Aquatic Macroinvertebrates of the White River National Wildlife Refuge, Arkansas

The objectives of this study were to survey the diversity of the aquatic macroinvertebrates ofthe White River National Wildlife Refuge (WRNWR) and determine relative abundances and distributional and seasonal patterns. No comprehensive investigation of WRNWR aquatic macroinvertebrates had been conducted previously. Thirty sampling stations were established within WRNWR. Each station was sampled twice, providing 60 totalsamples, for 1.5 man hours witha Turtox Indestructible™ dip net. Three black light trap samples were taken to augment the species list. A total of 15,056 individuials representing 219 taxa was taken by dip net samples during the sampling period October 1989-September 1990. Insects comprised 76% ofthe organisms captured withColeoptera being the dominant group. The most abundant organism for WRNWR was Hydroporus vitlalipennis. Black light samples and literature records each revealed 21 additional taxa bringing the total taxa currently known from WRNWR to 261. Each of the 30 stations was assigned to one of four associations, which were defined by continuity of determined internal and external factors. The Climax-Isolation Association possessed the most stable and complex community structures; isolation by levees and natural boundaries and scarcity of human intervention probably accounted for this. The Congruent Lentic Association embraced communal structures ofgood quality but possessed factors limiting diversity. The Agriculturally Inflicted-White River Tributary Association supported relaItivelysimple aquatic macroinvertebrate communities. Finally, the Restricted Association consisted oftwo stations containingsignificant limiting factors resulting in concomitantly depauperate aquatic macroinvertebrate communities