Biomass Dynamics of Tipula (Insecta: Diptera) in Forested Streams of the Interior Highlands, Arkansas

Abundance patterns of aquatic macroinvertebrates that utilize coarse particulate organic matter as a food source are important indicators of non--point source pollution associated with silviculture activities. This group, referred to as shredders, typically decreases in abundance as its food source—primarily leaves—is removed from the ecosystem. We tested whether larval biomass of the crane fly Tipula, a common member of the group, was an effective estimator of shredder abundance. Additionally, we used regression analysis to test whether the length to dry mass relationship of Tipula differed among geographic regions, between seasons, and between years. Results did not indicate significant differences in the relationship among these variables. Thus, we concluded that a general length to dry mass relationship was appropriate for Tipula in streams of the Interior Highlands. Our results were similar to those reported from North Carolina and Virginia. Tipula biomass was positively correlated with the total richness of the macroinvertebrate assemblage, a common measurement of stream quality, but was not correlated with the numerical abundance of the shredder functional feeding group. Thus, we concluded that Tipula biomass would not be an effective surrogate for whole assemblage metrics in biological assessments

Winter and Spring Water Quality of the Big Creek Watershed, Craighead County, Arkansas: Nutrients, Habitat, and Macroinvertebrates

The objective of this study was to assess the water quality of the Big Creek watershed during the winter and spring of 2002 by analyzing water physical, chemical variables, aquatic macro-invertebrates, and habitat. The Big Creek watershed, arising on Crowley\u27s Ridge in northeast Arkansas, is a small deltaic watershed and is an area of intense cultivation. Four stations, Big Creek Upper (BCU), Mud Creek (MC),Lost Creek (LC), and Big Creek Lower (BCL) were established for this study from Big Creek, Mud Creek and Lost Creek. Water samples were collected on a weekly basis for 10 weeks from January 2002 through March 2002. We analyzed these streams for temperature, pH, D.O., conductivity, TSS, chlorophyll- a, DOC, total N and P, total dissolved N and P, nitrate, ammonium, and soluble reactive phosphorus. During this time period, we also sampled aquatic macroinvertebrates and assessed stream habitat according to USEPA rapid bioassessment protocols. Overall, nutrients and TSS were high, pH fluctuated from 5.8 to 7.8, and D.O. was moderate to high, ranging from 6.75 to 13.24 mg/L. Generally, physical and chemical water variables were correlated with changes in stream discharge. For a 20-jab dip-net sample, macroinvertebrate species richness ranged from 9 to 23 taxa, while abundance ranged from 38 to 209 individuals per station. Physical habitat index scores ranged from 75 to 104 (maximum of 200) indicating marginal physical habitat. We report that this watershed has high concentrations of nutrients and suspended solids during the winter and spring wet season and that the macroinvertebrate communities are influenced by stream conditions, including marginal physical habitat

B-type natriuretic peptide and renal function in the diagnosis of heart failure: An analysis from the BNP multinational study

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