Endemic Flora and Fauna of Arkansas

Arkansas has an amazing diversity of plants and animals contained within its political boundaries. Forty-seven taxa are reported as Arkansas endemics, including seven plants, thirteen crustaceans (two amphipods, three isopods, eight crayfishes), nine insects (one mayfly, one caddisfly, three stoneflies, four beetles), ten snails, six fishes, and two salamanders

Pre-impoundment Limnological Study of the Strawberry River in Northeastern Arkansas

A study of pre-impoundment limnological characteristics of the Strawberry River was made from August, 1967 to June, 1968. Two collecting stations were established, one upstream which would not be inundated and a lower station which would be inundated when impoundment was complete. The Strawberry River was characterized by high alkalinity and pH, low carbon dioxide and turbidity, and adequate oxygen values. Plankton was characterized by limited numbers of Staurastrum, Gomphonema, and Rotatoria. Pool-riffle communities were ill-defined. Chironomidae, Oligochaeta and Ephemeroptera were dominant pool macroinvertebrates among 13 taxa collected. Of the 20 taxa collected in riffles Trichoptera, Ephemeroptera, Simuliidae and Chironomidae were the most numerous. Longitudinal zonation was characterized by an increase in species and numbers of pool benthic macroinvertebrates from headwater to downstream areas. Numerical standing crop was recorded for pools on 8 June 1968 and riffles on 30 September 1967. A total of 1979 fishes constituting 49 species were taken in this study. Station I and II pools yielded 242 and 185 fishes/ha respectively, Dorosoma cepedianum and Moxostoma erythrurum being the dominant forms. The substantial populations of Dorosoma cepedianum seemingly are supported by debris and allochthonous materials and not on the sparse plankton present. Station I and II riffles yielded 2896 and 1108 fishes/ha respectively, Etheostoma caeruleum and Percina caprodes being most numerous. Longitudinal zonation was characterized by decrease in number/ha and species present from headwater to downstream areas

Millipeds (Arthropoda: Diplopoda) of the Ark - La - Tex. VI. New Geographic Distributional Records from Select Counties of Arkansas

We continue to report, in the sixth of a series of papers, new geographic records for millipeds of the state, including noteworthy records for some taxa collected from Crowley’s Ridge in eastern Arkansas. This contribution documents 47 new co. records and includes records for 19 species within 9 families and 5 orders. More uncommon millipeds found included Okliulus carpenteri (Parajulidae), Eurymerodesmus newtonus (Eurymerodesmidae), Pseudopolydesmus minor (Polydesmidae) and undescribed species of Ethojulus (Parajulidae) and Nannaria (Xystodesmidae). Undoubtedly, additional records will be reported in the future as several gaps in the distribution of Arkansas millipeds remain

Aquatic Macroinvertebrates of the Strawberry River System in North-Central Arkansas

The Strav/berry River has been designated an Extraordinary Resource Water, an Ecologically Sensitive Water Body, and a Natural and Scenic Waterway. As such, it is particularly important that the biodiversity of this river system be documented thoroughly. The purpose of this research was to develop a comprehensive list of the aquatic macroinvertebrates of the Strawberry River and its major tributaries. The information was developed from a thorough literature review and by examining specimens housed in various collections of the Arkansas State University Museum of Zoology and collections of the authors. The latter included 9 collections at 4 sites along the mainstream and 17 collections from 8 tributaries. To date, 313 species of aquatic macroinvertebrates are known to occur in the Strawberry River system. Among the freshwater mussels, 1is listed and 7 are ranked: Leptodea leptodon (Federal list-endangered, SI), Cyprogenia aberti, Lasmigona costata, and Quadrula cylindrica (S2), Cyclonaias tuberculata, Strophitus undulatus, and Villosa lienosa (S3). Of25 stonefly species known to be endemic to the Interior Highlands, 7 occur in this system

The Ticks (Arachnida: Acari: Ixodida) of Arkansas

Although ticks are a nuisance to humans and other animals, they are an important part of the biota of North America. In addition, they are vectors of many tick-borne disease agents that can negatively affect higher vertebrates. In Arkansas, there have been no recent comprehensive summaries of the ticks (Acari: Ixodida) in the last 40+ yrs. Here, we provide a summary of the ticks of the state and note the disease agents they can transmit

Energy Dissipation and Air Entrainment in a Stepped Storm Waterway: an Experimental Study

For the last three decades, research focused on steep stepped chutes. Few studies considered flat-slope stepped geometries such as stepped storm waterways or culverts. In this study, experiments were conducted in a large, flat stepped chute (~3.4 degrees) based upon a Froude similitude. Three basic flow regimes were observed: nappe flow without hydraulic jump, transition flow, and skimming flow. Detailed air-water flow measurements were conducted. The results allow a complete characterization of the air concentration and bubble count rate distributions, as well as an accurate estimate of the rate of energy dissipation. The flow resistance, expressed in terms of a modified friction slope, was found to be about 2.5 times greater than in smooth-chute flow. A comparison between smooth- and stepped-invert flows shows that greater aeration and larger residence times take place in the latter geometry. The result confirms the air-water mass transfer potential of stepped cascades, even for flat slopes