Time filter

Source Type

Brookings, SD, United States

South Dakota State University is a public research university located in Brookings, South Dakota. It is the state's largest and second oldest university. A land-grant university and sun grant university, founded under the provisions of the 1862 Morrill Act, SDSU offers programs of study required by, or harmonious to, this Act. In step with this land-grant heritage and mission, SDSU has a special focus on academic programs in agriculture, engineering, nursing, and pharmacy, as well as the liberal arts. The Carnegie Foundation for the Advancement of Teaching classifies SDSU as a Research University with high research activity. The graduate program is classified as Doctoral/Science, Technology, Engineering, Math dominant. SDSU is governed by the South Dakota Board of Regents, which governs the state's six public universities and two special schools. Wikipedia.

Although habitat networks show promise for conservation planning at regional scales, their spatiotemporal dynamics have not been well studied, especially in climatesensitive landscapes. Here I use satellite remote sensing to compile wetland habitat networks from the Prairie Pothole Region (PPR) of North America. An ensemble of networks assembled across a hydrologie gradient from deluge to drought and a range of representative dispersal distances exhibits power-law scaling of important topological parameters. Prairie wetland networks are "meso-worlds" with mean topological distance increasing faster with network size than small-world networks, but slower than a regular lattice (or "large world"). This scaling implies rapid dispersal through wetland networks without some of the risks associated with "small worlds" (e.g., extremely rapid propagation of disease or disturbance). Retrospective analysis of wetland networks establishes a climatic envelope for landscape connectivity in the PPR, where I show that a changing climate might severely impact metapopulation viability and restrict long-distance dispersal and range shifts. More generally, this study demonstrates an efficient approach to conservation planning at a level of abstraction addressing key drivers of the global biodiversity crisis: habitat fragmentation and climatic change. © 2010 by the Ecological Society of America. Source

Johnston C.A.,South Dakota State University
Landscape Ecology | Year: 2014

Land area planted to row crops has expanded globally with increased demand for food and biofuels. Agricultural expansion in the Dakota Prairie Pothole Region (DPPR), USA affects a variety of agricultural and non-agricultural land-use types, including grasslands and wetlands that provide critical wildlife habitat and other ecosystem services. The purpose of this study was to quantify recent changes in rural land cover/land use, analyze trends, and interpret results in relation to climate, agronomic practice, and ethanol production. The primary data sources were 1980-2012 statewide cropland data from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service, and the USDA Cropland Data Layer, produced annually for the DPPR from 2006 through 2012. Area planted to corn or soybean row crops increased, and small grain (e.g., wheat, barley) area decreased significantly over the analysis period. Corn and soybean expanded by 27 % in the DPPR between 2010 and 2012 alone, an areal increase (+15,400 km2) larger than the U.S. state of Connecticut. This expansion displaced primarily small grains and grassland (e.g., pastures, haylands, remnant prairies). Grassland regularly exchanged land with corn and soybean, small grains, and wetlands and water. Corn and soybean had high inter-annual self-replacement values (68-80 %), and continuous corn/soy row cropping was the second most common combination over a three-year period, ranking after continuous grassland. Small grain self-replacement values were only 22-35 %, indicating frequent relocation in the landscape. Temporary gains in wetland and grassland area were attributed to unusually wet climatic conditions and late snowfalls that prevented crop planting. Nearly all of the region's ethanol refineries were located where corn and soybean crops constituted 50 % or more of the land area. Quantification of grassland losses in the U.S. Northern Plains requires evaluation of all land uses that interact with grasslands, and a longer term perspective that incorporates grassland as part of a normal land-use rotation. © 2013 Springer Science+Business Media Dordrecht. Source

Hansen M.C.,South Dakota State University | Loveland T.R.,U.S. Geological Survey
Remote Sensing of Environment | Year: 2012

Landsat data constitute the longest record of global-scale medium spatial resolution earth observation data. As a result, the current methods for large area monitoring of land cover change using medium spatial resolution imagery (10-50. m) typically employ Landsat data. Most large area products quantify forest cover change. Forests are a comparatively easy cover type to map as well as a current focus of environmental monitoring concerning the global carbon cycle and biodiversity loss. Among existing change products, supervised or knowledge-based characterization methods predominate. Radiometric correction methods vary significantly, largely as a function of geographic/algorithmic scale. For instance, products created by mosaicking per scene characterizations do not require radiometric normalization. On the other hand, methods that employ a single index or classification model over an entire study area do require radiometric normalization. Temporal updating of cover change varies between existing products as a function of regional acquisition frequency, cloud cover and seasonality. With the Landsat archive opened for free access to terrain-corrected data, future product generation will be more data intensive. Per scene, interactive analyses will no longer be viable. Coupling free and open access to large data volumes with improved processing power will result in automated image pre-processing and land cover characterization methods. Such methods will need to leverage high-performance computing capabilities in advancing the land cover monitoring discipline. Robust validation efforts will be required to quantify product accuracies in determining the optimal change characterization methodologies. © 2012 Elsevier Inc. Source

Ting F.C.K.,South Dakota State University
Coastal Engineering | Year: 2013

The turbulent velocity field associated with the breaking of plunging regular waves on a 3% plane slope was measured in a plane running parallel to the slope using a particle image velocimetry (PIV) system. The measurement plane was located within the wave bottom boundary layer. The horizontal distance from the point of incipient breaking to the center of the measurement area was approximately 12 times of the breaking depth. The same wave train was generated 36 times and in each trial three consecutive wave cycles were recorded at a sampling rate of 15. Hz. The measured velocity fields were separated into a mean flow and a turbulence component using the ensemble averaging technique. The impingement process of breaking-wave-generated vortices on the bottom was investigated. The results showed that the impact of a plunging wave vortex on the bottom was a highly transient and three-dimensional phenomenon. The vortex arrived at the bottom around the instant of maximum positive wave-induced velocity. The surge of turbulence continued for a time of about 2Hb/g, where Hb is breaker height and g is acceleration due to gravity. The impingement region was not stationary, but continued to travel onshore with an initial speed close to the wave celerity. The distributions of turbulent velocity fluctuations and related momentum fluxes depended on the types of vortices produced. Plunger vortices generated at incipient breaking in deeper water had the characteristics of a three-dimensional vortex loop with counter-rotating vorticity. Large apparent shear stresses were measured in the flow attachment and detachment zones in front and behind the vortex loop. Transverse vortices generated in the subsequent splash in shallower water produced an asymmetrical impingement pattern similar to that of an inclined jet; the downburst of turbulent fluid was deflected outward and shoreward resulting in large onshore fluxes of turbulence energy near the bottom. Large apparent shear stresses were measured in the impingement zone and wall jet region. The motions of glass spheres sliding along the bottom were investigated. It was found that the velocities of glass spheres impacted by downbursts could significantly exceed the wave-induced velocities. It was also found that glass spheres could be trapped by counter-rotating vortices and carried for considerable distances onshore. The measured data suggested that compared to spilling waves, downbursts in plunging waves would enhance onshore sediment transport. © 2013 Elsevier B.V. Source

Murphy B.P.,South Dakota State University | Murphy B.P.,University of Tasmania | Bowman D.M.J.S.,University of Tasmania
Ecology Letters | Year: 2012

Forest and savanna biomes dominate the tropics, yet factors controlling their distribution remain poorly understood. Climate is clearly important, but extensive savannas in some high rainfall areas suggest a decoupling of climate and vegetation. In some situations edaphic factors are important, with forest often associated with high nutrient availability. Fire also plays a key role in limiting forest, with fire exclusion often causing a switch from savanna to forest. These observations can be captured by a broad conceptual model with two components: (1) forest and savanna are alternative stable states, maintained by tree cover-fire feedbacks, (2) the interaction between tree growth rates and fire frequency limits forest development; any factor that increases growth (e.g. elevated availability of water, nutrients, CO 2), or decreases fire frequency, will favour canopy closure. This model is consistent with the range of environmental variables correlated with forest distribution, and with the current trend of forest expansion, likely driven by increasing CO 2 concentrations. Resolving the drivers of forest and savanna distribution has moved beyond simple correlative studies that are unlikely to establish ultimate causation. Experiments using Dynamic Global Vegetation Models, parameterised with measurements from each continent, provide an important tool for understanding the controls of these systems. © 2012 Blackwell Publishing Ltd/CNRS. Source

Discover hidden collaborations