Ecology and Evolutionary Biology Commons^™

Effects Of Polyacrylamide On Rangeland Soils And Plants, Saud Leily R. Al-Rowaily

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objectives of this study were to determine the effects of two forms of polyacrylamide (PAM) conditioners (Cross-linked and Non-cross-linked PAM) on evaporation, saturated hydraulic conductivity, water retention, crust and crack formation of soils, seed germination, and seedling and tubeling growth.

The two PAM conditioners, 0.2% concentration by weight, were mixed with seven soils of different textures (sandy loam, silt, silty clay loam, silt loam, fine sand, medium sand, and coarse sand) to investigate the effects on evaporation, saturated hydraulic conductivity, and water retention. Soil samples of different textures were brought to field capacity and placed in a growth chamber …

Reproductive Ecology Of Wyoming Big Sagebrush (Artemisia Tridentata Ssp. Wyomingensis) : Effects Of Herbivory And Competition, Richard T. Decker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Herbivory and plant competition affect sexual reproduction of plants in various ways. Exclusion of mule deer (Odocoileus hemionus) and cattle, removal of plant competition (both inter- and intraspecific), and all combinations of the above treatments were used to examine the individual and combined affects on Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) reproduction. Reproduction of Artemisia tridentata ssp. wyomingensis was divided into hierarchical levels of the number of: (1) modules per current-year ' s growth (CYG), (2) nodes per module, (3) inflorescence heads per node, (4) achenes per inflorescence head and (5) percent viable achenes. Counts at hierarchical …

Forest Canopies: Form And Functional Relationships, Steven B. Jack

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest canopy structure is strongly influenced by stand density due to changing competitive interactions among the individual trees and in turn directly influences stemwood volume production. The structure and dynamics of forest canopies, particularly in relation to the production of stemwood, were examined in unmanaged, even-aged stands of two dissimilar tree species, Pinus contorta var. latifolia Engelm. and Abies lasiocarpa (Hook.) Nutt. The analysis of structure-production relationships was guided by a conceptual model which generated hypotheses and led to examination of assumptions incorporated in the model.

Mean crown dimensions were related to stand density through a negative exponential function for …

Comparative Foraging Ecology Of Sheep And Goats In Caatinga Woodland In Northeastern Brazil, Scott L. Kronberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small-ruminant production is an important part of the agricultural economy of northeastern Brazil. However, mild-to-severe undernutrition of livestock is an annual occurrence. Goats can tolerate the marginal forage conditions better than sheep, but the mechanisms underlying their superior tolerance are not understood.

An analysis of animal liveweights at the end of the year-long study indicated that reproducing mixed-race goats gained nearly twice (P<.05) the weight of reproducing hair-sheep of the Santa Ynez breed, and non-reproducing goats gained about 1.2 times more (P<.05) weight than non-reproducing sheep. Daily weight gains of lambs were less (P<.10) than those of kids for their first 80 days of life.

In the wet season, reproducing sheep and goats gained similar (P>.05) weight, while non-reproducing sheep gained more (P≤.05) than non-reproducing goats. Non-reproducing goats had greater (P<.05) forage organic matter intake (OMI) than the corresponding sheep in the two wet periods. In the late-wet period, non-reproducing goats had greater (P<.05) digestible energy intake (DEI) than corresponding sheep did but had similar (P>.05) digestible protein intake (DPI) as sheep.

In the dry …

The Effect Of Seasonal Cattle Grazing On California Bighorn Sheep Habitat Use, Melanie J. Steinkamp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of seasonal cattle grazing on a newly reintroduced population of California bighorn sheep (Ovis canadensis californiana) in Big Cottonwood Canyon, Idaho, was studied. The hypothesis that bighorn sheep avoid cattle was tested. The issue of avoidance between bighorn sheep and livestock is arguable. Some studies have found that bighorn sheep avoid cattle while others have found no response of bighorn sheep to cattle.

Evidence was found to document the avoidance of cattle by bighorn sheep. The size of the bighorn's home range and core area decreased with the movement of cattle into areas of high bighorn …

The Effects Of Disease, Prey Fluctuation, And Clear-Cutting On American Marten In Newfoundland, Canada, Richard J. Fredrickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Individual variation in survival and behavior of American marten (Martes americana) was studied in relation to disease, prey fluctuation, and clear-cutting from 10 January 1986 through 20 August 1987 in Newfoundland, Canada. Thirty-seven of forty marten captured on the study area were telemetered and monitored for part or all of the study.

Marten mortality was concentrated in two intervals, fall 1986 and late winter 1987. Mortality during fall 1986 was attributable to encephalitis, while marten deaths during late winter 1987 resulted from predation and starvation attributable to the prey decline. Nonsuppurative encephalitis was first detected 7 October 1986; …

A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions.

Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and …

Yellowstone's Northern Elk Herd: Critical Evaluation Of The "Natural Regulation" Paradigm., Charles Edward Kay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Prior to 1968, the National Park Service contended that an unnaturally large population of elk had severely damaged Yellowstone Park's northern winter range, including aspen and willow communities. However, under "natural regulation" management adopted in the earl y 1970s the agency now believes that vegetation changes in the park are due to normal plant succession, climatic change, or fire suppression, not ungulates. The agency also believes that large numbers of elk (12, 000 - 15, 000) have wintered on the park's northern range for the last several thousand years. This study tested several of the major assumptions or predictions of …

Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …

Modeling Forest Dynamics Based On Stand Level Resource Allocation, Geoffrey Candler Poole

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An ecologically based model of forest succession is presented. In the model, trees compete for a share of limited growth resources available from their environment. Competition is reflected by each tree's effect on the resource pool and is not explicitly modeled. Model parameters were fit to field data from subalpine forests of the Rocky Mountains. A technique for estimating model parameters from understory-tolerance rankings and silvical characteristics of each species is also presented. The model's output was consistent with our current understanding of forest dynamics. Emergent properties of the model also mimicked natural processes such as self-thinning, release, and maximum …

Fee Hunting Opportunities On Private Land In Utah: An Economic And Policy Analysis, Lucy A. Jordan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Objectives of this research were (1) to describe fee hunting as it is currently practiced in Utah and (2) to assess the adequacy of fee hunting efforts in addressing the problems of wildlife habitat and hunter access on private land. To collect information, Utah landowners who charged for deer (Odocoileus hemionus) or elk (Cervus elaphus) hunting in 1986 were surveyed by telephone and mail.

Compared to the average Utah livestock rancher, those involved in fee hunting have larger livestock operations and have owned their property longer. They are Utah natives. Fee hunting is concentrated in northern …

Using Computer Imaging To Assess Visual Impacts Of Forest Insect And Disease Pests, Daniel Rabin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Forest insect and disease pests alter the appearance of trees, thereby impacting visual resources. Because of the complexity of most forest landscapes, the degree of visual impact of pest-infested forest stands is difficult to quantify.

This paper describes a method of measuring visual impacts of pest-infested forest stands. Photographs of healthy Ponderosa pine trees were entered into a computer video-image-processing system. Using this system, images of trees were altered to simulate different degrees of infestation by limb rust, a forest pathogen.

The altered and unaltered images were shown to groups of observers who rated the scenes in terms of "scenic …

Management, Foraging Behavior, Diet Composition And Forage Quality Of Free-Ranging But Herded Camels In Ceeldheer District, Central Somalia, Ahmed A. Elmi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In Somalia, camel (Camelus dromedarius) survivability and milk production has been higher than for other domestic livestock and contributes substantially to the subsistence of Somali pastoralists. The objective of this research was to study management, foraging behavior and nutrition of camels in their natural habitat to determine how production continues under seasonal nutritional stress.

Management systems of Ceeldheer pastoralists are based on available natural pasture and water. The natural rotation grazing system maintained an ecological equilibrium in the District.

Pastoralists manipulate their herds to suit existing environmental conditions, family needs and labor availability for herding. In herd management, …

The Feasibility Of River Otter Reintroduction In Northern Utah, Joel P. Bich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this thesis is to document river otter (Lutra canadensis) distribution and reintroduction potential in northern Utah. Distribution was studied using data from 3 sources: 1) otter sighting records from Utah Division of Wildlife Resources; 2) surveys of Utah furbearer trappers and natural resources personnel; and 3) searches of streams for otter sign. Potential for river otter habitat/reintroduction was evaluated by assessing food, cover, and reintroduction attributes. Streams were ranked using an evaluation system based on data from the otter literature.

Forty-six positive otter sightings were made in Utah by trappers, natural resources personnel, and the …

Control And Evaluation Of Big Game Browsing Damage To Commercial Fruit Orchards, William E. Stone

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Diversionary feeding, artificial feeding designed to divert animals away from areas where they might cause property damage, was tested for efficacy in reducing fruit orchard browsing by big game animals during two consecutive winters in Utah. Strategically placed attractive feedstuffs lured deer to feed stations and reduced fruit-bud browsing (1st year, P < 0.07; 2nd year, P < 0.01). Blossom and apple numbers were greater (P < 0.05) on trees in the feed (treatment) orchard than in the no feed (control) orchard in each year. However, higher (P < 0.05) apple production on trees where browsing was excluded in the treatment orchards compared to the control orchards indicated that intercept feeding did not increase crop production. Tree periodicity and other factors affecting apple production masked the effect of diversionary feeding on crop yield.

Two independent browsing damage assessment methods, a paired-tree technique and a harvest-inflation technique, predicted that the ratio of apples lost per browsed bud was 0.158 and 0.082, respectively. However, the values of the ratio varied widely with each method of estimation. Browsing damage differed ( …

The Effects Of Forest Harvesting On Small Mammals In Western Newfoundland And Its Significance To Marten, Brian Tucker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The depauperate fauna of Newfoundland provides a limited prey base for marten. Only two small mammal prey species, Microtus pennsylvanicus and Sorex cinereus, were found in any abundance in the old-growth forests of the study area. Of these two, Microtus displayed population fluctuations typical of most microtines. Analysis of marten scats indicated that Microtus is a very important prey item to the marten with other food. items being of lesser importance particularly when Microtus are abundant.

Trapping in various habitats indicated that Sorex densities were three to five times higher in logged areas compared to uncut areas. Unfortunately, the …

A New Approach To Forest Site Quality Modeling, David L. Verbyla

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Multiple regression and discriminant analysis procedures are commonly used to develop forest site quality models. 'When they contain many independent variables relative to sample size, these models may be subject to predicton bias. Fit statistics such as R² in regression and classification tables in discriminant analysis show the apparent model accuracy but this may be a biased estimate of the model's actual accuracy. Sample splitting methods such as cross-validation and the bootstrap can be used to get an unbiased actual accuracy estimate.

A discriminant procedure called classification tree analysis uses cross-validation to build the classifier with the greatest estimated …

Nutrient And Water Interrelationships Between Crested Wheatgrass And Two Shrub Species, Paul B. Baker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

When crested wheatgrass (Agropyron desertorum) grows in mixture with sagebrush (Artemisia tridentata), its production declines. Its production increases when grown in mixture with fourwing saltbush (Atriplex canescens), according to previous reports. This study investigated soil water extraction and potassium (K) nutrition of the two shrubs to identify possible causes of the differential responses of crested wheatgrass.

Crested wheatgrass had reduced, rather than increased, nitrogen (N) and K yield in mixture with fourwing saltbush. No differences in N and phosphorous (P) concentrations were observed between sagebrush and fourwing saltbush, but fourwing saltbush had a much …

Acquisition Of Forgaging Skills By Lambs Eating Grass Or Shrub, Enrique R. Flores

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I studied the acquisition of foraging skills by lambs eating shrub or grass in three experiments. The general approach was to isolate those skills involved in prehending forage from those related to the acceptance of novel foods. Treatment lambs received 15 times more exposure to grass or shrub than did control lambs. Lambs were tested in 2.5 x 2.5 meter monocultures of shrub or grass 5 min/d, on two separate occasions. Height, bulk density and spatial arrangement of plant material were controlled during testing.

In Experiment 1, I studied the acquisition of foraging skills by lambs on monocultures of shrubs. …

Nesting And Habitat Parameters For Selected Raptors In The Desert Of Northwestern Utah, David L. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the effects of habitat parameters, disturbances and predation on the reproductive success of golden eagles (Aguila chrysaetos), ferruginous hawks (Buteo regalis), red-tailed hawks (Buteo jamaicensis) and prairie falcons (Falco mexicanus) in the desert area southwest of the Great Salt Lake in northwestern Utah.

The prairie falcon was the only species examined that had a normal reproductive output during the study years of 1984-1986. The prairie falcon was better able to utilize the avian prey species which were very difficult for the larger and slower raptor species to capture. During …

Effect Of Fertilization On Woody Plant Chemistry: The Role In Diet Selection By Goats, Amanuel Gobena

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Lack of forage quantity and quality limit livestock production during the dry season in northeast Brazil. Coppice produced following cutting of tree species in this area has the potential to increase forage quantity and quality during the dry season, because trees that coppice retain green foliage throughout most of the dry season. However, the palatability of coppice is often low.

From a theoretical standpoint, woody plants with inherently slow growth rate should be less palatable to herbivores than plants with inherently fast growth rates, because plants that grow slowly allocate more carbon to compounds such as tannins and resins that …

Inter-Seasonal Range Relationships Of Spanish Goats And Mule Deer In A Utah Oakbrush Community, Robert Alexander Riggs

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three experiments were conducted to assess the potential for using Spanish goats to manage Gambel oakbrush winter range, dominated by Gambel oak (Quercus gambelii), for mule deer (Odocoileus hemionus). Summer-time food selection of goats, effects on plant community composition, and consequent effects on mule deer nutrition and foraging behavior were examined.

An apparent preference for juvenile oak browse, and low use of oak twigs was observed. Selection for juvenile browse may have been facilitated by the retarded phenology of oak as compared to that of associated flora. This differential was maintained by repeated browsing. Animal performance, …

Disturbed Alpine Ecosystems: Seedling Establishment Of Early And Late Seral Dominant Species, Jeanne C. Chambers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the effects of seedbed and seedling environment on establishment of early and late seral dominant alpine species. Species studied included late seral dominant forbs (Geum rossii, Artemisia scopulorum, and Polemonium viscosum), early seral dominant forbs (Potentilla diversifolia and Sibbaldia procumbens), a late seral dominant grass (Festuca idahoensis), and early seral dominant grasses (Calamagrostis purpurascens and Deschampsia cespitosa). Germination responses of each species to wet vs. dry cold stratification and light vs. dark conditions were investigated. No statistical differences were observed in the seed germination of early and late …

Autecological And Grazing Control Studies Of Dyers Woad (Isatis Tinctoria L.) On Northern Utah Rangelands, Kassim O. Farah

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dyers woad (Isatis tinctoria L.) is a noxious weed on northern Utah rangelands. Chemical and mechanical means of control are unsuitable for rangelands. A potential alternative, biological control, is difficult due to a lack of basic ecological information. To remedy this, some aspects of the population biology and autecolgy of dyers woad were studied. The feasibility of controlling dyers woad by early spring grazing was also investigated via clipping experiments.

A population study followed the survivorship of experimentally established populations over two years. Fall germinating individuals (1984) overwintered as rosettes twice and all survivors reproduced successfully. Spring germinating individuals …

Factors Affecting The Sprouting Response Of Woody Caatinga Species And Their Implications For Improved Caatinga Management, Linda Howell Hardesty

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In northeast Brazil grazing is a major use of much of the semiarid woodlands (caatinga). Animal production is limited by lack of dry season forage, primarily deciduous tree leaves. Management is constrained by the persistence of undesirable trees that sprout from the stump (coppice). This study evaluates the possibility of manipulating coppicing trees to improve caatinga management, particularly dry season forage production.

The season of cutting can influence coppicing. Trees were cut early and late in the wet and dry seasons. After two years, trees of all species cut in the late wet season produced less biomass than those cut …

Causes Of Seeding Failure Within The Tooele Fire Rehabilitation Project In Northwestern Utah, Jeffrey S. Murphy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The original purpose of this study was to examine the influences of ecological site, seeding method and planting season on rangeland seeding success within the Tooele Fire Rehabilitation Project (TFRP) in northwestern Utah. The major objective of the TFRP, designed by the USDI Bureau of Land Management, was to establish a permanent cover of 'Nordan' crested wheatgrass (Aqropyron desertorum (Fischer ex Link) Schultes), 'Luna' pubescent wheat grass (Thinopyrum intermedium ssp. barbulatum (Schur) Barkw. and D. R. Dewey) and 'Alkar' tall wheatqrass (Thinopyrum ponticum (Podp.) Barkw. and D. R. Dewey) on approximately 20,000 ha of rangeland burned by a wildfire in …

Utilization Of Crested Wheatgrass Plants By Cattle Under Several Grazing Regimes, Patricia Selann Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Patterns of grazing on individual crested wheatgrass plants were studied using scale maps of plant basal outlines within randomly located plots. The occurrence and extent (part of plant grazed, stubble height) of grazing on each plant was recorded on the maps at two and three day intervals throughout a grazing treatment. Allometric equations for estimating phytomass from plant photosynthetic volume were generated using nonlinear regression analysis. Equations were specific to year. The percent weight remaining in the stubble of a grazed plant was estimated using a second-order polynomial equation relating cumulative percent plant height to cumulative percent plant weight. A …

Intercept Feeding As A Means Of Reducing Deer-Vehicle Collisions, Peggy Wood

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Intercept feeding was tested for its efficacy in reducing deer-vehicle collision frequency by diverting deer movement patterns away from highways using alfalfa hay as an attractant. Ratios of roadkills in control vs. treatment zones of three highway segments indicated that feeding reduced collision frequency. Spotlighting counts of live deer were significantly higher (P < 0.001) in the control than in the treatment zone, supporting the effectiveness of feeding in keeping deer distant from the highway. In a benefit:cost analysis, the benefits accrued by reducing collision frequency exceeded the costs of feeding on each highway both years, with one exception: in 1986 one of the highways demonstrated that particular features of an area may not be conducive to effectively attracting deer away from a highway. I recommend intercept feeding be used with alternate techniques, so that the most appropriate technique is applied in each situation to reduce collision risk.

Belowground Resource Exploitation In Semiarid Plants: A Comparative Study Using Two Tussock Grasses That Differ In Competitive Ability, David M. Eissenstat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The relative competitive abilities of Agropyron desertorum and Agropyron spicatum were compared using Artemisia tridentata transplants as indicator plants. Although these two tussock grasses have similar shoot growth forms and shoot physiological characteristics, they have substantial differences in their competitive abilities. Artemisia had lower survival, growth, reproduction, and water potential when transplanted into neighborhoods of A. desertorum than in neighborhoods of A. spicatum.

Plant attributes associated with the differences in competitive ability were explored. Agropyron desertorum and A. spicatum have remarkably similar potential growth rates at warm soil temperatures. In a prolonged cold soil temperature treatment in the greenhouse, …

Estimating Optimum Overstory Vegetation Reduction For Increasing Understory Production, John A. Tanaka

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to investigate analytical approaches for estimating the optimum (profit maximizing) rate of initial overstory kill for increasing seasonal forage availability on a specific ranch. The models were developed using the big sagebrush (Artemisia tridentata) - crested wheatgrass (Agropyron cristatum, A. desertorum) vegetation type on a Utah cow-calf-yearling operation as an example. The models should be applicable on any ranching situation where understory forage production is constrained by the establishment and growth of undesirable overstory vegetation.

Three model forms were developed and compared for their applicability to on-the-ground investment decision …