To assess the accuracy of the second-generation Prairie Agrometeorological Model (PAM2nd) as an agrometeorological model for spring wheat on the Canadian Prairies, a study was conducted to validate the model using field measurements. Results from model validation indicated soil moisture was being overestimated at most sites during the second half of the growing season, while soil moisture was underestimated during periods that experienced consecutive days of rainfall. Modifications to the model were implemented to improve the model's ability to simulate soil moisture. Evapotranspiration estimates from PAM2nd and the FAO56 Penmen-Monteith method were compared to water balance methods. Both models produced estimates that fell within the range of water balance ET measurement error. The similarity in performance of both models to estimate ET compared to the water balance ET means the adoption of either model could be justified. However, PAM2nd would be more appropriate because it requires fewer, more commonly measured, surface weather parameters.

Thesis (M.S. in Soil Science)--Washington State University. / Includes bibliographical references.

Designed for the protection of major agricultural crops, neonicotinoids are the fastest-growing class of insecticides used against a broad spectrum of insect pests. Although neonicotinoid toxicity toward non-target organisms (e.g., bees, aquatic insects) has been well-studied, less is known about their distribution of use, transport, and fate in North American agroecosystems. This is especially true of neonicotinoid interactions with wetlands in the Canadian Prairies. Between 2009 and 2012, neonicotinoid use as a seed treatment increased by 30% across the Canadian Prairies. During spring 2012 to spring 2013, I sampled water and sediment from 136 wetlands situated in a range of crop types across central Saskatchewan to determine the extent of neonicotinoid contamination. Wetlands situated in oat, canola, and barley fields consistently contained higher neonicotinoid concentrations in water than in grasslands, but no single crop influenced overall detections. Neonicotinoid detections in water varied from 16% (fall 2012) to 91% (spring 2013) with peak concentrations up to 3110 ng/L found in summer. I found numerous detections of neonicotinoids in spring, after ice-off, but before seeding. Through sampling snow, snow meltwater, and soil particulates from previously treated (clothianidin) and untreated fields, meltwater showed the strongest relationship to initial spring concentrations in wetland water. Neonicotinoid concentrations increased with time in shallow temporary wetlands which appeared most at risk for annual contamination. While snowmelt contamination influenced water concentrations in spring, peak concentrations in wetlands were consistently found during summer sampling completed in 2012-2014. Rapid wetland assessments completed on 238 wetlands (summer of 2012 and 2013) revealed key ecological, hydrological and landscape features that influenced neonicotinoid detections and peak concentrations in Prairie wetlands. The results of my exploratory analysis indicated that plant community composition is a key indicator and/or driver of both detection and concentration of neonicotinoids in Prairie wetlands. In particular, specific shallow marsh plants were commonly associated with either higher (e.g., Scirpus validus) or lower (e.g., Mentha arvensis) neonicotinoid concentrations in natural wetlands suggesting wetland macrophytes in this zone may be either indicators of agricultural disturbance intensity or differentially capable of accumulating the insecticide in its tissue. Therefore, in 2014, I conducted an outdoor microcosm experiment to evaluate thiamethoxam uptake from water by Typha latifolia and Alisma triviale using two concentrations over a 7-day period. Experimental results found some trace positive detections but no quantifiable accumulation of the insecticide in plant tissues. This is despite the fact that results of my 2015 field study found species of Typha, Alisma and Equisetum had neonicotinoids more frequently detected in their tissues, at concentrations ranging from 1.01-8.44 ug/kg. My findings demonstrate that neonicotinoid distribution and fate in Canadian Prairie agroecosystems is driven by interactions between ecological, hydrological, and landscape characteristics. Consequently, these drivers regulate neonicotinoid exposure and persistence in ecologically important regional wetlands. In order to effectively conserve these critical waterbodies, conservation planning should consider the importance of maintaining naturally diverse vegetation zones to mitigate insecticide exposure to wetland-dependant organisms.

To determine how Pacific Northwest prairies are influenced by local site factors versus. regional climate, we studied the reproduction, plant size, and density of sixteen natural populations of four perennial forb species native to Pacific Northwest prairies: Ranunculus austro-oreganus, Sidalcea malviflora spp. virgata, Microseris laciniata, and Eriophyllum lanatum. These populations were distributed along a 700 kilometer latitudinal gradient from southern Oregon to Whidbey Island, Washington. We found significant differences in plant size and reproduction among populations for all species, but correlations among edaphic and climate variables and plant size and reproduction were weak. Instead, density was more strongly correlated with both edaphic and climate variables, suggesting that this is a better indicator of long-term demographic processes. Although a few factors are important across species (e.g., nutrient availability and minimum temperature), response is idiosyncratic at the individual species level in Pacific Northwest prairies.

No description available.

This study was initiated to secure quantitative data on growth characteristics of the major species in the mixed grass prairie of western North Dakota; to determine the extent and range in yearly variations in growth patterns of the species and of the type as a whole; to assess the general influence of climate as a cause for seasonal and yearly variations in growth patterns; and to interpret the data obtained in terms of their possible application to the practical grazing management of these grasslands. / This project was supported by the North Dakota Agricultural Experiment Station as a part of project Hatch 9-5: "Native range plants -- their growth and development in relation to the establishment of standards for their proper utilization."

The objective of this research was to assess the potential effects of global warming on the hydrology and vegetation in semi-permanent wetlands located in the glaciated prairie region of North Dakota. As a means to that objective, a spatially-defined simulation model of the vegetation dynamics in these wetlands was constructed. A hydrologic component of the model estimated water levels based on precipitation, runoff, potential evaporation and transpiration. Amount and distribution of emergent cover and open water were modeled using a geographical information system. Vegetation response to changes in water level was based on seed bank composition, seedling recruitment, establishment and plant survivorship. Simulation results were compared to actual distributions from aerial photographs (1979-89). Results showed that the model was relatively good at calculating changes in water level for average years. Late-summer water levels were overestimated during dry years due to limitations in the Thornthwaite method of calculating potential evapotranspiration. In general, changes in the ratio of emergent cover to open water were accurately simulated. Tests of the model elucidated two areas that needed improvement. First, seedlings germinated too quickly on exposed mudflats in the model when drawdown occurred late in the season. The actual wetland had a thick mat of dried, submergent vegetation on top of the mudflats which impeded germination, which the model did not consider. Second, model conversions between open water and deep marsh vegetation were not always timed correctly. If water depth crossed a threshold value for a given period of time a cell would change its type. In reality, tolerance of emergents to deep water is more complex. A probability function with respect to time and water depth rather than a threshold value would better represent this relationship. The model was used to assess the potential effects of global warming on the cover cycle in one wetland. An 11-year simulation was run using a normal versus greenhouse climate. Although water level fluctuations still occurred, peak values were significantly lower in the warming scenario and the wetland dried in most years. Simulations also revealed a significant change in the vegetation, from a nearly balanced cover ratio to a completely closed basin with no open water areas. / Ph. D.

Depuis le 19e siècle, des cultivars de peupliers à composantes exotiques comprenant les espèces Populus laurifolia Ledeb. et P. nigra L. coexistent avec les populations indigènes de P. balsamifera L. dans les Prairies canadiennes. Étant donné la facilité avec laquelle les peupliers s'entrecroisent, les taux d'hybridation spontanée entre un cultivar communément distribué [Symbole mâle]'Assiniboine' et son congénère indigène P. balsamifera ont été estimés. Un ensemble de 26 marqueurs moléculaires SNP a été utilisé afin de distinguer les espèces à l'étude. Le génotypage de plus de 2 000 graines provenant d'arbres femelles P. balsamifera a révélé la présence d'allèles paternels spécifiques à P. laurifolia, P. nigra et P. deltoides Marsh., qui sont des composantes typiques des cultivars de peupliers exotiques. Les taux d'hybridation varient entre 0,1 et 2,4 %. Le taux le plus élevé ayant été observé au site où des 'Peupliers russes' (P. laurifolia x P. nigra) centenaires ont été trouvés.

Cette étude visait à déterminer quelle devise nutritionnelle, parmi les gains journaliers en énergie digestible, les gains instantanés en énergie digestible, en phosphore ou en sodium, expliquait le mieux la répartition du bison (Bison bison) dans les prairies canadiennes. Nous avons caractérisé la sélection de l'habitat des bisons du parc national du Canada des Prairies à l'hiver et au printemps 2007 et interprété cette sélection dans le contexte des gains attendus pour chacune des quatre devises. En toutes saisons, les communautés végétales fournissant les gains instantanés les plus rapides en énergie digestible étaient les plus fortement sélectionnées. Cette sélection s'effectuait au détriment des autres devises. Ces résultats viennent appuyer des observations obtenues dans des écosystèmes boréaux. La recherche de gains rapides en énergie constitue donc un des mécanismes prépondérants de la répartition du bison, et du coup, cette devise devrait permettre d'anticiper sa répartition malgré des changements dans les écosystèmes.

The site analysis and mapping methods in the design and planning professions follow a standardized quantitative and qualitative analyis of place that favors a design process which can limit creativity and render it difficult to do anything with the normative. This work is an exploration of the development of a design approach and method that uses voice mapping as a basis for design. The voice maps contain oral histories and personal accounts of landscape experiences. Voice mapping is employed not only as a method or for site analysis but also as a generator or ideas. Voice Map Trekking is explored through a trek in the Canadian Arctic and across the Canadian Prairies. Two specific landscapes were chosen as bases for testing concepts - one near St. Gertrude SK and the other near Morinville AB. / February 2008