Steven D. Warren

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Microbiotic crusts are important components of many aridland soils. Research on crusts typically focuses on the increase in soil fertility due to N-fixing micro-organisms, the stabilization of soils against water and wind erosion and the impact of disturbance on N-cycling. The effect of microbiotic crusts on the associated plant community has received(More)
Oedipoda caerulescens (blue-winged grasshopper) and Cicindela hybrida (northern dune tiger beetle) are protected insects in Germany and elsewhere. They are known to occur on sparsely vegetated, sandy soil. Populations of the two insects were evaluated in relation to physical soil disturbance on four military training areas in Germany to determine if the(More)
Variation in the computation of slope from digital elevation data can result in significantly different slope values and can, in turn, lead to widely varying estimates of environmental phenomena such as soil erosion that are highly dependent on slope. Ten methods of computing slope from distributed elevation data, utilizing capabilities inherent in five(More)
a Center for Environmental Management of Military Lands, Colorado State University, Fort Collins, CO 80523-1490, United States b Institute for Environmental Sciences, University of Koblenz-Landau, D-76829 Landau, Germany c Department of Disturbance Ecology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, D-95440 Bayreuth,(More)
A study was conducted on three U.S. military training areas to validate the Unit Stream Power Erosion and Deposition (USPED) model, a 3-dimensional enhancement to the Universal Soil Loss Equation (USLE). The USPED model differs from other USLE-based models in the manner in which it handles the influence of topography on the erosion process. As a result, the(More)
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The prevention of biodiversity loss in agricultural landscapes to protect ecosystem stability and functions is of major importance to stabilize overall diversity. Intense agriculture leads to a loss in species richness and homogenization of species pools, but the processes behind are poorly understood due to a lack of systematic case studies: The specific(More)
Many barrel or columnar cacti, including some in the Atacama Desert, produce their reproductive tissue at or near the terminal apices of solitary or minimally branched stems that lean toward the equator, reportedly to maximize exposure to photosynthetically active radiation (PAR). Those with lateral reproductive tissue, often produce the tissue on the(More)
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