Ecology and Evolutionary Biology Commons^™

Sheep Behavior And Vulnerability To Coyote Predation, Ernest Albert Gluesing

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the activity patterns and social relation ships between individuals in a large herd of domestic sheep (Ovis aries) in an effort to determine if behavioral characteristics predisposed certain individuals to coyote (Canis latrans) predation.

The research was conducted on the Cook Ranch near Florence, Montana, from March through September of 1975. Data were collected from a herd of 627 ewes and 1082 lambs, each individually identifiable. A random sample of 44 ewes and their 75 lambs were intensively studied over a 16-wk period to establish activity budgets and the relationships between sheep activity …

Relationships Of Vegetation To Environment In Canyonlands National Park, Walter Lee Loope

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The vegetation of Canyonlands National Park, Utah, has been described from 157 samples located throughout the Park. Species frequency, density and cover were recorded along with measurements of soil thickness, slope, aspect, elevation and geologic substrate at each site. Measurements of soil texture, pH, and electrical conductivity were taken for a representative subsample. A map of the vegetation of the Park was made by relating the sample points to their corresponding spectral signatures on vertical aerial photographs and locating boundaries between vegetation units by means of changes in photo signatures.

Vegetation in these arid to semi-arid environments appears to be …

Aspects Of The Life History Of Three Catostomids Native To The Upper Colorado River Basin, Charles W. Mcada

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution, abundance and life history were studied for three catostomids -- the razorback sucker (Xyrauchen texanus), the flannel-mouth sucker (Catostomus latipinnis), and the bluehead sucker (Catostomus discobolus) -- all native to the upper Colorado River basin. The razorback sucker has declined in abundance due to man's impact upon the system and it has been recommended that this species be listed as ''threatened" on the U. S. Department of the Interior's list of Threatened or Endangered species [Personal corrmunication, G. C. Kobetich, U. S. Fish and Wildlife Service, Las Vegas, Nevada]. During this investigation, …

Rodent Density And Species Composition In The Snake River Birds Of Prey Natural Area, Idaho, Jon R. Montan Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rodent densities were estimated in the major vegetation types of the Snake River Birds of Prey Natural Area in 1975 and 1976 by a combination of live-trapping and kill-trapping. Only deer mice (Peromyscus maniculatus) were numerous enough to permit reliable density estimates. Relative densities of other rodent species were indicated by kill-trap capture rates. Densities of deer mice correlated well (r = 0.99) with kill-trap capture rates. The use of kill-trapping in place of live-trapping in 1976 permitted extensive sampling throughout the 1930 km² study area. Differences were found among the major vegetation and land-use types in …

Competitive Interaction In Plant Populations Exposed To Enhanced Uv-B Radiation, Fred M. Fox

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Competitive balance and changes in individual plant growth parameters of eight pairs of plant species exposed to enhanced UV-B irradiation were determined under field conditions simulating ozone reductions of about 0.08 atm·cm. The levels of irradiance represented ozone decreases of about 25-30 percent from approximate ambient ozone concentrations for high solar altitudes on clear days during the study. A method for calculating and statistically analyzing relative crowding coefficients was developed and used to evaluate the competitive status of the species pairs sown in a modified replacement series. The effect of UV-B irradiance was generally detrimental to plant growth, and was …

The Effect Of Four Mine Spoil Treatments On The Seedling Water Relations Of Two Plant Species, Lorraine K. Van Kekerix

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Surface mines in mountainous areas cause environmental deterioration at lower elevations in the watershed. The most successful long term solution to the downstream problem is revegetation. However, mine spoils are low in essential plant nutrients, have low water holding capacity, and are often acidic. These factors limit plant colonization. Plants must also be adapted to the environmental conditions of high elevations.

At the McLaren Mine, }1ontana, at 2800 m, it was observed that seedlings on revegetation plots were desiccated, indicating possible water deficits. Field and growth chamber studies were carried out to determine the effects of some spoil ameliorating treatments …

Biological Manipulation Of Blackbrush (Coleogyne Ramosissima Torr.) By Browsing With Goats, Frederick D. Provenza

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to provide data on responses of Angora goats and blackbrush (Coleogyne ramosissima) to a biological manipulation program. Blackbrush utilization levels averaged 30, 16, and 6 percent (545, 367, and 147 kg per hectare) for the heavily, moderately, and lightly browsed pastures, respectively; removal rates of 77, 38, and 19 percent (1164, 582, and 291 kg per hectare) were projected.

Statistically significant differences in body weight loss (P=0.052) were noted for goats browsing in different replications. Goats lost an average of 14 and 19 percent of body weight in replications one and two, …

Leaf Epidermal Transmittance Of Ultraviolet Radiation And Its Implication For Plant Sensitivity To Ultraviolet-Radiation Injury, Ronald Robberecht

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Leaf epidermal transmittance of ultraviolet radiation (280-400 nm) was examined in several plant species to determine the capability of the epidermis to attenuate solar ultraviolet radiation. Epidermal samples were mechanically isolated and examined with a spectroradiometer/integrating sphere for transmittance. A survey of 25 species exposed to natural insolation was conducted. Although the species differed in life form, habitat type, and epidermal characteristics, epidermal transmittance was generally less than 10%. Ultraviolet radiation was attenuated 95 to 99% in more than half of the species. In 16 species, flavonoid and related pigments in the epidermis accounted for 20 to 57% of the …

Feeding Behavior Of Pen Reared Mule Deer Under Winter Range Conditions, Michael A. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the feeding responses of mule deer to a system of spring livestock grazing. The specific purposes were 1) to determine botanical composition of diets selected by mule deer on a winter range subjected to previous spring grazing by sheep compared to one with no sheep grazing and 2) to develop a basis for predicting selection of individual plants by deer, based on physical characteristics of the plants and the species and physical proximity of associated plants.

The study was conducted within the framework of a completely randomized experimental design with two treatments. Variables controlled for each unit …

Forage Selection And Nutrition Of Sheep And Goats Grazing In The Tunisian Pre-Sahara, Rudolfo Ricardo Griego

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nomadic pastoralism has been the traditional method of utilizing grazing resources in arid and semi-arid regions of Africa. However, increased sedentarization accompanied by growing human and animal populations during the past two decades is thought to be accelerating the desertification process, or desert expansion. The specific interactions of the grazing animal with this process has been speculated upon but not studied in detail. A comparative study was initiated during the spring grazing season of 1974 to determine sheep and goat nutritional and production responses, as well as patterns of vegetative selection and utilization under the pastoral system currently employed in …

Nutritional Quality And Herbage Production Of Intermediate Wheatgrass (Agropyron Intermedium [Host] Beauv.) When Infested With Black Grass Bugs (Labops Hesperius Uhler), Alan M. Gray

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two intermediate wheatgrass seedings with different levels of grass bug infestation were evaluated for herbage production, seedhead production, percent dry matter, crude protein, and cell contents. Study sites were located at different elevations on mountain summer ranges in northern (Site I) and central (Site II) Utah. Study plots at Site I and Site II were infested with 113 and 210 bugs per sweep, respectively. Herbage production appeared to be reduced in early spring on the site with the higher infestation; however, no effect on season-long herbage production could be detected on either site. Seedhead production on infested plots was reduced …

Plant Light Responses Under Snow, Steven G. Richardson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Several montane plant species and one alpine species were observed to grow under snow, and the seeds of 19 species germinated under snow. The spectral irradiance of light penetrating up to 198 cm of snow was measured with a device employing a photomultiplier tube and a series of interference filters. In deep snow, the measured peak in transmission was near 500 nm, but in older, more shallow snow the peak was at 550 nm. On two occasions measurements were made both before and after sunrise. There was a shift in the spectra toward the longer wavelengths as the sun rose …

Factors Influencing Germination And Seedling Survival Of Several Varieties Of Astragalus Lentiginosus Dougl., Paul Ziemkiewicz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Astragalus lentiginosus, which consists of 36 varieties, is one of the principal locoweeds of western North America. The objectives of this study included identification of some of the major factors affecting germination of the seed and survival of the newly established seedlings for several of these varieties.

The seeds of the varieties studied exhibited two mechanisms for dormancy. One is a seed coat that is impermeable to water, and the other is a water-leachable inhibitor. The presence or absence of low-intensity incandescent light (in 14-hour day lengths) had no effect on germination. Of three temperature regimes studied, the regime …

Exploratory Sensitivity Analysis Of A Stream Ecosystem Model, Joseph H. Wlosinski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The framework of a stream ecosystem simulation model is described. Using this framework and data from two different geographical areas, a cold desert stream and a generalized mountain stream, exploratory sensitivity analysis was performed on the model. This was accomplished by qualitatively comparing outputs of a series of simulations in which a different level of a driving variable was used in each simulation. Based on these results, recommendations are made for improving the structure of the model.

A Study Of The Radiation Quality Under Plant Canopies In The Wave Range 0.4 To 2.5 Microns, Nolasco G. Baldazo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The spectral distribution of the global radiation from 0.4 to 2.5 microns penetrating deciduous and coniferous canopies were measured during clear days between 10 a.m. and 2 p.m. using a double-quartz monochromator.

In the visible region (0.4 to 0.7 micron) the average relative spectral transmissions under both canopies are about one percent beginning at 0.4 micron and decreasing to about half a percent at 0.67 micron. There is only a small peak in the green (0.55 micron) transmission under deciduous stands while there is none under coniferous canopies. The slightly higher transmission in the blue (0.4 micron) is attributed to …

The Dynamics Of Root Growth And The Partitioning Of Photosynthates In Cool Desert Shrubs, Osvaldo Alberto Fernandez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study addresses the nature of physiological and phenological evolutionary strategies of root growth dynamics and energy allocation followed by Atriplex confertifolia, Ceratoides lanata, and Artemisia tridentata growing in their natural cool desert environment.

Root observation chambers with inclined Plexiglass windows were installed in monospecific desert communities of Atriplex confertifolia, Ceratoides lanata and Artemisia tridentata. Soil temperature and water potential measurements taken immediately adjacent to the observation windows indicated a minimal disturbance was caused by the presence of these chambers. For the three species initiation of root growth was observed before initiation of shoot activity, furthermore, active root growth extended …

Effects Of Exercise On Serum Lactate Dehydrogenase Activity Of Catchable-Size Hatchery Rainbow Trout, Salmo Gairdneri, Gerlad T. Klar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effects of exercise and the relative condition of exercised fish were viii evaluated for two strains of rainbow trout. Circular tanks fitted with a paddle were used to continuously exercise the fish and a stamina tunnel was used to evaluate the condition of exercised trout. Trout were exercised continuously at one fish-length per second and one-half fish length per second. Serum LDH activity in Shephard-of-the-Hills (Missouri) rainbow trout acclimated to 10 C increased two fold during the first four days of exercise. Serum LDH activity returned to control levels by the tenth day of exercise. Serum LDH activity in Shephard-of-the-Hills …

Bromegrass Productivity In Relation To Precipitation, Shrub Canopy Cover And Soil Nitrogen Content, Lawrence G. Kline

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In seasons of above normal precipitation, populations of annual weedy species increase in great abundance in semi-arid desert plant communities. These increases in biomass tie up a considerable portion of the available nitrogen of such ecosystems and may depress subsequent annual grass germination.

A big sagebrush-annual bromegrass plant community was irrigated to simulate a spring growth period of abundant precipitation amenable to annual bromegras s productivity. Productivity and nitrogen content parameters were monitored throughout the spring and summer to evaluate the short and potential long term effects of this seasonal increase in "precipitation".

Irrigation increased annual bromegrass productivity almost 50 …

Internal Water Potential Of An Engelmann Spruce Stand In Relation To Soil And Atmospheric Factors, Richard L. Meyn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The primary objective of this study was to determine the degree of correlation between internal water potential of Engelmann spruce trees and selected environmental factors. The secondary objective of the study was to determine the effect of summer precipitation, both in meadow and forested sites, on the soil drying cycle.

Four study plots (each roughly 154 square meters) under spruce cover and two study plots (100 square meters) in a small meadow were established. At each spruce plot, a thermocouple psychrometer was installed at one meter above the ground on the north side of three selected, mature Engelmann spruce trees. …

Mechanisms Of Population Regulation In Confined Colonies Of Peromyscus Maniculatus (Wagner) And The Response To Exploitation, Donna Corn Olsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wild-trapped and laboratory-reared Peromyscus maniculatus (Wagner) were raised as confined colonies indoors with various stocking densities ranging from 0.026 to 0.100 mice per sq. ft. in pens of 40, 77, and 154 sq. ft. The animals were individually tagged and all pens were censused at weekly or semi-monthly intervals to record animals present, body weights, food consumption, and overt reproductive condition. At the termination of each experiment, all mice were necropsied and organ weights of gonads and adrenals recorded. Histological sections were made of the testes and ovaries. Half the colonies were subjected to density-independent exploitation by removal of 50% …

Annual Periodicity In A Free-Living Hibernator, The Uinta Ground Squirrel, Fred L. Knopf

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study documents the timing of seasonal events and associated changes in body weights of Uinta ground squirrels (Spermophilus armatus) that live at three different altitudes. The investigation provides detailed field data for biologists investigating circannual rhythms and hibernation in the laboratory.

Ground squirrels aroused and subsequently emerged from hibernation in an overlapping sequence: adult males first, followed by adult females, yearling females and yearling males. Within limits some climatic condition(s) delayed emergence and increased the overlap in emergence sequence. The duration of seasonal activities above ground averaged about 90 days for adult and yearling squirrels. Juveniles were …

Field Measurements Of Photosynthesis And Leaf Growth Rates Of Three Alpine Plant Species, Douglas A. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Leaf photosynthetic measurements using a portable ¹⁴Co₂ field system were carried out and correlative leaf relative growth rates, RGR, were determined at different leaf positions of three alpine plant species throughout the growing season. Initially there was a period of high leaf RGR associated with a period of increasing photosynthetic activity. Following this stage was a long period of no net change in length of the living leaf. During this period, photosynthetic activity generally increased to a maximum level and then decreased steadily. The final ontogenetic stage was a period of negative leaf RGR denoting leaf senescence which …

Trout Movements In A Small Mountain Stream, Thomas Mark Twedt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Five groups of 400 hatchery rainbow trout, (Salmo gairdneri), were stocked in a small, mountain stream at 3-week intervals from June to September, 1972. A fish trap captured any fish moving out of a 500 m study section.

Fish began moving at high levels during the first day of each stocking and continued at high rates for 5-8 days (Early Phase), after which movement decreased to low levels for 6-9 days (Late Phase). Early Phase fish moved primarily at night, possibly due to their disoriented state and high subjectivity to stream conditions. Fish moving during Late Phase did …

Autecological Life History Studies Of Two Geraniums, Geranium Richardsonii And Geranium Nervosum, Becky Lee Green

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two perennial species of wild geranium (Geranium nervosum Rydb. and G. richardsonii Fisch, and Trautv, [Geraniaceae]) which grow throughout the mountainous regions of western North America were studied to determine the factors influencing the life stage development and distribution of these plants. Attempts were also made to provide some information to assist in the taxonomy of this genus.

Geranium richardsonii is found in wet meadows and along streambanks throughout its distribution. Geranium nervosum frequents rocky hillsides and drier meadows throughout its range.

Seeds of G. nervosum had 65%, germination in the stratification pretreatment. Geranium richardsonii seeds required scarification to …

Habitat Selection By Large Wild Ungulates And Some Aspects Of The Energy Flow In A Sub-Tropical African Savanna Woodland Ecosystem, Stanley M. Hirst

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study of habitat selection by large wild ungulates was carried out on a 50 cm² area in the sub-tropical Lowveld region of eastern Transvaal province, South Africa. Estimations were made of herbaceous forage net productivity and ungulate secondary productivity on the same area.

Fourteen vegetation types, varying in composition and structure from open savanna to dense woodland, were delineated by association analysis. Structural and vegetational characteristics which were considered to influence ungulate distribution were measured within each vegetation type.

The study area supported resident populations of seven ungulate species during the wet season; drv season densities were higher …

A Seed Demography Model For Finding Optimal Strategies For Desert Annuals, J. Curtis Wilcott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A theoretical investigation of the factors that affect the population dynamics of annual plants growing in deserts was conducted through the use of computer modeling techniques. A series of three models of the yearly life cycle of desert annuals was constructed and their behavior examined. The dissertation centers around the third and most complex model, a computer simulation model with distinguishable seed cohorts in a randomly varying rainfall environment. A typical simulation run was for 80 years and cost $1.00.

The five plant functions were (l} seed losses (mainly predation) as a function of seed age, (2) seed dormancy as …

Population Ecology Of Uinta Ground Squirrels, Norman A. Slade

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The behavior and ecology of Uinta ground squirrels (Spermophilus armatus) at the Utah State University Forestry Field Station northeast of Logan, Utah were studied from 1964-1971 to determine the role of behavior in population regulation. From 1965 to 1968, data were collected to establish population norms. In 1968, the population density was reduced experimentally to help elucidate regulatory processes. This paper compares the dynamics of the population before and after the population reduction.

Before the density reduction, juvenile survival was lower than that of yearlings and adults. The disappearance of juveniles was associated with their tendency to disperse …

Early Life History Of The Mountain Whitefish Prosopium Williamsoni (Girard) In The Logan River, Utah, Lawrence Guy Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Growth and food habits of 399 Age 0 mountain whitefish from the Logan River, Utah, were studied between March, 1970, and April, 1971. At the end of their first six months of life, whitefish were 86-96 mm total length and weighed 6-8 grams (wet). Total temperature experience was 2,950-3,430 degree-days above 32° F. The length-weight relationship for Age 0 mountain whitefish was best described by three stanzas with slopes of 4.3333 for fish 12.5-17.0 mm total length, 3.4437 for fish 17.0-55.0 mm total length, and 2.8043 for fish 50.0-112.0 mm total length. Scalation commenced at 30-35 mm total length and …

Reproduction And Hematology Of The Cache Elk Herd, Thomas B. Follis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The initial three years of a 10-year reproductive study of elk involved three major phases. A fourth was added because of convenience. Objective 1 was to ascertain pregnancy rates in yearling and mature elk by rectal palpation, associate these rates with subsequent fall cow/calf ratios, and to test concurrently an ultrasonic fetal heart detector. Rectally observed anatomical changes in gravid uteri of cattle were directly applicable to elk. Ultrasonic detections of pregnancies in elk and deer were unsuccessful.

Pregnancy rates in the 1969-70 winter of 100 and 0 percent, respectively, for 19 adult and five yearling elk were associated with …

Some Aspects Of Conditioning Behavior In Rainbow Trout, Salmo Gairdneri, Reed E. Harris

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effects of exercise, social facilitation, and delayed conditioning after vi exercise on the learning behavior of 5 to 6-inch rainbow trout, Salmo gairdneri, was measured in a conditioned avoidance response apparatus. The conditioning schedule contained an intertrial interval between alternate presentations of conditioned (light) and unconditioned (shock) stimuli. This randomization eliminated learning losses found in a previous study. Mean percentage avoidance, the measurement of learning, did not decrease significantly during conditioning trials. Exercised fish learned avoidance better than did non-exercised fish. Mean percentage avoidance for fish exercised at 0.5 ft/sec was 66.3; at 1.0 ft/ sec, 1.5 ft/sec, and …