Prairie Landscape Research Articles

Spatial Variability of L-Band Brightness Temperature during Freeze/Thaw Events over a Prairie Environment

Passive microwave measurements from space are known to be sensitive to the freeze/thaw (F/T) state of the land surface. These measurements are at a coarse spatial resolution (~15–50 km) and the spatial variability of the microwave emissions within a pixel can have important effects on the interpretation of the signal. An L-band ground-based microwave radiometer campaign was conducted in the Canadian Prairies during winter 2014–2015 to examine the spatial variability of surface emissions during frozen and thawed periods. Seven different sites within the Kenaston soil monitoring network were sampled five times between October 2014 and April 2015 with a mobile ground-based L-band radiometer system at approximately monthly intervals. The radiometer measurements showed that in a seemingly homogenous prairie landscape, the spatial variability of brightness temperature (TB) is non-negligible during both frozen and unfrozen soil conditions. Under frozen soil conditions, TB was negatively correlated with soil permittivity (εG). This correlation was related to soil moisture conditions before the main freezing event, showing that the soil ice volumetric content at least partly affects TB. However, because of the effect of snow on L-Band emission, the correlation between TB and εG decreased with snow accumulation. When compared to satellite measurements, the average TB of the seven plots were well correlated with the Soil Moisture Ocean Salinity (SMOS) TB with a root mean square difference of 8.1 K and consistent representation of the strong F/T signal (i.e., TB increases and decreases when soil freezing and thawing, respectively). This study allows better quantitative understanding of the spatial variability in L-Band emissions related to landscape F/T, and will help the calibration and validation of satellite-based F/T retrieval algorithms.

Evaluating the Relative Importance of Shallow Subsurface Flow in a Prairie Landscape

Core Ideas Contrary to established theories, vadose water contributes considerably to Canadian Prairie stormflow. Travel velocities of subsurface flow may exceed surface flow in some cases. Traqnsmissivity feedback and macropore flow promote “old” water deliveryto Prairie streams. Hydrologic literature on the Northern Great Plains, including the Canadian Prairies, has mainly focused on Hortonian overland flow as the dominant runoff generation mechanism. This study focused on subsurface water movement and its contribution to streamflow in high‐latitude, subhumid, prairie landscapes with flat topography. Three “riparian‐to‐stream” sites were monitored in southeastern Manitoba, Canada, and four hydrologic events (snowmelt triggered and rainfall triggered) were selected for analysis. A dual water sourcing strategy, including conservative and non‐conservative tracers, was applied to distinguish the relative importance of event (“new”) and pre‐event (“old”) runoff sources. Surrogate measures of antecedent wetness conditions (AWCs: based on rainfall, snow water equivalent, and soil saturation) data and streamflow and water table fluctuation data were used to identify factors influencing the contributions of different runoff sources. Results showed significant old water contributions during snowmelt‐ and rainfall‐triggered events, especially during the summer season. At an engineered grassland site, decreases in snow cover extent were accompanied by “flashy,” high‐magnitude stream hydrographs. Larger peak discharge was observed coincident to elevated AWCs at all sites. Travel velocities of surface‐applied dye were faster than those of subsurface‐applied dye, except for one rainfall‐triggered event. Rapid delivery of old water to streams was observed and hypothesized to be the result of macropore flow, piston flow, or transmissivity feedback depending on the season and water table position. Further investigations are recommended to increase our understanding of subsurface runoff generation mechanisms that promote the rapid movement of old water from riparian areas to streams in Canadian Prairie landscapes.

Doing more with less: Removing trees in a prairie system improves value of grasslands for obligate bird species

Grassland birds endemic to the Northern Great Plains have declined faster and more severely than any other avian guild on the continent. Remaining prairie fragments that sustain breeding populations are continually converted to a disturbed state, or degraded by fragmentation. Planted tree rows (shelterbelts) in prairie landscapes are a prominent feature and have been implicated in propagating negative edge effects on breeding birds, perhaps through harboring a diverse suite of nest predators. We experimentally removed shelterbelts on areas in the northern tallgrass prairie in North and South Dakota USA while conducting avian surveys to evaluate hypotheses about grassland bird response to the removal of a woodland edge. We predicted that 1) grassland-nesting species would avoid shelterbelt edges, 2) removing shelterbelts would eliminate avoidance, and 3) trends in bird counts would increase at sites with shelterbelts removed. Bobolink (Dolichonyx oryzivorus), Savannah Sparrow (Passerculus sandwichensis), and Sedge Wren (Cistothorus platensis) demonstrated avoidance from woodland edges up to 220 m, the farthest distance considered, though results for Grasshopper Sparrows (Ammodramus savannarum) were equivocal. There was no evidence of avoidance following removal of shelterbelts, and predicted counts increased at greater rates in treatment compared to control sites among species that exhibited avoidance. With limited financial resources for conservation, our findings support shelterbelt removal as one cost-effective management strategy to improve grassland bird habitat in the northern tallgrass prairie.

Uncertainty and the Entanglement of Habitat Loss and Fragmentation Effects in the Management of Northern Bobwhite

There is a need to understand the effects of habitat loss and fragmentation on northern bobwhite (Colinus virginianus) and other grassland bird species and relate this to conservation action and delivery, especially in areas of intensive anthropogenic development. Through our research, we investigated the factors contributing to habitat loss and fragmentation in order to prioritize management within the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC) region of Texas, USA. For this geographic region, we completed these objectives: analyzed grassland bird habitat loss and fragmentation resulting from oil and gas development, which has become especially rapid in this region beginning in 2008, projected future habitat loss under possible future economic scenarios, modeled the outcomes of potential management alternatives, and identified drivers of habitat loss and fragmentation to direct management action toward minimizing threats to high-risk habitats. Using a modeling approach, we identified suitable bobwhite habitat and prioritized high-risk areas, particularly focusing on the best candidate areas for successful restoration. Briefly, point count data were related to patch- and landscape-level habitat characteristics using a modeling technique that formally estimated the scale of the landscape effect on bobwhite abundance. Thereafter, we identified possible management alternatives with the guidance of the GCP LCC and other stakeholders and modeled the consequences of these alternatives. Using results from this modeling, we produced an extinction risk map for northern bobwhite in this region. Our research adds to the understanding of the relationship between northern bobwhite populations and the expansion of energy extraction and also uses modeling informed by data to support a decision-making framework that incorporates uncertainty about this system to prioritize the conservation of high-risk and high-value areas of bobwhite habitat.

A Method for Setting Northern Bobwhite Population and Habitat Objectives for Large Landscape Partnerships

Population and habitat objectives are the foundation for many conservation actions. Often objectives set at one scale are difficult to translate to larger or smaller scales. Three bird habitat Joint Ventures, Gulf Coast, Oaks & Prairies, and Rio Grande, working cooperatively with the Gulf Coast Prairie Landscape Conservation Cooperative, have a common objective to stabilize northern bobwhite (Colinus virginianus) populations in four Bird Conservation Regions. We cooperatively developed a method using the North American Breeding Bird Survey trend for several scenarios with different time horizons (10-, 20-, 30-year, or longer), the spring home range size, and the per acre cost of habitat management actions, to set spring population and habitat objectives and projected costs. The spring population objectives can easily be converted to fall population objectives using the percent summer gain. We provide an example of how three Joint Ventures could use this methodology to set bobwhite objectives within their geographies and then scale those objectives up to the next larger geography, a Landscape Conservation Cooperative geography. This methodology can be used by other multi-state partnerships (e.g., Joint Ventures and Landscape Conservation Cooperatives) across the bobwhite range to provide the bobwhite conservation community meaningful objectives at regional and national scales.

Impacts of Habitat Fragmentation on Northern Bobwhites in the Gulf Coast Prairie Landscape Conservation Cooperative

The northern bobwhite (Colinus virginianus) has experienced range wide declines over the last several decades, primarily due to loss and fragmentation of habitat. As populations decline, there is a need for understanding factors that impact bobwhite population persistence at local and regional spatial scales. Our goal was to assess changes in land use and their relationship to bobwhite declines at 3 different spatial scales (region, county, and home range) in Texas, Oklahoma, and Louisiana. We used North American Breeding Bird Survey (BBS) data from 1974-2014 to create abundance maps and trends. At the regional scale, we compared bobwhite abundance with road density (2000, 2010), human population (1970-2010), and land use (1974-2012). We then used the BBS data to identify counties with stable and declining bobwhite abundance, and then compared bobwhite abundance to land use at metapopulation (800-9600 ha) and home range scales (15 ha). Bobwhite populations decreased from 45.93 ± 1.01 birds/count in 1970 to 11.55 ± 0.64 birds/count in 2012. as road density and human population increased. Pasture and other land increased, woodland was relatively stable, and cropland decreased in 2012. At the metapopulation level, declining populations had higher road density, more edge and patch area for pasture, and larger patches of cropland compared to stable populations. At the home range scale, declining populations had significantly fewer, and smaller, woody patches, more herbaceous habitat, and less bare ground. This study demonstrates that while on a small scale managers can provide woody cover and reduce cropland effects to support stable populations, the large-scale drivers of bobwhite decline, namely human population growth and the resulting loss of habitat, will be critical to quail management in the future.

Fire Resilience of Aquatic Crustacean Resting Stages in Playa Wetlands, Oklahoma, USA

Prescribed burns and wildfires maintain prairie vegetation by limiting tree growth and promoting prairie grasses and forb production. Previous studies have shown that fire causes mixed effects on the prairie fauna, promoting some organisms while negatively affecting other organisms. Playa wetlands are interspersed within some semi-arid prairie landscapes, and are thereby subject to fire. These temporary wetlands can remain dry for years and less mobile aquatic taxa survive dry periods as drought resilient resting stages. We experimentally examined the effect of fire on the subsequent hatching of crustacean resting stages found in playa wetlands. Soil collected from four western Oklahoma playa wetlands was mixed and left unburned or exposed to burning (at three fuel levels: 0.5 time, 1 time, and 3 times the natural vegetation biomass) to simulate different fire intensities. We rehydrated soil taken from two depths (0 cm to 1 cm and 1 cm to 2 cm) for two weeks and examined hatched invertebrates and algal biomass. We did not find any significant difference in invertebrate richness and abundance or algal biomass from treated (burned) and untreated (unburned) soil in either of the soil layers. The resting stages of invertebrates are tolerant to a wide range of environmental factors and, consequently, are apparently tolerant (as a population) to increased soil temperatures resulting from low intensity burning.

The Saskatchewan Shelterbelt Inventory

Shelterbelts represent a significant carbon reserve on the agricultural prairie landscape, and knowledge of their extent can be of importance to atmospheric carbon mitigation strategies. We describ...

Carl J. Tracie, Shaping a World Already Made: Landscape and Poetry of the Canadian Prairies

It is a daunting task to write a study in a field that is not your own. In Shaping a World Already Made, Carl J. Tracie turns a geographer’s eye towards the poetry of the Canadian prairies. As he writes, his goal is “to recognize the importance of not only the scientific, the factual, the ‘real’ of prairie landscape, but also the imaginative and emotional, so that together they might express the full range of observations and reactions to this spare land” (124). To this end, he examines a num...

Effectiveness of vegetation buffers surrounding playa wetlands at contaminant and sediment amelioration

Playa wetlands, the dominant hydrological feature of the semi-arid U.S. High Plains providing critical ecosystem services, are being lost and degraded due to anthropogenic alterations of the short-grass prairie landscape. The primary process contributing to the loss of playas is filling of the wetland through accumulation of soil eroded and transported by precipitation from surrounding cultivated watersheds. We evaluated effectiveness of vegetative buffers surrounding playas in removing metals, nutrients, and dissolved/suspended sediments from precipitation runoff. Storm water runoff was collected at 10-m intervals in three buffer types (native grass, fallow cropland, and Conservation Reserve Program). Buffer type differed in plant composition, but not in maximum percent removal of contaminants. Within the initial 60 m from a cultivated field, vegetation buffers of all types removed >50% of all measured contaminants, including 83% of total suspended solids (TSS) and 58% of total dissolved solids (TDS). Buffers removed an average of 70% of P and 78% of N to reduce nutrients entering the playa. Mean maximum percent removal for metals ranged from 56% of Na to 87% of Cr. Maximum removal was typically at 50 m of buffer width. Measures of TSS were correlated with all measures of metals and nutrients except for N, which was correlated with TDS. Any buffer type with >80% vegetation cover and 30–60 m in width would maximize contaminant removal from precipitation runoff while ensuring that playas would continue to function hydrologically to provide ecosystem services. Watershed management to minimize erosion and creations of vegetation buffers could be economical and effective conservation tools for playa wetlands.

Temporal variability in aboveground plant biomass decreases as spatial variability increases

Ecological theory predicts that diversity decreases variability in ecosystem function. We predict that, at the landscape scale, spatial variability created by a mosaic of contrasting patches that differ in time since disturbance will decrease temporal variability in aboveground plant biomass. Using data from a multi-year study of seven grazed tallgrass prairie landscapes, each experimentally managed for one to eight patches, we show that increased spatial variability driven by spatially patchy fire and herbivory reduces temporal variability in aboveground plant biomass. This pattern is associated with statistical evidence for the portfolio effect and a positive relationship between temporal variability and functional group synchrony as predicted by metacommunity variability theory. As disturbance from fire and grazing interact to create a shifting mosaic of spatially heterogeneous patches within a landscape, temporal variability in aboveground plant biomass can be dampened. These results suggest that spatially heterogeneous disturbance regimes contribute to a portfolio of ecosystem functions provided by biodiversity, including wildlife habitat, fuel, and forage. We discuss how spatial patterns of disturbance drive variability within and among patches.

Soil Organic Carbon Dynamics in Eroding and Depositional Landscapes

As a requisite to determining management practice effects on stored soil organic carbon (SOC) stock in a landscape unit, the baseline SOC stock with depth must be determined and the land use, management practices and erosion-induced changes measured periodically or over a period of time. The SOC loss and additions due to soil erosion, transport and deposition must be accounted for or be quantified when determining the real impact of the management practices on net SOC stock over time. Quantifying the SOC loss due to erosion will help avoid over estimation of the management practice performances. Appropriate soil sampling designs and sampling procedures are needed to establish a SOC stock baseline and to monitor and verify new SOC storage or sequestration as a result of a management practice. The Dinesen Prairie landscape in western Iowa, USA was sampled to provide a SOC stock baseline and then the adjacent cropland was sampled to determine the past impact of land use change, management practices and erosion on SOC stock retention. After 100 to 150 years of farming, the entire cropland landscape retained only 49% of the baseline prairie SOC stock. Only the cropland toe-slope (TS) retained more SOC stock than the prairie TS as a result of the erosion, transport and deposition of SOC rich sediment on the TS.

New mapping techniques to estimate the preferential loss of small wetlands on prairie landscapes

AbstractReliable estimates of wetland loss require improved wetland inventories and effective monitoring programmes. The Prairie Pothole Region of North America is experiencing rapid urban, agricultural and economic development, which places wetlands at risk, especially small geographically isolated wetlands. This loss is concomitant with a loss of ecosystem services. To improve upon current wetland inventories, a method for mapping wetlands using an automated object‐based approach was developed for a regional watershed in Alberta. The method improves upon existing wetland mapping methods by effectively mapping small wetlands and better capturing the convolution of wetland edges. This approach uses digital terrain objects derived from light detection and ranging data, from which 130 157 wetlands were identified. Wetland loss estimates (% number and % area) were obtained by applying a wetland area versus frequency power‐law function to the wetland inventory. We estimated a 16.2% historic loss of wetland number and a 2.6% loss of wetland area, with the size of these lost wetlands <0.04 ha. The improved techniques for mapping wetland loss and estimating wetland loss provide a more accurate representation of the magnitude of wetland loss in the Prairie Pothole Region. Copyright © 2015 John Wiley & Sons, Ltd.

Spatiotemporal variability of water quality and stable water isotopes in intensively managed prairie watersheds

AbstractLow‐relief and highly engineered prairie landscapes present many challenges for water quality modelling. Limited investigation has been carried out to determine whether drains, canals and diversions (artificial waterways) impact water quality relative to natural or naturalized systems or to assess the value of stable water isotopes as predictor variables for specific water quality metrics. The goal of this paper is to investigate the spatiotemporal variability of water chemistry in a typical prairie watershed by (1) comparing water quality and stable water isotopic ratios between naturalized and artificial waterways; (2) evaluating the relationships between topographic and land use characteristics, water quality and stable water isotopic ratios; and (3) expressing and predicting PO4 concentrations as a function of stable water isotopic ratios. Focus was on the 2509 km2 mostly agricultural Seine River Watershed located in southern Manitoba, Canada. Twenty‐four sampling sites located along naturalized river reaches, drains and diversions were visited once a week from May to June 2013. Surface water samples were collected and tested for physical water quality parameters and PO4 concentrations, δ2H and δ18O. Kruskal–Wallis tests show no significant differences in water chemistry among waterway types, while strong correlations were found between physical water quality parameters, PO4 concentrations, isotopic ratios and watershed characteristics. PO4 concentrations were successfully predicted from isotopic ratios using linear regression models. These results bear significant importance for the mostly ungauged prairie watersheds, thanks to the relative ease and lower cost of measuring stable water isotopic ratios in comparison to nutrient concentrations. Copyright © 2015 John Wiley & Sons, Ltd.

Hybrid modelling approach to prairie hydrology: fusing data-driven and process-based hydrological models

Much of the prairie region in North America is characterized by relatively flat terrain with many depressions on the landscape. The hydrological response (runoff) is a combination of the conventional runoff from the contributing areas and the occasional overflow from the non-contributing areas (depressions). In this study, we promote the use of a hybrid modelling structure to predict runoff generation from prairie landscapes. More specifically, the Soil and Water Assessment Tool (SWAT) is fused with artificial neural networks (ANNs), so that SWAT and the ANN module deal with the contributing and non-contributing areas, respectively. A detailed experimental study is performed to select the best set of inputs, training algorithms and hidden neurons. The results obtained in this study suggest that the fusion of process-based and data-driven models can provide improved modelling capabilities for representing the highly nonlinear nature of the hydrological processes in prairie landscapes.Editor D. Koutsoyiannis; Associate editor L. See

Lukas Foss’s American Works as Expressions of the Immigrant Experience

Three overtly American works by German American immigrant composer Lukas Foss (The Prairie, American Cantata, and American Landscapes) offer insight into the musical expression of Foss’s immigrant experience, a motive for his compositional eclecticism that has not been previously considered. This immigrant experience can be understood as both a negotiation of multiple identities and an ambiguous relationship with the United States, and is expressed in music through text, preexistent melody, musical style, instrumentation, and other factors. The later works show Foss’s increasing acculturation through a greater facility with American vernacular music and an increasing willingness to directly criticize his adopted country.

Invasibility Drives Restoration of a Floodplain Plant Community

AbstractAn understanding of the processes that determine plant community structure is a requisite for the planning and evaluation of restoration efforts on river floodplains. Variable disturbance regimes derived from flood pulses increase the susceptibility of river floodplains to colonizations by new species and establish invasibility as a potentially important factor in plant community assembly and dynamics. The role of invasibility in the restoration of a wet prairie community on the Kissimmee River floodplain in central Florida was evaluated by quantifying temporal species turnover rates during wet and dry season sampling over a 12‐year pre‐restoration and post‐restoration period. Turnover rates increased with reestablishment of annual inundation regimes and were significantly greater on the reflooded floodplain than on the drained, channelized floodplain. Recurrent periods of increased invasibility were associated with repeated high‐amplitude flood pulses and accompanied by increased diversity of plant communities within the wet prairie landscape. Neither invasibility nor beta diversity was strongly related to the variable hydroperiods or depths provided by local topography and restoration of seasonal hydrologic regimes. Results suggest that invasibility is a functional process by which the restored flood pulse has reestablished the structure and diversity of the wet prairie. Copyright © 2014 John Wiley & Sons, Ltd.

Measurements of canopy interception and transpiration of openly-grown eastern redcedar in central Okalhoma

Eastern redcedar ( Juniperus virginiana L.) is rapidly encroaching and degrading native prairie and rangeland landscapes in the Great Plains of the U.S. Little is known concerning the impacts of increasing redcedar density and areal coverage on local and regional water budgets through transpiration ( T r ) and canopy interception ( C I ) of precipitation. Limited T r and C I studies have been conducted in dense stands of redcedar but results from these studies may not be applicable to redcedar growing in open environments. Four redcedar trees (two large, two small) were located in central Oklahoma to measure T r . Two limbs (one on the north face and one on the south face) on each of the large trees were instrumented with sapflux sensors to measure T r from August 2010 through mid-July 2012. Limb level T r was scaled to tree level T r using ratios of both leaf and bole areas. Whole tree T r was measured on two small redcedar trees from mid-May 2011 through mid-July 2012. Transpiration of the small redcedars was found to respond quickly to precipitation events, while the large redcedars did not. Redcedar T r was compared to that of native grasses. The large redcedars exhibited higher T r rates than native grasses while the small redcedars transpired at rates closely matching native grasses. Four different redcedars were instrumented to measure C I from October 2009 through mid-July of 2012. Redcedar canopies were found to intercept 100% of precipitation for events ? 2.4 mm. Redcedar canopies reduce annual precipitation received at the surface by about 33%, and as much as 39% in the western portion of the state. Significant canopy interception of precipitation, coupled with T r rates as large as or larger than native grasses and with year-round T r , suggests increases in redcedar density and areal coverage could affect local water resources (e.g. reducing infiltration, runoff, and ground water recharge rates).

A practical formulation of snow surface diffusion by wind for watershed‐scale applications

AbstractPrediction of snow drift is of importance for structure design and traffic management on snowy and windy prairie landscapes. The snow redistribution by wind is also regarded as one of the largest sources of error in hydrologic snowmelt models. In this study, a snow movement equation was generalized and customized for horizontal two‐dimensional watershed‐scale applications by incorporating snow transport, wind snow diffusion, and snow gravitational movement. Then, the snow surface diffusion process by wind turbulence was formulated in terms of the autocorrelation functions of the measurable wind velocity field using G.I. Taylor's theorem. However, analysis of the example wind data suggested a delta correlation in wind turbulent component that resulted from subtracting their moving average values from the original wind speed data. The dynamic model based on the proposed formulation was able to effectively reproduce the observed equilibrium snow profiles affected by wind drifting. A two‐dimensional model simulation using a 10 m digital elevation model in Muddy Gap, Wyoming was also presented for qualitative validation of the model in the watershed‐scale applications. Additionally, the theoretical extension for preferential snow accumulation process was presented in Appendix . These modeling results together with the observations on the prairie suggested the importance of the snow surface diffusion process in addition to the snow transport.

Towards an improved land surface scheme for prairie landscapes

The prairie region of Canada and the United States is characterized by millions of small depressions of glacial origin called prairie potholes. The transfer of surface runoff in this landscape is mainly through a “fill and spill” mechanism among neighboring potholes. While non-contributing areas, that is small internally drained basins, are common on this landscape, during wet periods these areas can become hydrologically connected to larger regional drainage systems. Accurate prediction of prairie surface runoff generation and streamflow thus requires realistic representation of the dynamic threshold-mediated nature of these contributing areas. This paper presents a new prairie surface runoff generation algorithm for land surface schemes and large scale hydrological models that conceptualizes a hydrologic unit as a combination of variable and interacting storage elements. The proposed surface runoff generation algorithm uses a probability density function to represent the spatial variation of pothole storages and assumes a unique relationship between storage and the fractional contributing area for runoff (and hence amount of direct runoff generated) within a grid cell. In this paper the parameters that define this relationship are obtained by calibration against streamflow. The model was compared to an existing hydrology-land surface scheme (HLSS) applied to a typical Canadian prairie catchment, the Assiniboine River. The existing configuration is based on the Canadian Land Surface Scheme (CLASS) and WATROF (a physically-based overland and interflow scheme). The new configuration consists of CLASS coupled with the new PDMROF model. Results showed that the proposed surface runoff generation algorithm performed better at simulating streamflow, and appears to capture the dynamic nature of contributing areas in an effective and parsimonious manner. A pilot evaluation based on 1 m LiDAR data from a small (10 km2) experimental area suggests that the shape of the modeled storage-contributing area relationship is broadly consistent with that inferred from terrain analysis, under certain simplifying assumptions. The direct identification of storage–runoff parameters from terrain analysis is an outstanding challenge, and a promising area for future research.