La violette birds-foot (Viola pedata) est une plante herbacée qui occupe les milieux ouverts, perturbés, bien drainés et à sols sableux de l'Est de l'Amérique du Nord. Au Canada, où cette espèce est désignée «en voie de disparition», toutes ses populations se retrouvent uniquement dans le sud de l'Ontario dans des habitats extrêmement rares, les prairies à hautes herbes et/ou savanes de chênes. Les objectifs de cette étude étaient de déterminer les exigences de microhabitat optimales permettant à Viola pedata de survivre, fleurir et produire des graines, ainsi que de fournir des valeurs seuil pour recommander des brûlages dirigés ou d'autres formes d'aménagement. Des données détaillées d'habitat, en particulier la quantité de lumière disponible sous le couvert des arbres, les espèces associées, les caractéristiques du sol et le recouvrement de différents types de litière, ont été récoltées dans 180 microquadrats localisés dans quatre populations de Viola pedata en Ontario. Ces données ont été utilisées pour évaluer trois catégories de conditions d'habitat de Viola pedata (microquadrats avec Viola pedata; microquadrats sans Viola pedata, mais à proximité de microquadrats avec Viola pedata; microquadrats sans Viola pedata, mais très éloignés de microquadrats avec Viola pedata) dans un site récemment brûlé et dans trois sites non brûlés. Des analyses de régression indiquent que le nombre de feuilles produites par les plants de Viola pedata est corrélé positivement avec le pourcentage d'ouverture du couvert arborescent. L'analyse canonique des correspondances révèle que les microquadrats qui contiennent Viola pedata sont associés à un pourcentage de sol à nu plus élevé. La perturbation par le feu produit une augmentation du nombre de fleurs et de la vigueur des plants de Viola pedata, ainsi qu'une augmentation des probabilités de germination des graines suite à la réduction de la quantité de litière. Les analyses ont déterminé que les facteurs écologiques les plus importants affectant Viola pedata, sur tous les sites, étaient le pourcentage d'ouverture du couvert arborescent et de sol à nu. L'ouverture du couvert arborescent affecte directement la survie, la vigueur et la production de fleurs, alors que le sol à nu affecte la régénération et la germination en réduisant la compétition. De ces analyses, il ressort qu'une valeur seuil d'au moins 15 pourcent d'ouverture du couvert arborescent est requis pour assurer la survie d'individus reproducteurs de Viola pedata dans le sud de l'Ontario. Les résultats de cette étude seront utilisés pour développer des critères d'aménagement pour la conservation de Viola pedata au Canada. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Viola pedata, Plante menacée, Habitat, Vestiges de prairie, Conservation.

Heterogeneity, the degree of dissimilarity, is one of the most important and widely applicable concepts in ecology. It is highly related to ecosystem conditions and features wildlife habitat. Grasslands have been described as inherently heterogeneous because their composition and productivity are highly variable across multiple scales. Therefore, biological heterogeneity can be an indicator of ecosystem health. The mixed prairie in Canada, characterized by its semiarid environment, sparse canopy, and plant litter, offers a challenging region for environmental research using remote sensing techniques. This thesis dwells with the plant canopy heterogeneity of the mixed prairie ecosystem in the Grasslands National Park (GNP) and surrounding pastures by combining field biological parameters (e.g., grass cover, leaf area index, and biomass), field collected hyperspectral data, and hierarchical resolution satellite imagery. The thesis scrutinized four aspects of heterogeneity study: the importance of scale in grassland research, relationships between biological parameters and remotely collected data, methodology of measuring biological heterogeneity, and the influence of climatic variation on grasslands biological heterogeneity. First, the importance of scale is examined by applying the semivariogram analysis on field collected hyperspectral and biophysical data. Results indicate that 15 - 20 m should be the appropriate resolution when variations of biological parameters and canopy reflectance are sampled. Therefore, it is reasonable to use RADARSAT-1, Landsat TM, and SPOT images, whose resolutions are around 20 m, to assess the variation of biological heterogeneity. Second, the efficiency of vegetation indices derived from SPOT 4 and Landsat 5 TM images in monitoring the northern mixed prairie health was examined using Pearsons correlation and stepwise regression analyses. Results show that the spectral curve of the grass canopy is similar to that of the bare soil with lower reflectance at each band. Therefore, vegetation indices are not necessarily better than reflectance at green and red wavelength regions in extracting biological information. Two new indices, combining reflectance from red and mid infrared wavelength regions, are proposed to measure biological parameters in the northern mixed prairie. Third, texture analysis was applied to quantify the biological variation in the grasslands. The textural parameters of RADARSAT imagery correlated highly with standard deviation of the field collected canopy parameters. Therefore, textural parameters can be applied to study the variations within the mixed prairie. Finally, the impacts of climatic variation on grassland heterogeneity at a long time scale were evaluated using Advanced Very High Resolution Radiometer (AVHRR) , Normalized Difference Vegetation Index (NDVI), Maximum Value Composite (MVC), and SPOT Vegetation NDVI MVC imagery from 1993 to 2004. A drought index based on precipitation data was used to represent soil moisture for the study area. It was found that changes of temperature and precipitation explain about 50% of the variation in AVHRR NDVI (i.e., temporal heterogeneity) of the northern mixed prairie. Trend line analysis indicates that the removal of grazing cattle carry multiple influences such as decreasing NDVI in some parts of the upland and valley grassland and increasing NDVI in the valley grassland. Results from this thesis are relevant for park management by adjusting grassland management strategies and monitoring the changes in community sizes. The other output of the thesis is furthering the remote sensing investigation of the mixed prairie based on information of the most appropriate resolution imagery.

The experience of wilderness and of homesteading on the prairies provided the primary subject matter for Canadian prairie fiction in the final decades of the nineteenth century and the first decades of the twentieth century. My thesis uses ecocriticism to make a connection between the cultural values embedded in this literature and the ecological consequences of European settlement. It uses the philosophical concepts of bioregionalism, deep ecology and ecofeminism as the ideological framework for a study of novels and short stories published prior to 1930. It uses the theoretical concepts of cultural materialism to analyze, from a socio-ecological perspective, the power relationships within this body of literature. More specifically, it looks at the way in which English-speaking writers privileged the values of civilization above wildness and the values of western European culture above the cultures of Metis and indigenous peoples. My thesis divides early prairie fiction into the categories of wilderness romance and homesteading romance. It looks at representative samples of these genres, and concludes by discussing two examples of early prairie realism. Throughout the entire thesis I view the fictional treatment of European settlement from the perspective of current ecological thinking and, in doing so, provide a critique of both past and present attitudes to the prairie environment.<p> The introduction provides a philosophical and critical approach to my study of literature and of its historical context. It traces the anthropocentric values of "old world" immigrants to the dominant ideology that developed in post-Medieval Europe: the Western Judaeo-Christian worldview of dominion over Nature, the faith in science and technology, and the materialist ideals of capitalism and economic progress. It considers the role that prairie fiction played in creating the cultural values that led to the modification of the natural prairie landscape, and explores the potential of critical theory to provide oppositional interpretations of the European settlement story. It then discusses the philosophical and theoretical framework of the ecocriticism that I use in my study of the interface between immigrant settlers, aboriginal people and the land.<p> Chapter One introduces the wilderness romance. It defines the terms which I use to describe immigrant, aboriginal and mixed-blood peoples. It points out that the transcendent nature of the romance makes it an ideal form for a body of literature that privileges civilization above wildness and culture above Nature. It shows how the quest structure of the wilderness romance endorses the values of Western civilization, and uses a legend from one of these romances in order to illustrate the way in which they empower the dominant culture. Chapter One concludes by showing how the English-language definitions of "wild" and "civilized" work to elevate the culture of "old world" immigrants above the traditions of a semi-nomadic wilderness people.<p> Chapter Two looks at the ambivalence to wildness apparent in two examples of the wilderness romance: R. M. Ballantyne's The Young Fur Traders, or Snowflakes and Sunbeams: A Tale of the Far North (1856) and William F. Butler's Red Cloud: A Tale of the Great Prairie (1882). It discusses both authors' use of Edenic imagery in their descriptions of the great Northwest, their differing views of aboriginal people and their pragmatic conclusions to the heroes' wilderness quest. It examines the implications of the protagonists' return to a prosperous, mercantile civilization, and points out that Ballantyne and Butler failed to recognize the incompatibility of their simultaneous images of the West as pristine wilderness and future home of a flourishing industrial economy.<p> Chapter Three looks at the civilizing impact of Victorian Christianity in two examples of missionary fiction: R. M. Ballantyne's The Prairie Chief: A Tale (1886) and Egerton Ryerson Young's Oowikapun or How the Gospel Reached the Nelson River Indians (1896). It suggests that both novels privilege civilization above wildness by equating Christianity with the order and domestic virtue of Victorian culture and by equating native spirituality with untamed Nature. Since Christianity was an unquestioned good in the Victorian hegemony, and native spirituality a threat to Christian dominance, the values of civilization basked in the reflected virtue of Anglo-Protestant ideology while wilderness and Nature were tarnished by their association with pagan superstition and evil. Chapter Three shows how the successful achievement of the heroes' wilderness quests involves bringing the light of Christian civilization to the darkness of the heathen wilderness.<p> Chapter Four examines the process of cultural genocide in two fur trade novels. It looks at the way in which Agnes Laut uses the captivity narrative in Lords of the North (1900) to illustrate the savage behavior of the uncivilized Indian, and the way in which Hulbert Footner uses the adventure story in The Fur Bringers: A Story of the Canadian Northwest (1920) to portray native and mixed-blood people as either wicked and cunning or naive, childlike and dependent. It shows how the authors attempt to invalidate the traditional culture of a wilderness people by comparing its apparent weaknesses with the stronger, morally superior culture of their white protagonists. Both novels thus validate the obliteration of aboriginal traditions and their replacement by the values and institutions of Western civilization.<p>Chapter Five uses three novels to explore the way in which romance writers used stories of native "rebellion" to justify the suppression of political resistance. Joseph Collins, an ardent Canadian nationalist, wrote Louis Riel The Rebel Chief (1885) to inflame Eastern opinion against the Metis "rebels" who threatened to destroy his vision of a strong and united nation; this chapter looks at his use of historical misrepresentation, inflammatory language and tragic melodrama to discredit the "barbarian" forces that threatened imperial law and order. Ralph Connor's later account of an abortive 1885 Indian uprising, in Corporal Cameron (1912) and The Patrol of the Sun Dance Trail (1914), is more sympathetic towards native people but it, too, privileges white civilization by equating the interests of immigrant ' settlers with the public good. By further associating the Indian and Metis "rebels" with the disorder and chaos of wild Nature, Collins and Connor helped to invalidate native resistance and to ensure Anglo-Canadian victory over the degraded "savages."<p> Chapter Six looks at the connection between patriarchal power and the "old world" social order in Harwood Steele's Mounted Police romance, Spirit-of-Iron (1923). It shows how Steele privileges civilization above wildness by glorifying a para-military hierarchy based upon "masculine" strength and adherence to the values of Empire. Power accrues in Steele's novel to men whose fists and nerve and endurance enable them to enforce their will on women and Nature and weaker men. Chapter Six looks at the way in which this power hierarchy helped to convert an unproductive wilderness into a prosperous British colony, and reveals the enormous costs that women unwittingly pay for the privilege of supporting key (masculine) players in the drive towards "progress."<p> Chapter Seven explores the connection between patriarchal man's dominance of woman and Nature in Douglas Durkin's The Heart of Cherry McBain (1919) and The Lob stick Trail (1921). It illustrates the symbiotic relationship between male dominance and economic progress in the building of two important patriarchal institutions--the railway and the mining industry. Durkin's novels cast a romantic glow over the men who risked life and capital to build roadbeds and to develop the mineral resources of the Northwest; Chapter Seven, however, shows how the rules which govern this development empower men at the expense of women and Nature, and reveals the high human and ecological costs of denying integrity to both the feminine and the natural world.<p> Chapter Eight introduces the homesteading romance. It notes the conflicting impulses behind popular images of the West as pastoral utopia: the settler wants to create both an arcadian garden in the wilderness and a prosperous outpost of a mercantile civilization. It discusses the philosophical origins of the industrial market economy, and looks at the social, economic and ecological costs of commercial, export-oriented agriculture on the Canadian prairies. Chapter Eight notes the absence of indigenous and mixed-blood people in the homesteading romance, and discusses the unrealized potential of traditional Metis culture to provide immigrants with an ecologically appropriate response to the "new world". It discusses one French-Canadian novel, Georges Bugnet's Nipsya (1924; trans. 1929), which provides the only significant study of Metis culture in early prairie fiction.<p> Chapter Nine looks at two novels which served as homesteading manuals for would-be immigrants. Both Alexander Begg's "Dot It Down;" A Story of Life in the North-West (1871) and W. H. P. Jarvis's The Letters of a Remittance Man to His Mother (1908) provide advice on farming for profit. Chapter Nine looks at the development of export agriculture on the prairies, and considers the role that Begg's and Jarvis's novels played in promoting high production and prosperity as the goals of farming. It points out that neither novel considers the economic climate created by a national policy which privileged business interests above the interests of farming, and concludes that they are therefore not only flawed guides to the development of sustainable agriculture but also unrealistic proponents of a materialist utopia.<p> Chapter Ten looks at the contribution of two English novelists to the anthropocentric ideal of mastering wild Nature. Harold Bindloss's and Mrs. Humphrey Ward's prairie fiction portray strong, virile man who carve farms from the wilderness and transform "wasteland" into wheatfields. Guided by a dream of dominion over the natural world, they are rewarded both by wealth and by marriage to well-born English maidens. Bindloss and Ward celebrate the heroism of the stalwart men whose agricultural victories provide prosperity for the Canadian North West and bread for the people of England; Chapter Ten, however, traces the cultural roots of current environmental problems to anthropocentric values such as those embedded in their novels.<p> Chapter Eleven examines the part that literature played in integrating "foreign" immigrants into an essentially British society. It looks at the process of assimilation in four prairie novels: Ralph Connor's The Foreigner: A Tale of Saskatchewan (1909), Flos Jewell Williams's New Furrows: A Story of the Alberta Foothills (1926), Eric Gill's Love in Manitoba (1911) and Laura Goodman Salverson's The Viking Heart (1923). These novels equate becoming a good Canadian with adoption of the mercantile ideals of economic progress and with rejection of the peasant ideals of self-sufficiency. As Chapter Eleven points out, they helped to obliterate the values of an "old world" peasantry which viewed land as sacred and simultaneously strengthened the Western imperative of human dominion over Nature.<p> Chapter Twelve discusses the industrialization of agriculture in Robert Stead's Grain (1926). It points out that although Stead was critical of the greed and materialism that accompanied Western settlement, his novels reflect the anthropocentrism endemic to early prairie fiction. It looks at Stead's treatment of the homesteader's "sacred" mission to subdue the earth. It examines the historical context in which Grain is situated, and it discusses Stead's ambivalent--although ultimately favourable--response to the phenomenon of farm mechanization.<p> Chapter Thirteen contrasts Western man's quest for wealth and power with woman's oppositional quest for healing community. Using Martha Ostenso's Wild Geese (1925), Arthur Stringer's Prairie trilogy (1915-22) and representative fiction of Nellie McClung (1908-25) as texts, it explores the way in which these writers privilege nurturing relationships above the exploitative relationships that characterize prairie agriculture. Stringer's heroine condemns her husband's obsession with money and power, and proposes an alternative ideology based upon love of family and home. Ostenso's Judith Gare rebels against patriarchal tyranny. McClung's protagonists serve as compassionate caregivers who view the land as a resource that provides sustenance--not wealth--for its human inhabitants. In their common opposition to an androcentric culture based on power over women and the land, these novels portray the feminine quest for healing community and for harmony between humans and their prairie home.<p> Chapter Fourteen looks at two examples of early prairie realism--Frederick Philip Grove's Settlers of the Marsh (1925) and Our Daily Bread (1928). It discusses Grove's love for the prairie landscape, his admiration for the self-sufficient man of the soil, his distaste for economic ambition and his tragic view of life. It contrasts the tragic realism of Our Daily Bread with the comic spirit of reconciliation in Settlers of the Marsh, and suggests that the latter proves better adapted than tragedy as a form in which to cast the heroes' quest for nurturing community. <p>The Conclusion examines the role of the critic as social prophet and revisionary historian. It discusses the role of myth in influencing the course of history, summarizes the cultural impact of the myth of progress created by the wilderness and homesteading romance, notes the existence--and importance--of an oppositional quest for a harmonious relationship with the land, and reviews the role of bioregionalism, deep ecology and ecofeminism in providing the philosophical basis for a sustainable culture appropriate to the prairie bioregion. It considers the responsibility of both homesteaders and turn-of-the-century business entrepreneurs for current environmental degradation, and concludes that the dominant interests of urban politicians, consumers and business people have always been the impetus to agricultural expansion and the continuing depletion of prairie soils.

Lesser prairie chicken (Tympanuchus pallidicinctus) numbers have declined considerably in Texas since the early 1900s. Conversion of native prairie to cropland has been the major cause of the decline. I trapped and monitored 115 (66 males, 49 females) lesser prairie chickens in the Rolling Plains of the Texas Panhandle from 2001 through 2003. I used an information-theoretic approach to model selection as implemented in program MARK to evaluate factors contributing to variation in survival and differences in nest success. I found breeding season survival of both males and females was lower compared to non-breeding season survival. Annual survival was 0.52 (95% CI: 0.32? 0.71). Model selection indicated higher nest success (70%) in the sand sagebrush (Artemisia filifolia) vegetation type as compared to the shinnery oak (Quercus harvardii) type (40%). I also evaluated post-burn habitat alterations and plant succession (1 year and 2 years after burning) as potential lesser prairie chicken habitat. After spring rainfalls stimulated re-growth of herbaceous plants, male lesser prairie chickens moved to the site, feeding on new-emerging forbs throughout the summer. A female lesser prairie chicken with a brood used the burned site during the first summer after the burn. A year later, males established a lek on the burned site. Two female lesser prairie chickens with broods used the burned site during the second summer. Burned sites had more forbs than nonburned sites and probably had more insects available which are an important food source for chicks during their first 4?5 weeks of age.

The prairies of North America have undergone substantial changes since European settlement in the 1800's, with some estimates suggesting that 96% of the tallgrass prairie has been converted. Multiple factors contributed to reduction in prairie, including: grazing, row-crop farming, depressed fire regimes, and exotic grass species introduction. In Texas, 35% of the historic grassland ecosystems have been either altered or converted. Introduced in the 1940's, exotic grass species such as Bermuda grass (Cynodon sp) have displaced native grass species throughout Texas. Introduced grass species can alter the existing plant communities degrading habitat for birds and other animals. Grassland birds are declining faster than any other bird group within North America; due in part to a reduction in suitable breeding habitat. I addressed this issue by comparing nesting success of grassland birds between exotic grass sites and restored native grass sites in the blackland prairie region of east-central Texas during 2007-2008 breeding seasons. I conducted point counts and nest searching from March - July. Point count data indicate no difference in species richness between sites. Dickcissel (Spiza americana) nests represented 89% of the nests found (n = 104). Dickcissel abundance was 44% higher in restored sites and 76% of nests were located in restored sites. Daily survival (DSR) for dickcissels in restored sites was 0.895 (SE = 0.013) and for exotic sites was 0.930 (SE = 0.017). I used an independent samples t-test to compare mean nest height, which was 56% higher in restored sites than exotic sites (n = 83, x bar = 38.0 cm plus/minus 1.90; x bar = 15.2 cm plus/minus 2.19, df = 81, t = -6.31, P = 0.001), and mean nest substrate height which was 58% higher in restored sites than in exotic sites (n = 83, x bar = 118.8 cm plus/minus 6.50; x bar = 46.5 cm plus/minus 4.77, df = 81, t = -6.08, P = 0.001). Although dickcissel abundance was greater in restored sites than exotic sites, their observed nesting success and DSR was lower in restored sites. This is indicative of an ecological trap, which occurs when an organism is attracted to a habitat that negatively impacts the organism. Some research suggests that restored fields in other states are acting as traps for dickcissels, and according to my results restored sites I sampled may also be acting as ecological traps for dickcissels in Texas.

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Zuoxin Wang, Florida State University, College of Arts and Sciences, Dept. of Psychology. Title and description from dissertation home page (viewed Oct. 1, 2003). Includes bibliographical references.

Since the major influx of settlement in the 19th century, architecture on the Saskatchewan prairie has focused on imported types and products, a condition that has contributed to the lack of a clear regional architectural identity. This architectural thesis explores fundamental characteristics of inhabiting the prairie in order to create designs that are better adapted to its physical and cultural context. Investigations deal with the horizon-based experience, exposure, extreme temperatures, and the relationships between brought and found elements. The architectural implications of these characteristics are tested within the context of an overarching narrative of the socioeconomic and architectural forces at work behind contemporary projects in the region: A generic town and fictitious inhabitants are created to help the designs respond to common realities and challenges facing the prairie today. Based on these investigations, improvements are proposed for several major building types, including a house, duplex, rink, church, and school.

To manage underused urban grassy spaces like transmission lines as tall-grass prairie habitats or other endangered ecosystems, ecologists need to know how mowing, spraying and surrounding urban lands affect species richness and numbers of plants and animals along transmission lines. I conducted surveys along 48 transmission lines in Winnipeg, Manitoba in 2007-2009 to answer these questions, and I concluded that mowing and spraying should be reduced, but not eliminated, to increase butterflies and other arthropods, resources for butterflies and other arthropods, and arthropod prey for birds. However, the amount of nearby urban land reduced plant species richness and grassland bird abundance along lines more strongly than mowing or spraying, suggesting that lines with less nearby urban land should be selected for management as grassland bird habitats. Mowing and spraying can then be reduced along these lines to benefit other species, enabling urban lands like transmission lines to contribute to conservation.

Avian point counts were conducted in tall-grass prairie fragments and adjacent grassland and agricultural matrix habitat in southern Manitoba. Bird density/abundance was compared between habitat types, while variables within prairie at local, patch or landscape level were modeled to determin avian habitat selection. Prairies and matrix grassland habitat supported the same number of species in both years, and densities of all focal bird species were the same in non-native grasslands as compared with native tall-grass prairies. Overall species richness in tall-grass prairies was mainly driven by vegetation variables. Variable responses to habitat structure and composition between avian species indicate that managing grasslands to promote heterogeneity is important to sustain a diverse assemblage of avian species. As individual species were affected most strongly by vegetation structure and richness, it follows that management of prairie vegetation through techniques such as grazing and prescribed burning could optimize habitat usability for birds.

The Yellow Quill Mixed Grass Prairie Preserve is a remnant of an endangered community that is located in southwestern Manitoba and owned by The Nature Conservancy of Canada. In 2005 and 2006, this study was conducted to investigate the effect that the currently-practiced twice-over rotational cattle grazing regime is having on the carabid beetles and spiders. This study primarily compared grazed and ungrazed treatments on three paddocks. A secondary experiment investigated whether the spring graze, fall graze, or the combination of the two had the greatest impact on the carabids and spiders. Three periods were examined in three periods each season: before grazing had begun, after the spring graze, and after the fall graze. A total of 81 species of carabids and 156 species of spiders were recorded, including potentially new provincial records (two carabid species and 20 spider species). Seventy two species of plants were recorded in the study.