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Full-Text Articles in Life Sciences

Nest Success Of Dabbling Ducks In A Human-Modified Prairie: Effects Of Predation And Habitat Variables At Different Spatial Scales, Jaime E. Jimenez May 1999

Nest Success Of Dabbling Ducks In A Human-Modified Prairie: Effects Of Predation And Habitat Variables At Different Spatial Scales, Jaime E. Jimenez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nest success of dabbling ducks in the Prairie Pothole region of North America has been declining for the past 40 years in parallel with declines in duck populations. Low nest success seems to result from the combination of an extremely fragmented breeding ground in a human-dominated landscape with an abundant and expanding community of generalist nest predators. Studies that examined variables associated with nest vulnerability to predation have produced contradictory results, likely because of simplistic approaches, lack of spatio-temporal replication, use of artificial nests, and the effect of confounding variables. I attempted to clarify the equivocal findings of previous studies …


Modeling Habitat Attributes Of Cavity-Nesting Birds In The Uinta Mountains, Utah: A Hierarchical Approach, Joshua J. Lawler May 1999

Modeling Habitat Attributes Of Cavity-Nesting Birds In The Uinta Mountains, Utah: A Hierarchical Approach, Joshua J. Lawler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Birds may have the ability to view their environments at a wide range of spatial scales; accordingly, they may make habitat-selection decisions at multiple spatial scales. I investigated the implications of hierarchy theory and a landscape perspective on nest-site selection in cavity-nesting birds in the Uinta Mountains in northeastern Utah. I used three different approaches to address the concept of a multi-scaled nest-site selection process. First, I conducted an exploratory study in which I investigated nest-site selection at three spatial scales for Red-naped Sapsucker (Sphyrapicus nuchalis), Northern Flicker (Colaptes auratus), Tree Swallow (Tachycineta bicolor), and …


Influence Of Type Of Supplemental Carbohydrate On Ruminal Responses And Methane Output From Ruminants Consuming Low-Quality Forage, Raul J. Lira May 1999

Influence Of Type Of Supplemental Carbohydrate On Ruminal Responses And Methane Output From Ruminants Consuming Low-Quality Forage, Raul J. Lira

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In a completely randomized design with a factorial arrangement, three energy supplements and two species (cows and ewes) were evaluated in two identical experimental periods: gestation and lactation. The three supplement treatments were a control, barley, and sugar beet pulp (SBP). The basal diet was tall wheatgrass straw (5.52% CP).

Forage and total dry matter intake (FDMI and TDMI, respectively) interacted (P=.04) with species, supplements, and physiological stages.

An interaction of physiological stage and sampling time occurred for pH. Supplement and sampling time interacted for butyric acid proportion and total VFA concentration.

Diet digestibility displayed an interaction between …


A Social Analysis Of Grazing Management On National Forest Lands: A Case Study In Catron County, New Mexico, Alexis S. Watts May 1999

A Social Analysis Of Grazing Management On National Forest Lands: A Case Study In Catron County, New Mexico, Alexis S. Watts

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The rural west in this country faces increased national pressure concerning the management of natural resources on public lands. Issues regarding natural resource management are becoming more important as they continue to affect rural communities and capture the attention of a variety of interest groups. Natural resource managers are increasingly required to consider social dimensions of resource use and management. Lack of consideration in these areas can lead to dissatisfied, and even hostile, local residents and interest groups. Often land managers face criticism from many groups at once as a result of management decisions.

This study analyzed a particular resource …