Grassland bird species have declined dramatically since 1966. This decline can be linked to changes in land use practices, such as grazing. I examined the effects of cattle grazing on the abundance of birds by testing the predictions of the More Individuals Hypothesis (MIH). The study was conducted in Grasslands National Park of Canada (GNPC) in Saskatchewan. Point counts were used to sample richness and relative abundance of birds. I sampled two groups of invertebrates: grasshoppers and carabid beetles. In addition, vegetation measurements were taken to assess the intensity of grazing. I found that (1) grasshopper abundance, richness and diversity were higher in grazed pastures; (2) carabids showed mixed responses to grazing; (3) bird abundance was correlated with carabid abundance, thus supporting the assumptions of the MIH. Overall, my results indicate that grazing can be beneficial for both birds and their invertebrate prey in southern Saskatchewan mixed-grass prairies.

Microhistological analysis is a highly effective microscopic technique of determining botanical composition of animal diets by visual recognition of fecal plant fragments, and has been widely used in range studies. The objective of this study was to use microhistological techniques to predict the botanical composition of domesticated horse diets when grazing mixed cool-season pasture. Samples of tall fescue [Lolium arundinaceum (Schreb.) S.J. Darbyshire], Kentucky bluegrass (Poa pratensis L.) and orchardgrass (Dactylis glomerata L.) were evaluated for microscopically unique characteristics. Cool season pasture grazing studies were conducted in October 2006 and May 2007 in Lexington, KY. Eight thoroughbred mares were placed in individual paddocks of varying botanical compositions to graze for six days. For each percent increase of tall fescue or orchardgrass in the paddock, there was a corresponding increase of 0.44% and 0.42%, respectively, in the diet. In conclusion, microhistological analysis is a useful tool for determining botanical composition of horse diets when grazing cool season grass pastures.

No description available.

Re-introducing heterogeneity to native North American rangelands is imperative to maintaining grassland biodiversity, and it has been suggested that using a variety of cattle grazing intensities on the landscape could accomplish this. I used generalized linear mixed models to describe the effects of grazing intensity on vegetation structure, plant species diversity and plant communities over four years. I used the Mantel test and non-metric multidimensional scaling to illustrate changes in plant communities with varying grazing intensities and over time. Effects of grazing were cumulative and changed over time, upland and lowland habitats responded differently to grazing intensity, and heterogeneity was maximized at the landscape scale under a variety of grazing intensities. When conservation is the primary goal, a variety of grazing intensities on the landscape can be used to increase heterogeneity, and therefore grassland biodiversity.

Grassland bird species have declined dramatically since 1966. This decline can be linked to changes in land use practices, such as grazing. I examined the effects of cattle grazing on the abundance of birds by testing the predictions of the More Individuals Hypothesis (MIH). The study was conducted in Grasslands National Park of Canada (GNPC) in Saskatchewan. Point counts were used to sample richness and relative abundance of birds. I sampled two groups of invertebrates: grasshoppers and carabid beetles. In addition, vegetation measurements were taken to assess the intensity of grazing. I found that (1) grasshopper abundance, richness and diversity were higher in grazed pastures; (2) carabids showed mixed responses to grazing; (3) bird abundance was correlated with carabid abundance, thus supporting the assumptions of the MIH. Overall, my results indicate that grazing can be beneficial for both birds and their invertebrate prey in southern Saskatchewan mixed-grass prairies.

No description available.

No description available.

Thesis (Ph.D.)--University of Melbourne, School of Agriculture and Food Systems, Institute of Land and Food Resources, 2002. / Typescript (photocopy). Includes bibliographical references (leaves 182-198).

Thesis (Ph. D.)--University of Washington, 2008. / Vita. Includes bibliographical references (p. 300-330).

Thesis (M. Agr. Sc.) -- Lincoln University, 2008. / Also available via the World Wide Web.