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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Effects of Livestock Grazing Management Practices on Greater Sage-Grouse Nest and Female Survival

Dettenmaier, Seth J. 01 August 2018 (has links)
The decline in greater sage-grouse (Centrocercus urophasianus; sage-grouse) populations across western North America has been primarily attributed to loss and fragmentation of their sagebrush (Artemisia spp.) habitats. This habitat loss is largely the result of increased human activities, with grazing by domestic livestock as the most predominant land use across the sagebrush ecosystem in North America. The goal of my research was to increase our understanding of the effects of livestock on sage-grouse populations. I reviewed the peer-reviewed literature for all published studies that reported potential effects of grazing on grouse species worldwide. I found that there was an overall negative effect of domestic livestock grazing on grouse populations in general. I compared sage-grouse nest success on two study sites managed under differing prescribed livestock grazing practices to determine their relative effects on sage-grouse nest survival. I found that nest survival was slightly higher in areas managed under high-intensity low-frequency rest-rotation practices. The difference was not statistically significant (P < 0.05). However, these areas received lower precipitation and were grazed at a higher stocking rate (AUM · ha-1) without negatively affecting nest survival compared to areas of that were mostly grazed as single pastures from May-September. Because livestock grazing in the sagebrush ecosystem has been historically facilitated with sagebrush reduction treatments to increase forage for livestock, I compared the relative effects of these treatments with the more direct effect from livestock grazing. Sagebrush treatments were found to have a greater effect on female sage-grouse survival than livestock grazing. This understanding can be useful for land managers looking to attenuate the effects of management decisions related to livestock grazing systems in the sagebrush ecosystem.
2

Greater Sage-Grouse Seasonal Ecology and Responses to Habitat Manipulations in Northern, Utah

Thacker, Eric T. 01 May 2010 (has links)
Declining greater sage-grouse populations (Centrocercus urophasianus; hereafter sage-grouse) have led to increased concern regarding the long-term stability of the species. Previous research has identified factors contributing to the observed population declines. Habitat degradation and loss have been implicated as major factors in population declines. Although much is known about sage-grouse biology, more information is needed about population responses to specific management actions. This research was conducted to document sage-grouse responses to site-specific management actions. Additionally, I evaluated sage-grouse temporal and seasonal habitat-use and the comparability of techniques used by range and wildlife managers to measure vegetation responses of habitat management. Specifically, I evaluated 1) whether chemical analysis (gas chromatography) of sage-grouse fecal pellets could identify sagebrush species in sage-grouse winter diets, 2) the comparability of the line-point intercept and Daubenmire canopy cover methods for estimating canopy cover, 3) the response of sage-grouse broods to prescribed burns in a high elevation sagebrush community in northeastern Utah, and 4) the vegetation and insect characteristics of sites used by sage-grouse broods during a 24-hour period. I was able to determine wintering sage-grouse diets using gas chromatography by analyzing fecal pellets. This research also confirmed that black sagebrush (Artemisia nova) was an important component of sage-grouse winter diets in western Box Elder County and Parker Mountain populations. The line-point intercept and Daubenmire methods for estimating canopy cover are not comparable. Sage-grouse broods selected small (~ 25 ha) patchy prescribed burns in high elevation mountain big sagebrush (A. tridentata vaseyana) communities in northeastern Utah. Sage-grouse brood-site use in northwestern Utah did not differ during the diurnal hours, but nocturnal roost sites were characterized by shorter statured shrubs and more bare ground when compared to midday sites.

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