Natural flow regimes represent the hydrologic conditions to which native aquatic organisms are best adapted. We completed a regional river classification and quantitative descriptions of each natural flow regime for the Ozark–Ouachita Interior Highlands region of Arkansas, Missouri and Oklahoma. On the basis of daily flow records from 64 reference streams, seven natural flow regimes were identified with mixture model cluster analysis: Groundwater Stable, Groundwater, Groundwater Flashy, Perennial Runoff, Runoff Flashy, Intermittent Runoff and Intermittent Flashy. Sets of flow metrics were selected that best quantified nine ecologically important components of these natural flow regimes. An uncertainty analysis was performed to avoid selecting metrics strongly affected by measurement uncertainty that can result from short periods of record. Measurement uncertainties (bias, precision and accuracy) were assessed for 170 commonly used flow metrics. The ranges of variability expected for select flow metrics under natural conditions were quantified for each flow regime to provide a reference for future assessments of hydrologic alteration. A random forest model was used to predict the natural flow regimes of all stream segments in the study area based on climate and catchment characteristics, and a map was produced. The geographic distribution of flow regimes suggested distinct ecohydrological regions that may be useful for conservation planning. This project provides a hydrologic foundation for future examination of flow–ecology relationships in the region. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

A variety of veterinary pharmaceuticals and pesticides are used on beef cattle feed yards to enhance growth and health of cattle and to control unwanted pests and parasites. Because growth promoters and antibiotics have recently been detected on particulate matter emanating from feed yards, we examined wildflowers collected near feed yards in the Southern Great Plains for the occurrence of antibiotics, β-agonists, other feed yard-related agrochemicals, and neonicotinoids used on regionally grown row crops. Wildflowers contained detectable concentrations of moxidectin, abamectin, monensin, ractopamine, and neonicotinoids (imidacloprid, thiamethoxam, and clothianidin). All wildflower samples contained at least one target analyte, while the majority (82%) contained multiple pharmaceuticals and/or pesticides, including 12% of wildflowers containing moxidectin, monensin, ractopamine, and a neonicotinoid. This preliminary survey demonstrates the potential for insect pollinators occurring near feed yards to become exposed to mixtures of agrochemicals derived from beef cattle feed yards and pesticides from row crop-based agriculture.

The semiarid Texas High Plains has a declining water supply for irrigated crop production because of unsustainable pumping from the Ogallala aquifer. Conversion of land from annual crops to limited‐irrigated perennial forages is an option for profitable land use. ‘WW‐B.Dahl’ old world bluestem [Bothriochloa bladhii (Retz) S.T. Blake, OWB] is a well‐adapted grass known for deterring some soil‐dwelling insects, but effects of OWB on insect pollinators are unknown. The aim of this study was to determine whether adapted forage types (species or mixtures) affected insect pollinator abundance in pastures. Foraging insects were collected using bee bowls and compared among OWB alone, OWB mixed with alfalfa (Medicago sativa L.), alfalfa, and a native grass mix. Twenty‐one families from four orders of insects were recovered over 3 yr. Sweat bee (Hymenoptera: Halictidae) was the most abundant family, with 59% of the total number of insects collected. Honey bees (Hymenoptera: Apidae) constituted an additional 17% of the total number of insects collected, with hover flies (Diptera: Syrphidae) and skippers (Lepidoptera: Hesperiidae) found in lesser abundances. Interactions between forage type and years restricted consistent forage‐type effects. In general, the lowest abundances of foraging insects were commonly found in OWB growing alone, especially of the native, ground‐nesting sweat bee, whereas greater abundances were more commonly found in native grass and alfalfa pastures. Widespread adoption of WW‐B.Dahl OWB may reduce local numbers of foraging insects in the Texas High Plains, which could negatively affect pollinators in managed grasslands.

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