Ecology and Evolutionary Biology Commons^™

Information Transfer And Regulation In A Model Ecosystem With Environmental Stochasticity, M. Mckee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The concept of regulation in ecosystems has been given considerable attention in the ecological literature, but no formal treatment has been offered. This study proposes a rigorous definition of regulation which is derived from the mathematics of information and communication theory. A theoretical, mathematical equivalent of the definition is also offered which implies serious limitations as to the value of most traditional laboratory population studies and deterministic population models in understanding regulation in ecosystems. The empirical validity of this theoretical equivalence is tested through use of a competition model of two diatoms. Other observations concerning the relationship between environmental variability …

Some Effects Of A Grazer, Hyalella Azteca On Ecosystem Level Properties In Aquatic Microcosms, Martin D. Werner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study to determine some ecosystem level effects of an aquatic invertebrate grazer, Hyalella azteca, was performed in aquatic ix microcosms. Impact of the grazer was assessed in three general areas: 1) inorganic nutrient levels of the microcosm water column, 2) productivity and respiration of the biotic community, and 3) plant community composition in the microcosms.

The grazing amphipod caused inorganic phosphorus and nitrogen (except ammonia) levels to be elevated in the microcosms. The increase was due, at least partially, to excretion of nutrients into the water by the amphipod. The presence of H. azteca did not significantly …

Two Basic Methodological Choices In Wildland Vegetation Inventories: Their Consequences And Implications, Donald Alan Shute

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In designing inventories of wildland vegetation, two of the many basic methodological choices are: 1) whether data are collected, reduced, and stored in discrete classes or as continuous variables, and 2) whether data are gathered as general purpose variables to bear upon many questions, or as specific purpose variables optimized for only one type of prediction. The effects of these two choices on accuracy of vegetation inventories to predict plant community production were examined by comparing regression models built upon differing sets of independent variables "inventoried" from a common data base. Contrary to expectations, discrete variables of classified community types …

Changes In Spider Community Attributes Along A Subalpine Successional Gradient, Gerald Norman Waagen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The spider communities of four stages of a successional sere leading to and including spruce forests were studied in northern Utah. Four seral stages were recognized. These include: meadows, aspen (Populus tremuloides) stands, subalpine fir (Abies lasiocarpa) forest, and the climax Engelmann spruce (Pica engelmanii) forests.

During the snow-free periods of 1976, 1977 and 1978, 15,987 spiders were collected by three methods including: pitfall traps, by beating vegetation, and with sweep-net samples. Additionally, 1600 15-second intervals of behavioral observations, and measurements of 182 web locations were made.

Of 99 species collected, 44 were considered …

An Investigation Of Salinity Fluctuations In Soils Of A Northern Utah Marshland, Gary Roy Newman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ogden Bay Waterfowl Management Area is one of many marshlands bordering the Great Salt Lake that are extremely important as breeding habitats for North American waterfowl. Salinity, both of surface and interstitial waters, is an important factor in maintaining a suitable habitat within the marsh. For this reason, a study was undertaken to determine the factors affecting the salinity of surface and interstitial waters. A small (approx. 100 acre) subunit was studied extensively to determine; 1) variations in surface water salinity with flowrate and water level; and 2) variation in interstitial water salinity with depth and location within the subunit. …

Aspen-Birch Forest, Donald Rakstad, John R. Probst

Aspen Bibliography

No abstract provided.

Aspen Clearcut (8-Year), Donald Rakstad, John R. Probst

Aspen Bibliography

This report includes a breeding-bird census, a list of dominant plant species, and brief physiographic data for a 8-year old aspen clearcut on the Chippewa National Forest, Michigan.

Aspen Forest (50-Year), Connie J. Pearson, John R. Probst

Aspen Bibliography

No abstract provided.

Aerial Stand Volume Table For Plains Cottonwood In Eastern Colorado, Carleton B. Edminster, James R. Getter

Aspen Bibliography

No abstract provided.

Long-Term Changes In Cottonwoods On A Grazed And An Ungrazed Plains Bottomland In Northeastern Colorado, Glenn L. Crouch

Aspen Bibliography

No abstract provided.

Fire-Decay: Interactive Roles Regulating Wood Accumulation And Soil Development In The Northern Rocky Mountains, A. E. Harvey, M. J. Larsen, M. F. Jurgensen

Aspen Bibliography

Decay and fire play interactive roles in recycling wood and other organic materials in forest ecosystems, and contribute to the development of high quality soils in the Northern Rocky Mountains. Decayed wood, charcoal, and other decomposed organic matter are the principal media for ectomycorrhizal and nonsymbiotic nitrogen fixing microbes. The activities of these microbes are critical to the growth of forest trees. The balance between decay and fire, as it affects the amount, distribution, and type of organic matter, controls the ability of forest soils to support the growth of trees.

Estimating The Volume Of Hardwood Crowns, Stems, And The Total Tree, Douglas R. Phillips, Noel D. Cost

Aspen Bibliography

No abstract provided.

Preliminary Classification For The Coniferous Forest And Woodland Series Of Arizona And New Mexico, Earle F. Layser, Gilbert H. Schubert

Aspen Bibliography

The vegetation of southwestern United States, because of this geographic area's climatic patterns and extreme ranges in topographic relief, is complex and diverse.

Equations Predicting Primary Productivity (Biomass) Of Trees, Shrubs And Lesser Vegetation Based On Current Literature, W. Stanek, D. State

Aspen Bibliography

No abstract provided.

Feeding Preference Of Penned White-Tailed Deer For Hybrid Popular Clones, Richard L. Verch

Aspen Bibliography

No abstract provided.

Winter Diets Of Elk And Deer In The Blue Mountains, Oregon, Jon Skovlin, Martin Vavra

Aspen Bibliography

No abstract provided.

Elk-Aspen Relationships On A Prescribed Burn, Joseph V. Basile

Aspen Bibliography

No abstract provided.

Aspen Clearcut (2-Year), Connie J. Pearson, John R. Probst

Aspen Bibliography

No abstract provided.

Mature Aspen Forest, Donald Rakstad, John R. Probst

Aspen Bibliography

No abstract provided.

Aspen Forest (20-Year), Connie J. Pearson, John B. Probst

Aspen Bibliography

This report includes a breeding-bird census, a list of dominant plant species, and brief physiographic data for a 20-year old aspen forest in Ontonagon, Michigan.

A Discriminant Function Model Of Gray-Headed Junco Habitat, Andrew R. Grainger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper presents a description of gray-headed junco habitat in the form of a model based on discriminant function analysis. Junco nests were found by searching randomly located grids on a 7.8 km² study area in central Utah. Vegetation data was gathered on 500 m² circular plots surrounding nests and contrasted with similar data from searched grids where nests were not found. The model explains 28 percent of the between-groups variance and correctly classifies 68 percent of the plots.

Plant cover types are good predictors of areas where gray-headed juncos nest, while plant community type descriptions do not …

Plant Succession Studies On Subalpine Acid Mine Spoils In The Beartooth Mountains, Patricia Lea Howard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Large areas within alpine and subalpine tundra have been by disturbed by mining during this century. The most promising method for retarding deterioration of these areas is revegetation with native species through both seeding and transplants. One natural process of revegetation which occurs on portions of many existing disturbances seems to be the establishment of a few species that expand with time to form matts of plants.

At the McLaren Mine, located at 3000 m elevation in the Beartooth Mountains, Montana, active succession is occurring and is dominated by Carex species. Seed viability and successional patterns studies were conducted on …

Influence Of Spring Sheep Grazing On The Forage Intake And Quality Of Diets Consumed By Pen-Reared Mule Deer Under Winter-Range Conditions, Kenneth Owen Fulgham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the nutritional responses of mule deer during winter on range subjected to a system of spring livestock grazing. The specific purposes were 1) to determine the quality (crude protein, digestible energy, and digestibility) of diets consumed by mule deer in winter on ranges grazed and ungrazed by sheep in spring, 2) to determine the level of forage intake, as determined by the external indicator chromic oxide, for deer under the same grazing regimes, 3) to compare forage intake estimates determined by the external indicator (chromic oxide) with results obtained by ocular estimation, and 4) to determine the …

The Social Behavior Of Brown Bears At Mcneil River, Alaska, Allan L. Egbert

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The social behavior of brown bears (Ursus arctos) was studied during the summers of 1972 and 1973 as bears fished for salmon at McNeil River, Alaska. Study objectives were to determine behavioral characteristics of bears in relation to sex and age, changes in social behavior over a 40-day long fishing season, social and environmental parameters correlated with the occurrence of behavior, and to test the hypothesis that brown bears modify social behavior in a feeding aggregation to exploit a resource limited in time and space.

Over one-half of the agonistic interactions consisted of passive deferrals. Encounters that included …

The Role Of Vegetation Architecture In Determining Spider Community Organization, Cynthia L. Hatley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The relationships between vegetation architecture and spider community attributes were examined in a big sage (Artemisia tridentata) community. Spiders were separated into guilds using similarities of species' hunting behavior. Shrub architecture was experimentally manipulated in the field by either clipping 50% of a shrub's foliage to decrease foliage density or tying together a shrub's branches to increase foliage density.

Temporal patterns of spider species density, diversity (H') and evenness (J') showed midsummer peaks in both 1974 and 1975. Seasonal spider guild trends reflected the temporal prominence of a member species or genus. These temporally abundant species appeared to …

Analysis Of Ecosystem Models, Walter Dewey Valentine

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent attempts to apply frequency response analysis to compartmental models of ecosystems are flawed by the failure to define terms in an unambiguous and ecologically meaningful way, and by the failure to distinguish between information feedback and closed material loops. Analysis of the sensitivity of linear models to changes in the A matrix has shortcomings too: elements of the A matrix are often derived from more fundamental parameters and thus do not have a direct relationship to the parent model; only sensitivities to the fundamental parameters will be unconfounded and readily interpretable. A more serious problem with these techniques is …

Comparison Of Microbial Activity In Desert Soils Of The Western United States, Patricia Ann Trujillo Y Fulgham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soils from four regional deserts, Great Basin, Sonoran, Chihuahuan, and Mojave, were collected at times throughout the year which would best exhibit microbial response to moisture or vegetation. The soils were analyzed for several chemical and physical properties. Biological and biochemical characteristics, namely respiration, dehydrogenase activity, adenosine triphosphate concentration, proteolytic activity, nitrification potential, and microbial numbers, were measured.

The soils exhibited fluctuations in microbial activity as measured by respiration, dehydrogenase activity, adenosine triphosphate concentration, proteolytic activity, and nitrification potential during different moisture seasons.

Increase in soil moisture as modified by precipitation did not cause a significant difference in respiration or …

Conflict In Outdoor Recreation, Gerald R. Jacob

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The causes of conflict among users of outdoor recreation resources have received little attention from recreation researchers. Knowledge of factors responsible for conflict might assist recreation planners' attempts to reduce future instances of conflict and help management focus its conflict resolution efforts. A theory of conflict is offered as the first step in systematically procuring such knowledge. A definition and characteristics of outdoor recreation conflicts are presented; four comprehensive causes of user conflicts are proposed. Ten propositions are used to link these factors to conflict and suggest future research hypotheses. The social psychological dynamics of conflict, as described here, have …

Adaptive Significance Of Lactate Dehydrogenase B2 Isozymes In Rainbow Trout, Salmo Gairdneri And A Biochemical Genetic Comparison Of Cutthroat Trout (Salmo Clarki) Populations, Gerald Thomas Klar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rainbow trout lactate dehydrogenase (LDH) B²' B²' , B²' B²" and B²" B²" phenotypes were tested under a variety of conditions for swimming endurance, oxygen consumption rates, and blood pH, pO₂, and lactate. The B²" B²" phenotype exhibited a lower swimming endurance, under a limited oxygen supply, than the B²' B²' and B²' B²" phenotypes. Blood pH at fatigue did not differ among the LOH phenotypes that swam under low oxygen conditions (2 mg/1). …

Population Dynamics And Net Production Of Brown Trout (Salmo Trutta) In Two Areas Of A High Gradient Mountain Stream, Jeffrey C. Gosse

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Estimates of the brown trout (Salmo trutta) population were made in two areas of the Blacksmith Fork River, Cache County, Utah, from June 1972 to June 1973. Additional data were obtained on movement, growth, mortality, biomass, production, and yield.

Population density was highly variable in the area where habitat alterations had occurred, but was relatively uniform where the habitat was undisturbed. The brown trout exhibited little movement except during spawning season. Instantaneous growth and mortality rates are provided for each age group.

Mean annual biomass in the two areas was 12.0 and 10.2 grams per square meter and …