside one cave mouth the water temperature was 12 ° C in late June 2002, warming to 30 ° downstream from the narrow, shaded canyon that the stream enters as it leaves the cave.

Flora: The SLL is located in the Mixed-grass Plains region of Oklahoma, which is a transition area from the tall grass prairies of the east to the short grass prairies of the high plains to the west.  Over 200 plant species have been identified on the site. Both sod and bunchgrass forms occur depending on local edaphic conditions. Common grasses include little bluestem, silver beardgrass, bluejoint, Indian grass, switch grass, grama grasses, and buffalo grass. Sandy areas include such shrubs as sand sage, sand plum, and sumacs. Trees located on the site include hackberries, elms, tamarisk, cottonwood, chittamwood, and willow. Prickly pear and small mammalaria cacti, a variety of mosses, ferns, and liverworts, as well as a large variety of flowering annuals and perennials occur. Wetland forms include cattails, rushes, sedges, watercress and various algae. Because this ranch has been grazed for many years the opportunity exists to monitor secondary succession of a grazed mixed grass plains back to a more natural condition. The reclamation and preservation of native grasslands is a vital and important conservation concern of the present worldwide biodiversity preservation movement.

Fauna: Although gypsum caves are not as biologically rich in diversity as eastern limestone caves, many species of wildlife use them for shelter and overwintering sites. The Selman Cave System contains the largest (approximately 50,000) known hibernating colony of the cave myotis in Oklahoma. Few studies exist documenting what forms of biota actually occur in gypsum caves (Black, 1971). Surface forms include porcupines, mule deer, woodrats, grasshopper mice, pocket mice, kangaroo rats, deer mice, coyotes, foxes, skunks, jackrabbits, cottontail rabbits, badgers, raccoons, rattlesnakes, king snakes, garter snakes, night snakes, horned lizards, collared lizards, six lined racerunners, tiger salamanders, toads, frogs, hawks, grassland bird species, bluebirds, great blue herons, prairie chickens, owls, scorpions, spiders, beetles, ants, bees, wasps and other insects and invertebrates.  Twenty species of fishes occur in Salty and Traders Creek on and downstream from SLL.

SELECTED BIBLIOGRAPHY

Barber, S. C. 1979. Floristic components of the gypsum hills and redbed plains area of southwestern Oklahoma. Southwestern Naturalist, 24:431-437.

Black, I. H. 1971. The cave life of Oklahoma: A preliminary study (excluding Chiroptera). Oklahoma Underground, 4(1 & 2): 2-53.

Lardie, R. L. 1982. A preliminary checklist of the amphibians and reptiles of northwestern Oklahoma (excluding the Oklahoma Panhandle). Bull. Okla. Herp. Soc.. 7:36-78.

Lardie, R. L. and J.H. Black, 1981. The amphibians and reptiles of the Cimarron Gypsum Hills region in northwestern Oklahoma. Bull, Okla. Herp. Soc. 5: 76-125.

Oklahoma Biodiversity Task Force. 1996. Oklahoma's Biodiversity Plan: A Sshared Vision for Conserving Our Natural Heritage. (Norman L. Murray, Editor). Oklahoma Department of Wildlife Conservation, Oklahoma City, Oklahoma, 129 pp.

Parsons, R.F. 1976.  Gypsophily in plants-a review.  Am. Midl. Nat., 96:1-96.

Woodward County Soil Survey. 1963. United States Department of Agriculture in cooperation with Oklahoma Agriculture Experiment Station. Series 1960, No.6, 108 pp.