Sandhill Research Articles

A Culinary History of the Nebraska Sand Hills: Recipes and Recollections from Prairie Kitchens by Christianna Reinhardt (review)

A Culinary History of the Nebraska Sand Hills: Recipes and Recollections from Prairie Kitchens by Christianna Reinhardt (review)

Use of the NatureServe Climate Change Vulnerability Index as an Assessment Tool for Reptiles and Amphibians: Lessons Learned.

Climate change threatens biodiversity globally, yet it can be challenging to predict which species may be most vulnerable. Given the scope of the problem, it is imperative to rapidly assess vulnerability and identify actions to decrease risk. Although a variety of tools have been developed to assess climate change vulnerability, few have been evaluated with regard to their suitability for certain taxonomic groups. Due to their ectothermic physiology, low vagility, and strong association with temporary wetlands, reptiles and amphibians may be particularly vulnerable relative to other groups. Here, we evaluate use of the NatureServe Climate Change Vulnerability Index (CCVI) to assess a large suite of herpetofauna from the Sand Hills Ecoregion of the southeastern United States. Although data were frequently lacking for certain variables (e.g., phenological response to climate change, genetic variation), sufficient data were available to evaluate all 117 species. Sensitivity analyses indicated that results were highly dependent on size of assessment area and climate scenario selection. In addition, several ecological traits common in, but relatively unique to, herpetofauna are likely to contribute to their vulnerability and need special consideration during the scoring process. Despite some limitations, the NatureServe CCVI was a useful tool for screening large numbers of reptile and amphibian species. We provide general recommendations as to how the CCVI tool's application to herpetofauna can be improved through more specific guidance to the user regarding how to incorporate unique physiological and behavioral traits into scoring existing sensitivity factors and through modification to the assessment tool itself.

Project Spotlight: NEXT beams meet constraints of Sand Hill Bridge

Project Spotlight: NEXT beams meet constraints of Sand Hill Bridge

Impacts of devegetation on the temporal evolution of soil saturated hydraulic conductivity in a vegetated sand dune area

Soil saturated hydraulic conductivity (K S ) is partly affected by vegetation activities, which can either increase K S by enhancing macropore flow or reduce K S by clogging pore space. Despite the complex interactions of K S with vegetation, the impact of devegetation on K S has not been adequately addressed, particularly in regions that are prone to drought-induced devegetation. In this study, the impacts of devegetation on K S in a native grassland-stabilized sand dune area were investigated by artificially controlling surface vegetation at an experimental site in the Nebraska Sand Hills. The experimental results revealed that the temporal evolution of K S at the site was mainly affected by the erosion processes triggered by devegetation. Over a short-term (about 1 year), the impact of devegetation on K S was negligible, owing to that the existence of dead root systems prevented erosion processes. By comparison, the long-term impact of devegetation on K S emerged when devegetation-induced erosion processes exposed deeper soil layers with higher K S . Particularly, the dunetop locations that experienced higher erosion rates had larger temporal changes in K S . Thus, the impacts of devegetation on K S mainly depended on two factors (i.e., time and topographic locations) that were related to erosion processes in this native grassland-stabilized sand dune area. To further investigate the ecohydrological implications of the temporal change in K S , a newly developed ecohydrological model was also employed, and the simulation results showed that the impacts of changes in K S on water balance components and biomass production were non-negligible and highly nonlinear. In spite of previous studies, the findings presented here demonstrate the close tie between near-surface hydrology and land surface evolution processes controlled by vegetation in sand dune areas, and highlight the importance of coupling eco-hydro-geomorphic interactions in the context of climate change.

Temporal and spatial variability in dune reactivation across the Nebraska Sand Hills, USA

The Nebraska Sand Hills is a stabilized dune field on the Great Plains of North America. Although it is well known that this dune field, like several others on the Great Plains, last experienced widespread activity during the Medieval Climatic Anomaly (MCA, ~AD 900–1300), spatial variation in the timing and nature of drought development is poorly constrained. To elucidate spatial trends in dune reactivation, samples potentially representing MCA activity across the Sand Hills were collected and dated using optically stimulated luminescence (OSL). Ages from the older part of the MCA were obtained from eolian sediments in the northwestern Sand Hills, while ages from later in the episode were obtained to the southeast, suggesting a geographic trend in the timing of revegetation of the dunes near the end of the drought. Revegetation likely occurred to the northwest initially as a result of renewed moisture availability from a rising water table in the interdunes, which serve as refugia for vegetation during times of drought. Vegetation then gradually spread to the southeastern Sand Hills. An additional spatial trend in ages is apparent in the chronology of linear dune mobilization across the Sand Hills. Linear dunes in the northwest are superimposed on megadunes and originated during the last reactivation, while linear dunes in the southeast are built around older cores of dunes and formed during several reactivations. Our geochronology reveals three episodes of eolian transport, including the MCA, in the formation of linear dunes in the southeast.

Determining the impacts of experimental forest plantation on groundwater recharge in the Nebraska Sand Hills (USA) using chloride and sulfate

Although impacts of land-use changes on groundwater recharge have been widely demonstrated across diverse environmental settings, most previous research has focused on the role of agriculture. This study investigates recharge impacts of tree plantations in a century-old experimental forest surrounded by mixed-grass prairie in the Northern High Plains (Nebraska National Forest), USA. Recharge was estimated using solute mass balance methods from unsaturated zone cores beneath 10 experimental plots with different vegetation and planting densities. Pine and cedar plantation plots had uniformly lower moisture contents and higher solute concentrations than grasslands. Cumulative solute concentrations were greatest beneath the plots with the highest planting densities (chloride concentrations 225–240 % and sulfate concentrations 175–230 % of the grassland plot). Estimated recharge rates beneath the dense plantations (4–10 mm yr−1) represent reductions of 86–94 % relative to the surrounding native grassland. Relationships between sulfate, chloride, and moisture content in the area’s relatively homogenous sandy soils confirm that the unsaturated zone solute signals reflect partitioning between drainage and evapotranspiration in this setting. This study is among the first to explore afforestation impacts on recharge beneath sandy soils and sulfate as a tracer of deep drainage.

The real “fire ants”: colony size and body size of workers influence the fate of boreal sand hill ants (Hymenoptera: Formicidae) after wildfires in Alberta, Canada

AbstractOver two summers following accidental May wildfires, total ant (Hymenoptera: Formicidae) forager catch and species richness did not change in jack pine woodlands on sand hills in central Alberta, Canada. However, one year after a fire, smaller ants, and those in smaller colonies, were more abundant in pitfall traps, based on analysis of response ratios for each ant species and relationships to a variety of life history and organismal traits. Nest type and polygyny had no effect on post-fire ant forager catch. The numerical responses of individual ant species appear to be idiosyncratic, but three species of ants that are sand specialists were found to be particularly resilient to fire.

Vadose zone lag time and potential 21st century climate change effects on spatially distributed groundwater recharge in the semi-arid Nebraska Sand Hills

Summary Deep drainage of water below plant root zones (potential groundwater recharge) will become groundwater recharge (GR) after a delay (or lag time) in which soil moisture traverses the vadose zone before reaching the water table. Depending on the thickness of the vadose zone, the magnitude of deep drainage, and soil hydraulic properties, lag times will vary broadly, exceeding decades to centuries in semi-arid and arid environments. Yet, studies of future climate change impacts to GR have typically avoided focusing on impacts beyond 100 years and often neglect to consider lag effects caused by the vadose zone. We investigate the effects of vadose zone lag time and potential 21st century climate change on the spatial distribution and timing of GR throughout the semi-arid Nebraska Sand Hills (NSH) region (∼50,000 km2). We propose a simple and rapid quantitative approach for assessment of the groundwater system response time to changes in climate. Understanding of such effects is needed for groundwater modeling, analysis of climate change impacts on groundwater, and the effective management and sustainability of future water resources. Lag time estimates are made using the pressure-based vertical velocity of soil moisture changes, equivalent to a kinematic wave approximation of Richards’ equation. The underlying assumptions (unit hydraulic gradient and relatively slow changes in climate) are supported by observations in the High Plains aquifer region, encompassing the NSH. The analysis relies on four sources of input data, including: Spatially distributed high resolution (1.1-km) GR rates (as the difference in 2000–2009 mean precipitation and evapotranspiration—estimated using a novel MODIS-based approach); thickness of the vadose zone—based on 30-m digital elevation models of the land surface and water table elevations; statistically downscaled estimates of future (2010–2099) potential GR rates from two hydroclimate model projections (WRCP CMIP3) with opposing GR trends; and estimates of hydraulic conductivity and vertical velocity of the vadose zone pressure changes using the van Genuchten–Mualem equation. We found that vadose zone lag times (with a mean GR rate of 78 mm/yr for 2000–2009) have an estimated spatial mean of 5.28 yrs (vertical velocity of 5.68 m/yr). End-of-century lag times (with mean potential GR rates of 128 and 61 mm/yr for 2090–2099) have estimated spatial means of 3.78 and 6.55 yrs (vertical velocities of 8.13 and 4.69 m/yr) for wet and dry scenarios, respectively. Findings suggest that the highly conductive materials (primarily sand deposits) and high potential GR rates in the NSH lead to relatively quick drainage of vadose zone water on the order of several years (less than a decade) for the entire 21st century. However, considerable spatial variations of lag times exist due to gradients in potential GR rates and the highly variable vadose zone thickness in the NSH.

Defining the reference condition for wadeable streams in the Sand Hills subdivision of the Southeastern Plains ecoregion, USA.

The Sand Hills subdivision of the Southeastern Plains ecoregion has been impacted by historical land uses over the past two centuries and, with the additive effects of contemporary land use, determining reference condition for streams in this region is a challenge. We identified reference condition based on the combined use of 3 independent selection methods. Method 1 involved use of a multivariate disturbance gradient derived from several stressors, method 2 was based on variation in channel morphology, and method 3 was based on passing 6 of 7 environmental criteria. Sites selected as reference from all 3 methods were considered primary reference, whereas those selected by 2 or 1 methods were considered secondary or tertiary reference, respectively. Sites not selected by any of the methods were considered non-reference. In addition, best professional judgment (BPJ) was used to exclude some sites from any reference class, and comparisons were made to examine the utility of BPJ. Non-metric multidimensional scaling indicated that use of BPJ may help designate non-reference sites when unidentified stressors are present. The macroinvertebrate community measures Ephemeroptera, Plecoptera, Trichoptera richness and North Carolina Biotic Index showed no differences between primary and secondary reference sites when BPJ was ignored. However, there was no significant difference among primary, secondary, and tertiary reference sites when BPJ was used. We underscore the importance of classifying reference conditions, especially in regions that have endured significant anthropogenic activity. We suggest that the use of secondary reference sites may enable construction of models that target a broader set of management interests.

A SQUID magnetometry system for a cryogenic neutron electric dipole moment experiment

1Current address: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USAPrecision magnetometry is an essential component of any neutron electric dipole moment experiment in order to correct shifts in the neutron precession frequency due to changes in the magnetic field. We have developed a magnetometry system using 12 SQUID sensors, designed to operate in 0.5K superfluid helium. The pick-up loops located near the neutron cell are connected to the SQUID sensors by ~2m twisted wire pairs. The SQUID readout cables are run via an intermediate stage at 4.2K. The system has been installed and tested in the cryoEDM apparatus at the ILL, Grenoble, and used to characterise the magnetic environment. Further tests in a suitable low noise environment confirm it meets our requirements.

Ultra-Low Cement Dosage Hill Sand Concrete’s Electric Flux and Carbonization Performance Study

Concrete durability is closely related to the national economy and social stability, environmental protection, sustainable development is a major research topic concrete materials science, engineering and technological problems are a major concern. This paper studies resistance to chloride Ion penetration performance and anti-carbonation of low cement concrete sand hill. And combined with the test results analysis and discussion the low dosage of cement to sand concrete electric flux and the influence of carbonization resistance.

The Waterloo Moraine: A watershed perspective

The Grand River, the largest river in southwestern Ontario, flows 311 km from Dundalk to Lake Erie. To mitigate flooding and low-flow extremes created by the removal of forest cover and wetlands, the Grand River Conservation Authority (GRCA) operates seven multi-purpose reservoirs. The ability to meet future human and ecological water needs depends both on the careful operation of the reservoir network and the protection, rehabilitation and enhancement of hydrologic and ecological functions provided by natural features such as the Waterloo Moraine, the largest moraine within the Grand River watershed. This moraine contains a complex set of stratigraphic and topographic elements, including extensive areas of sand hills and gravel terraces that readily allow precipitation to infiltrate and recharge several overburden aquifer systems. These aquifer systems discharge groundwater to the headwater wetlands and streams and contribute baseflow. This paper presents a watershed perspective of the importance of the Waterloo Moraine to the hydrology, water quality and ecology of the river system and urges the timely uptake of adaptive management and coordinated multi-scale planning (e.g. watershed, subwatershed and municipal) to safeguard the moraine’s natural functions.

Środowisko przyrodnicze i zagospodarowanie form eolicznych w gminie Szadek

Sand hills, dunes and sand sheets are eolian landforms, on which specific sensitive ecosystems develop. They are characteristic feature of many areas situated in central Po­land. Sandy areas with dunes are also found in the commune of Szadek. Wind-deposited sand bodies have accumulated on moraine plains, outwashes and floodplain terraces in the valleys of the Pichna and Brodnia rivers. Eolian formations have various shapes, with predominance of parabolic dunes, ridges and sand hills. They are built offine-grained and coarser sands 1-10 meters thick. Quartz dominates in their mineral composition. Sand-deposits are characterized by high permeability, which is why they produce dry ecosystems. Arid sands are covered by low-class pod sols, easily eroded by wind. For that reason this type of ecosystems should remain afforested, as the cutting down of trees can result in blowing away the soil and eventually destruction of the entire formation. Such situations are known to have happened in the past. In the commune of Szadek, the majority of the dunes are overgrown with forest, which is the most advantageous solution.

Sedimentary and OSL dating evidence for the development of the present Hobq desert landscape, northern China

The sedimentary sequence and landscape of the Hobq desert was observed through twelve profiles along five N-S sections extending through the entire desert. Aeolian sands were found to overlie the alluvial, diluvial, and lacustrine sediments in this desert. Optically stimulated luminescence (OSL) dating results were obtained from post-IR OSL signals of quartz fractions of sand samples at the bottom of sand dunes and hills by using the Double-SAR protocol. The OSL ages reveal that the latest sand accumulation began around 19 ka in the northwestern part and 9 ka in the eastern part of the Hobq Desert. Around 7 ka, the sand accumulation was strengthened and extended southward and northward 2 ka to develop the present desert landscape. Our study suggests that the aeolian sand accumulation around 19, 9 and 7 ka resulted from the weakening of the Asian summer monsoon over this region. However, the rapid development of the present Hobq desert landscape since 2 ka was likely triggered by human activities in this desert.

Microbial biomass and community structure in alkaline lakes of the Nebraska Sand Hills, USA

The many lakes present among the inactive dunes of the Nebraska Sand Hills are unique ecosystems that formed under particular conditions of local and regional geomorphology, hydrology and climate. They offer an exceptional opportunity to study the inter-relations between hydrology, microbial diversity, and biogeochemistry in comparatively closely-spaced bodies of water ranging in pH from neutral to alkaline. We analyzed for lipid biomarkers in the surficial sediments of six Sand Hills lakes, including alkanes, alkenes, alkanols, phytol, sterols, hopanoids, tetrahymanol, and phospholipid fatty acids. Overall, these biomarkers exist in significantly lower concentrations in the alkaline lakes of the Sand Hills than in ordinary neutral lakes. More specifically, microbial functional groups can be identified in the lake sediments on the basis of the biomarkers for which we analyzed. The presence of eukaryotic phototrophs is indicated by the detection of phytadienes, phytol, phytanol, diatomsterol, dinosterol, and polyunsaturated fatty acids. The detection of short-chain wax esters suggests the presence of anoxygenic autotrophic sulfur bacteria (purple and green sulfur bacteria). The phospholipid fatty acid (PLFA) profiles indicate the presence of sulfate-reducing bacteria in the sediment. Tetrahymanol and polyunsaturated fatty acids in the sediments suggest the presence of bacterivorous ciliates and phototrophic sulfur bacteria, which probably live at the chemocline. Our results reveal that there are unique and integrated ecosystems within the Sand Hills lakes that are defined by the close interactions between regional hydrology, geochemistry, and microbiology.

Quaternary eolian dunes in the Savannah River valley, Jasper County, South Carolina, USA

Sand hills in the Savannah River valley in Jasper County (South Carolina, USA) are interpreted as the remnants of parabolic eolian dunes composed of sand derived from the Savannah River and stabilized by vegetation under prevailing climate conditions. Optically stimulated luminescence ages reveal that most of the dunes were active ca. 40 to 19ka ago, coincident with the last glacial maximum (LGM) through early deglaciation. Modern surface winds are not sufficient for sustained eolian sand transport. When the dunes were active, winds blew at velocities of at least 4m/s from west to east, and some vegetation was present. The ratio of annual precipitation to potential evapotranspiration (P:PE) was less than the modern ratio of 1.23 and may have been <0.30, caused by stronger winds (which would have resulted in greater evaporation) and/or reduced precipitation. The Savannah River dunes are part of a larger assemblage of eolian dunes that were active in the eastern United States during and immediately after the LGM, suggesting that eolian sediment behavior in this region has been controlled by regional forcing mechanisms during the Quaternary.

Experimental Investigation of Soil Thermal Conductivity Over a Wide Temperature Range

The results are reported of an experimental investigation of the soil thermal conductivity over a wide temperature range, for various water contents and two soil types. The results are particularly important in predictions of underground heat transfer, which require a quantitative understanding of the coupled dependence of the soil thermal conductivity on texture, temperature, and water content. In the research, comprehensive sets of thermal conductivity for Ottawa sand (coarse soil) and Richmond Hill fine sandy loam (medium soil) are experimentally obtained using the guarded hot-plate method, for temperatures ranging from \(2\,^{\circ }\mathrm{C}\) to \(92\,^{\circ }\mathrm{C}\) and water contents varying from complete dryness to full saturation. For both soils, the thermal conductivity is observed to vary in three stages with respect to increasing water content: a very minor increase as water content increases to the permanent wilting point, a steep increase as water content further increases to field capacity, and a minor increase (for temperatures less than \(72\,^{\circ }\mathrm{C}\)) or decrease for (temperatures greater than \(72\,^{\circ }\mathrm{C}\)) when the field capacity is exceeded. Then, on the basis of gathered datasets, a similar \(Ke(S_{\mathrm{r}},T)\) form of the soil thermal conductivity model by Tarnawski et al. is used to empirically fit the data. The resulted correlations fit the data well with their overall root-relative-mean-square percentage errors of 4.7 % and 6.1 % for Ottawa sand and Richmond Hill fine sandy loam, respectively, and are suitable for most engineering applications.

Adaptive Evolution of Multiple Traits Through Multiple Mutations at a Single Gene

The identification of precise mutations is required for a complete understanding of the underlying molecular and evolutionary mechanisms driving adaptive phenotypic change. Using plasticine models in the field, we show that the light coat color of deer mice that recently colonized the light-colored soil of the Nebraska Sand Hills provides a strong selective advantage against visually hunting predators. Color variation in an admixed population suggests that this light Sand Hills phenotype is composed of multiple traits. We identified distinct regions within the Agouti locus associated with each color trait and found that only haplotypes associated with light trait values have evidence of selection. Thus, local adaptation is the result of independent selection on many mutations within a single locus, each with a specific effect on an adaptive phenotype, thereby minimizing pleiotropic consequences.

Palliser’s Triangle: Reconstructing the ‘central desert’ of the southwestern Canadian prairies during the late 1850s

Between 1857 and 1860 the British North American Expedition, led by Captain John Palliser, explored and surveyed the Canadian Prairies primarily to establish its suitability for agriculture and settlement. Historical and paleoclimate records indicate the Expedition coincided with below normal precipitation, leading to the perception of an arid or semi-arid region that would ‘forever be comparatively useless’ for agriculture. Today, this part of the Canadian Prairies is known as the Palliser Triangle, and is Canada’s productive dryland agricultural region. Here we present historic, geomorphologic, and chronometric evidence to reconstruct the landscape encountered by the Expedition. We contend that Palliser’s perception of the region was strongly influenced by his experience travelling through active sand dunes in the Middle Sand Hills of southeastern Alberta. At present, the dunes are entirely stabilized by vegetation, in contrast to Palliser’s report of ‘miles of burning sand’. Archival aerial photographs and optical ages of near-surface samples are used to reconstruct the landscape encountered by the Expedition in the Middle Sand Hills. Optical ages of presently stabilized sand dunes date primarily to between ad 1850 and 1934, peaking in c. ad 1925, and are indicative of a dune field undergoing reduction in activity, prior to the onset of 20th century droughts. Ages of interdune sand sheets further attest to regional dune activity occurring at least since ad 1750, concurrent with activity in other southern Canadian Prairie dune fields. Collectively, this evidence supports observations by Palliser of severe travelling due to bare sand conditions in 1857–1859. These conditions and Palliser’s inference of their extent influenced his perception of a ‘central desert’, thus delaying construction of the Canadian Pacific Railway along a southern route and postponing the westward colonization of Canada.

Application of multivariate heavy-tailed distributions to residuals in the estimation of genetic parameters of growth traits in beef cattle1

Assumptions of normality in most animal breeding applications may make inferences vulnerable to the presence of outliers. Heavy-tail densities are viable alternatives to normal distributions and provide robustness against unusual or outlying observations when used to model the densities of residual effects. Our objective is to compare estimates of genetic parameters by fitting multivariate normal (MN) or heavy-tail distributions [multivariate Student's t (MSt) and multivariate slash (MS)] for residuals in data of body birth weight (BBW), weaning (WW), and yearling (YW) weight traits in beef cattle. A total of 17,019 weight records for BBW, WW, and YW from 1998 through 2010 from a large commercial cow/calf operation in the sand hills of Nebraska were analyzed. Models included fixed effects of contemporary group and sire breed whereas animal and maternal effects were random and the degrees of freedom (v) was treated as unknown for MSt and MS. Model comparisons using deviance information criteria (DIC) favored MSt over MS and MN models, respectively. The posterior means [and 95% posterior probability intervals (PPI)] of v for the MSt and MS models were 5.28 (4.80, 5.85) and 1.88 (1.76, 2.00), respectively. Smaller values of posterior densities of v for MSt and MS models confirm that the assumption of normally distributed residuals is not adequate for the analysis of BBW, WW, and YW datasets. Posterior mean (PM) and posterior median (PD) estimates of direct and maternal genetic variances were the same and posterior densities of these parameters were found to be symmetric. The 95% PPI estimates from MN and MSt models for BBW did not overlap, which indicates significant difference between PM estimates from MN or MSt models. The observed antagonistic relationship between additive direct and additive maternal effects indicated that genetic evaluation and selection strategies will be sensitive to the assumed model for residuals.