Beef production in the arid Southwest depends on range forages. Forage quality and quantity primarily results from amount, intensity and timing of precipitation. Twenty-three years (1978-2000) of precipitation and animal production data were evaluated. Two major questions addressed were: Does rainfall timing affect number and weight of calves weaned? Does grazing system reduce immediate drought impact on calf production? Three grazing systems were evaluated: Year-round grazing, Savory rotational grazing and Santa Rita rotational grazing (50-60hd, 80-150hd and 50-65hd/year respectively). Winter (P < 0.05), summer (P < 0.01) and previous fall (P < 0.01) precipitation affected calf crop. Only summer precipitation (P < 0.01) had a significant effect on weaning weight. Calf crop did vary between grazing systems (P < 0.01). Savory system had the heaviest weaning weight, total production, and lowest maintenance cost; followed by Santa Rita and year-round respectively (P < 0.01). Maintenance cost per kg calf weaned was similar between rotational systems, but higher in year-round (P < 0.01).

I investigated the effects of winter prescribed burning on relative abundance and species richness of birds in mesquite (Prosopis glandulosa)-grassland at the Welder Wildlife Foundation Refuge, Texas, from June 1995 to August 1996. Relative abundance (P=0.246) and species richness (P=0.622) of breeding birds were not different, but mourning doves (Zendaida macroura) (P=0.058) and great-tailed grackles (Quiscalus mexicanus) (P=0.084) increased, and black-bellied whistling ducks (Dendrocygna autumnalis) (P=0.040) declined in burned treatments. Relative abundance of wintering birds was greater (P=0.002) in burned treatments, but species richness was not different (P=0.602). Mourning doves (P < 0.001) and savannah sparrows (Passerculus sandwichensis) (P=0.001) increased, but grasshopper sparrows (Ammondramus savannarum) (P=0.009), Le Conte's sparrows (Ammondramus leconteii) (P=0.001), and sedge wrens (Cistothorus platensis) (P=0.001) declined in burned treatments in winter.

I studied 1,472 locations of desert mule deer (Odocoileus hemionus crooki) (1M, 6F) before completion of the Hayden-Rhodes Aqueduct (HRA) (pre-HRA, 1981-1984), and 2,300 locations (6M, 10F) after completion of the Hayden-Rhodes Aqueduct (post-HRA, 1989-1991) to examine habitat use. I used a Geographic Information System to measure and analyze deer locations by season, sex, and year. I compared home-range size, distance to water catchments, distance to washes, vegetation use versus availability and deer interactions ≤1 km from the canal between the periods. Home-range sizes did not change significantly (P≤0.05) as a result of completion and operation of the HRA. Deer were closer to water catchments in the warmer seasons before completion of the HRA, but farther from water in the warmer seasons after completion of the HRA. Deer locations ≤1 km from the HRA increased after completion and operation of the HRA. Deer were probably relying on areas ≤1 km from the canal for forage and thermal cover.

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Thesis (M.App.Sc.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 2001. / Bibliography: leaves 308-333.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "May, 2008." CD-ROM contains Adobe Acrobat copy of thesis, power-point presentation entitled: Effectiveness and reliability of photo-pair interpretation, and photographs taken during the study. Includes bibliographical references. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2009]. 1 microfilm reel ; 35 mm. Online version available on the World Wide Web.

Thesis (M.Phil.) - University of Queensland, 2005. / Includes bibliography.

Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Nov. 16, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Ecology, Department of Biological Sciences, University of Alberta." Includes bibliographical references.

CAPES / Os objetivos deste trabalho foram avaliar a influencia de períodos de pastejo em trigo duplo propósito sobre a taxa de decomposição das plantas e liberação de nutrientes (N, P, K, Ca e Mg) bem como a produtividade de soja cultivada na sequencia em sistema de semeadura direta. Os tratamentos foram arranjados em delineamento blocos ao acaso com duas repetições. Os tratamentos foram os seis períodos de pastejo (0, 21, 42, 63, 84 e 105 dias) e a taxa de decomposição do material residual destes, foi avaliada pela técnica de litter-bag. A percentagem de biomassa e nutrientes no compartimento mais prontamente decomponível aumentou à medida que aumentou os períodos de pastejo, principalmente devido ao efeito do animal sobre a renovação dos tecidos foliares, o que resultou em uma maior taxa de decomposição da palhada e de liberação de nutrientes para o solo e, consequentemente para a cultura da soja cultivada na sequencia em sistema de integração lavoura pecuária. Entretanto a produtividade de grãos de soja reduziu com o aumento dos períodos de pastejo principalmente devido à diminuição de resíduo de matéria seca sobre o solo. / The aims of this work were to evaluate the influence of dual purpose wheat grazing periods on plant decomposition rates and nutrient release (N, P, K, Ca e Mg) and soybean yielded cultivate in sequence in no-till systems. Treatments were laid out as a random block design with two replications. The treatments were six grazing periods (0, 21, 42, 63, 84 e 105 days), on continuous stocking rate grazing method. From these treatments, dual purpose wheat biomass and nutrients decay constants were evaluated along 7 different field incubation periods (0, 15, 35, 63, 98, 139 e 196 days after soil deposition) by the litter bag technique. The percentage of biomass and nutrients at the easily decomposable compartment increases with the increase of grazing periods, due to the influence of the animal over the plants tissue turnover, which results in highest decomposition rate and nutrients release to the soil and consequently to the soybean cultivated in sequence on crop-livestock system. However the soybean grains yielded reduced with the increase grazing periods mainly due to the diminished of dry matter residue over the soil.