David A. Haukos

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Depressional wetlands in agricultural landscapes are easily degraded by sediments and contaminants accumulated from their watersheds. Several best management practices can reduce transport of sediments into wetlands, including the establishment of vegetative buffers. We summarize the sources, transport dynamics, and effect of sediments, nutrients, and(More)
Playas are the primary wetland system in the Southern Great Plains (SGP) of North America providing critical stopover habitats for migratory birds in the Western Hemisphere. Collectively, these wetlands form the keystone ecosystem in this region supporting biodiversity for North America and provide habitat for native plants and animals that are essential(More)
We examined pesticide contamination in sediments from depressional playa wetlands embedded in the three dominant land-use types in the western High Plains and Rainwater Basin of the United States including cropland, perennial grassland enrolled in conservation programs (e.g., Conservation Reserve Program [CRP]), and native grassland or reference condition.(More)
The cloacal cestode Cloacotaenia megalops is one of the most common helminths of waterfowl. We investigated the effect of this parasite on the body condition of wintering waterfowl populations and compared prevalence among age-sex classes, over time and between habitat types on the upper Gulf Coast of Texas (USA) from October 1986-February 2000. Greater(More)
There are 25,000–30,000 playa wetlands in the intensively cultivated Southern Great Plains of the United States. Knowledge of area and watershed influences on wetland flora are needed to guide their conservation. We surveyed plant-community composition in 224 playas over 360,000 km 2 and examined the relationships of species richness and diversity(More)
Breeding-bird communities inhabiting northern prairie wetlands have been shown to have higher densities and diversities in wetlands with a well-interspersed 50:50 vegetative cover:water ratio than in those wetlands with a higher or lower proportion of cover. Potential reasons for such a response include increased food or visual isolation and spacing of(More)
Conservation of wildlife depends on an understanding of the interactions between animal movements and key landscape factors. Habitat requirements of wide-ranging species often vary spatially, but quantitative assessment of variation among replicated studies at multiple sites is rare. We investigated patterns of space use for 10 populations of two closely(More)
Frequency and duration of playa inundation (i.e., hydroperiod) are major influences on the spatial and temporal distribution of flora and fauna in the western Great Plains. We used a 10-year data set of 221 playa wetlands to develop models of factors influencing the probability of a playa being flooded during January. We evaluated the relative influence of(More)
Pesticides have been implicated in widespread amphibian declines. We assessed acute and chronic toxicity of two widely used herbicides to larval New Mexico (Spea multiplicata) and Plains (S. bombifrons) spadefoots from cropland and native grassland playas. Roundup WeatherMAX (WM) toxicity estimates (48- and 216-h LC(50); 48-h LC(1)) for both species were(More)
Playa wetlands provide functions critical to the existence of life on the High Plains portion of the Great Plains, including surface drainage, aquifer recharge, and wildlife habitat. These small, circular, isolated depressional wetlands with closed watersheds have a dynamic, unpredictable hydroperiod, which is essential to the maintenance of biodiversity.(More)