A researcher displays juvenile freshwater fat mucket mussels that will be used as stand-ins for rarer species in studies on water temperature tolerance. Study data will help researchers assess how vulnerable rare Oklahoma aquatic species will be to potential warming tied to climate change. Photo: David Martinez, USFWS. Download.
Several rare and distinctively-named creatures depend for survival on the cool, mountain-fed Little and Kiamichi River Basins in southeastern Oklahoma and southwestern Arkansas. At Little River National Wildlife Refuge and surrounding areas, the Ouachita rock pocketbook — a freshwater mussel — filters the water alongside two other endangered mussels, the scaleshell and winged mapleleaf. A small federally threatened fish called the leopard darter also hides in these upland streams.
Because streams in these river basins originate in the Ouachita Mountains, their water is relatively cool compared to streams in other ecosystems such as the Great Plains. High temperatures range from about 64 degrees Fahrenheit in winter to 84 degrees in summer — a range that suits popular game fish such as smallmouth bass.
But threats abound. Water pollution, agriculture runoff and the construction of dams and reservoirs have already shrunken habitat for these rare aquatic species. A historic drought is compounding the problem. And now, biologists speculate the fish and mussels could face another potential stressor: rising stream temperatures resulting from climate change, if projections by an intergovernmental panel prove accurate.