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Full-Text Articles in Life Sciences

Ponderosa Pine Mortality And Bark Beetle-Host Dynamics Following Prescribed And Wildland Fires In The Northern Rocky Mountains, Usa, Ryan Stephen Davis May 2008

Ponderosa Pine Mortality And Bark Beetle-Host Dynamics Following Prescribed And Wildland Fires In The Northern Rocky Mountains, Usa, Ryan Stephen Davis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ponderosa pine delayed mortality, and bark beetle attacks and emergence were monitored on 459 trees for 3 years following one prescribed fire in Idaho and one wildland fire in Montana. Resin flow volume (ml) was measured on 145 fire-injured ponderosa pine 2 and 3 years post-fire. Logistic regression was used to construct two predictive ponderosa pine mortality models, and two predictive bark beetle-attack models. Post-fire delayed tree mortality was greater with the presence of primary bark beetles independent of diameter at breast height (DBH) (cm), and was greater in smaller diameter trees most likely due to direct effects of fire-caused …


Comparison Of Water Dynamics In Aspen And Conifer: Implications For Ecology Water Yield Augmentation, Eric Martin Lamalfa May 2007

Comparison Of Water Dynamics In Aspen And Conifer: Implications For Ecology Water Yield Augmentation, Eric Martin Lamalfa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Differences in water dynamics between deciduous aspen (Populus tremuloides) and co-occurring evergreen conifer species in the Northern Rocky Mountains result from complex physical and biological interactions. A comprehensive evaluation of individual water transfer mechanisms was used to elucidate the relative importance of several components of the hydro logic cycles of aspen and conifer, and determine which water transfer mechanisms have potential to cause differences in net water yield.

Adjacent aspen and conifer stands were monitored to determine snow accumulation and ablation (snow survey), soil moisture recharge (capacitance probes), snowpack sublimation (sublimation pan), transpiration period (thermal dissipation probes), and …


Greenstrip Establishment And Management In The Intermountain West, Brenda Kristine Younkin-Kury May 2004

Greenstrip Establishment And Management In The Intermountain West, Brenda Kristine Younkin-Kury

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greenstrips were established at two sites in Utah to determine if seeded, grazed cool-season, perennial grasses would change fire behavior characteristics in areas currently dominated by Bromus tectorum. Frequency data were collected for both grazed and ungrazed seeded species and resident weed species. Moderate spring grazing did not negatively impact the establishment of seeded species at Camp Williams. Grazing at Promontory Point decreased Agropyron desertorum frequency and increased the frequency of Pascopyrum smithii. Biomass data collected for grazed and ungrazed treatments in both years indicated that moderate spring or winter grazing the first two years of establishment did …


Remote Sensing Of Sagebrush Community Structural Patterns Across Scales, Lisa A. Langs May 2004

Remote Sensing Of Sagebrush Community Structural Patterns Across Scales, Lisa A. Langs

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Throughout the Intermountain West there has been a substantial reduction in both the quantity and quality of sagebrush ecosystems. To assist current range management objectives, numerous efforts have been made to classify and map sagebrush communities using remotely sensed data. However, the amount of detail provided by these broad-scale mapping projects is often limited. This research evaluated the ability of a suite of airborne and satellite imagery to detect sagebrush community structural attributes, specifically percent canopy cover, live cover, density, size-vigor, and spatial arrangement of shrubs. Field data was collected at Camp Williams National Guard Training Facility near Bluffdale, Utah, …


Quantifying Losses Of Understory Forage In Aspen Stands On The Dixie And Fishlake National Forests, Barton R. Stam May 2004

Quantifying Losses Of Understory Forage In Aspen Stands On The Dixie And Fishlake National Forests, Barton R. Stam

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The West has lost up to 60% of its historic aspen stands over the last century, probably as a result of the successional tendency of aspen to be replaced by coniferous species in the absence of periodic fires. One of several major impacts of this change is the loss of understory forage as conifer canopy cover increases. I measured understory biomass in aspen stands ranging from 0% to 81 % absolute conifer cover in the canopy and found that understory production declines exponentially as conifers replace aspen. I also did an economic analysis to determine the value of the forage …


Snow Avalanche Disturbance In Intermountain Spruce-Fir Forests And Implications For The Spruce Bark Beetle (Coleoptera: Scolytidae), Elizabeth G. Hebertson May 2004

Snow Avalanche Disturbance In Intermountain Spruce-Fir Forests And Implications For The Spruce Bark Beetle (Coleoptera: Scolytidae), Elizabeth G. Hebertson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Spruce beetle outbreaks are the primary biotic disturbance affecting forests in the Intermountain spruce-fir zone. Major snow avalanches can produce large quantities of host material for spruce beetle colonization; however, few studies have examined the influence of avalanche disturbance on outbreak initiation. The purpose of my research was to investigate potential relationships between these two disturbance agents. In the first study, I used dendro-ecological analyses to date major avalanche years on the Wasatch Plateau in south-central Utah, and then determined what climate factors were associated with avalanche occurrence. The results indicated that mean January snowfall was significantly related to the …


Cougar Exploitation Levels In Utah: Implications For Demographic Structure, Metapopulation Dynamics, And Population Recovery, David C. Stoner May 2004

Cougar Exploitation Levels In Utah: Implications For Demographic Structure, Metapopulation Dynamics, And Population Recovery, David C. Stoner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Presently, eleven western states and two Canadian provinces utilize sport hunting as the primary mechanism for managing cougar (Puma concolor) populations. However, the impacts of sustained harvest on population dynamics and demographic structure arc not well understood. Additionally, the lack of cost-effective enumeration techniques and strongly conflicting societal values complicate effective management of this species. Given these concerns, the primary goals of this study were (I) to determine the effects of sustained harvest on cougar populations, and (2) estimate the level and extent of cougar harvest statewide.

I monitored cougar populations on Monroe Mountain in south-central Utah, and …


Species Pairwise Associations Over Nine Years Of Secondary Succession: Assessing Alternative Explanations And Successional Mechanisms, Lara R. Rozzell May 2003

Species Pairwise Associations Over Nine Years Of Secondary Succession: Assessing Alternative Explanations And Successional Mechanisms, Lara R. Rozzell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The importance and mechanisms of species interactions are undetermined in most successional systems. I used correlations and null modeling to detect pairwise species associations between 33 plant species in the first nine years of secondary succession after logging and burning in a western Oregon Cascade forest. I tested for correlations between each species and soil nutrients, nonvegetative ground cover, and surrounding vegetation. More positive than negative associations were found at all sampling times. The proportion of positive associations decreased and negative associations increased through time. Up to 42% of associations at a sampling time were explicable by shared positive correlations …


Catastrophic Wildfire Hazard Assessment In Pinyon-Juniper Woodlands Utilizing A Managerial Paradigm, Benjamin D. Baldwin May 2003

Catastrophic Wildfire Hazard Assessment In Pinyon-Juniper Woodlands Utilizing A Managerial Paradigm, Benjamin D. Baldwin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The impetus for this research was the increasing threat of catastrophic wildfires resulting from the accumulation of fuels across the West. Guided by the priorities, goals, and guiding principles outlined by the national fire plan (NFP), the objective was to identify those areas within a pinyon-juniper woodland-dominated landscape with the highest hazard of catastrophic wildfire. The intent was to help managers prioritize proactive fuels management efforts outside of the wildland urban interface (WUI). Based on a management paradigm, constraints were placed on the data collection, analysis, and model development. A geographic information system (GIS) was used to create a hazard …


Restoration Of Aspen In Different Stages Of Mortality In Southern Utah, Seth Ray Ohms May 2003

Restoration Of Aspen In Different Stages Of Mortality In Southern Utah, Seth Ray Ohms

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Aspen clones of an aspen-dominated community in Southwestern Utah are declining, some having experienced high mortality coupled with in sufficient regeneration. The objectives of this study were to (I) determine if decadent, non-regenerating mature aspen stands could be regenerated through disturbance of the 111 auxin/cytokinin hormone relationship by clearcutting; (2) determine the extent of ungulate use of regenerating aspen ramets. Clearcuts were made in late summer of 2001 in 10 different clones that exhibited various levels of decline on a continuum from relatively healthy to extremely deteriorated. Nested wildlife/livestock exclosures were constructed in each clearcut plot, as well as in …


A Conceptual Model To Characterize Internal Structure Of Plant Communities Based On Functional Traits In Camp Williams, Utah, And Camp Grayling, Michigan, Patricia Hernandez De La Rosa May 2002

A Conceptual Model To Characterize Internal Structure Of Plant Communities Based On Functional Traits In Camp Williams, Utah, And Camp Grayling, Michigan, Patricia Hernandez De La Rosa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

How plants from a common species pool form community has been considered from a variety of approaches. A promising approach involves the search for assembly rules based on plant functional traits. This approach has potential to provide insight into community and ecosystem processes In this research. a general and simple conceptual model based on life forms and independent of species is used as a framework for assessing the internal structure of plant communities. Plant functional traits are used to identify patterns within and between plant communities in the contrasting environments of Camp Williams, Utah, and Camp Grayling, Michigan.

The conceptual …


Ecology Of Treeline Whitebark Pine (Pinus Albicaulis) Populations In Central Idaho: Successional Status, Recruitment, And Mortality, And A Spring Temperature Reconstruction From Whitebark Pine Tree Rings, Dana Lee Perkins May 2001

Ecology Of Treeline Whitebark Pine (Pinus Albicaulis) Populations In Central Idaho: Successional Status, Recruitment, And Mortality, And A Spring Temperature Reconstruction From Whitebark Pine Tree Rings, Dana Lee Perkins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigated the successional status of treeline whitebark pine (Pinus albicaulis) populations on 14 stands in central Idaho and used empirical statistical models to determine the principal factors affecting recruitment and mortality. The longest lived whitebark pines from four additional high-elevation sites were used to develop a tree-ring chronology to reconstruct over 1,000 years of average April-May temperature.

The assessment of stand structures using size-frequency distributions generally provides evidence that treeline whitebark pine populations are currently self-sustaining in areas of low to nonexistent incidence of white pine blister rust (Cronartium ribicola). However the presence of …


Economic Impact Of Snowmobiling In Utah, Ikuko Fujisaki May 2001

Economic Impact Of Snowmobiling In Utah, Ikuko Fujisaki

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to estimate statewide and local economic impact resulting from snowmobiling activities in Utah to gain a better understanding of preferences and opinions of Utah snowmobilers. The results will provide valuable information for snowmobiling management.

The survey instrument was designed to describe trip behavior, snowmobiling-related trip and annual expenditures, level of satisfaction with Utah snowmobiling opportunities, and demographics. A telephone survey was conducted with randomly selected households with registered snowmobiles during the period from April to June 2000. A 54.5% response rate yielded 373 usable completed questionnaires for data analysis.

For economic impact analysis, an …


An Investigation Of The Cone And Seed Insects Of Whitebark Pine And Alpine Larch Emphasizing The Western Conifer Seed Bug (Hemiptera: Coreidae) And The Larch Cone Fly (Diptera: Anthomyiidae), Laurel K. Anderton May 2000

An Investigation Of The Cone And Seed Insects Of Whitebark Pine And Alpine Larch Emphasizing The Western Conifer Seed Bug (Hemiptera: Coreidae) And The Larch Cone Fly (Diptera: Anthomyiidae), Laurel K. Anderton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Laboratory and field feeding tests with Leptoglossus occidentalis Heidemann proved that both immature and mature seed bugs can use cones and foliage of whitebark pine, Pinus albicaulis Engelmann, as a food source for 1- to 2-week periods. Damage to unprotected whitebark pine cones by seed bugs ranged from 0.3 to 2.1 % of seeds per cone, and for bagged cones averaged 0.7% of seeds per cone. Total insect damage ranged from 0.4 to 7.2% of seeds per cone. A seed chalcid, Megastigmus sp., was documented for the first time on whitebark pine and damaged 4.7% of examined seeds at one …


Local Teacher Suggestions And Evaluations Of The Allen And Alice Stokes Nature Center School Group Programs, Jennifer E. Desarro May 1999

Local Teacher Suggestions And Evaluations Of The Allen And Alice Stokes Nature Center School Group Programs, Jennifer E. Desarro

Undergraduate Honors Capstone Projects

Environmental education is becoming more prevalent in school curriculums. The Tbilisi Declaration of 1977 defines environmental education as:

A process aimed at developing a world population that is aware of, and concerned about, the total environment and its associated problems, and which has the knowledge, attitudes, skills, motivation, and commitment to work individually and collectively toward solutions of current problems and the prevention of new ones (Braus and Wood, p.6).

By incorporating more environmental education into elementary and middle school curriculums, the students are becoming more prepared to deal with problems and make educated choices affecting their futures.


A Survey Of The General Public Assessing Public Attitudes Toward Animal Damage Control Management Policy, Douglas K. Reiter May 1999

A Survey Of The General Public Assessing Public Attitudes Toward Animal Damage Control Management Policy, Douglas K. Reiter

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A mail survey of randomly selected stratified U.S. households assessed general attitudes toward wildlife and specific concerns about wildlife damage management and the federal Animal Damage Control program. Respondents strongly supported federal government's role in ensuring public safety, engaging in public education, and continuing research into nonlethal control methods. Weaker support was found for lethal control of predators and crop depredators, and financial compensation for losses due to wildlife activities was generally opposed. Lethal methods of control were generally considered to be inhumane and nonlethal methods humane. When asked to rank the importance of factors to be considered when selecting …


Multi-Scalar Spatial Modeling Of Northern Forest Dynamics: Foundations, Theories, And Applications, Don C. Bragg May 1999

Multi-Scalar Spatial Modeling Of Northern Forest Dynamics: Foundations, Theories, And Applications, Don C. Bragg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This dissertation describes the development and analysis of a new forest dynamics model. The NORTHern Woodland Dynamics Simulator (NORTHWDS) was designed to spatially model forest pattern and process for the northern Lake States, and to incorporate multiple spatial scales. While ecologically detailed, this stand table-based model is sufficiently parsimonious to be able to simulate 100s to 1000s of hectares for centuries. Processes like tree regeneration, growth, and mortality, herbaceous and shrubby competition, biogeochemistry, carbon cycling, edge effects, and climatic influences are incorporated in NORTHWDS. Wind disturbance and white-tailed deer browsing were also included …


Utah's Rural Communities: Planning For The Future, Judith A. Kurtzman May 1999

Utah's Rural Communities: Planning For The Future, Judith A. Kurtzman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two of the biggest concerns facing communities in the Intermountain West are the dichotomies of rapid growth and development as opposed to economic decline and stagnation. Numerous strategies have been developed by social and economic scientists to help communities manage the many problems associated with these concerns. One strategy recommended by many researchers and used by numerous communities to stabilize their economies is economic diversification. For many rural communities in Utah, tourism and recreation have been used as part of that diversification effort. Recreation and tourism also play a role in the dichotomies of rapid growth and development by often …


A Geographic Information System Assessment Method For Fire Management: Identifying Fire Danger Areas, Richard D. Stratton May 1998

A Geographic Information System Assessment Method For Fire Management: Identifying Fire Danger Areas, Richard D. Stratton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In partnership with the USDA Forest Service and the Utah Division of Forestry, Fire, and State Lands, a geographic information system (GIS) was used to create a wildland fire assessment methodology. GIS layers (or themes) include topography, infrastructure, vegetation, climate, "sensitive" natural values, and fire history. Two phases of assessment are presented: a preliminary analysis designed for planning use at the landscape level, and a detailed analysis for site-specific use.

Results of the phase 1 assessment are density grids delineating areas of high fire occurrence and suggesting to managers where a phase 2 assessment is needed. By using the environmental, …


Development And Validation Of Forest Habitat Models In The Uinta Mountains, Utah, Tracey S. Frescino May 1998

Development And Validation Of Forest Habitat Models In The Uinta Mountains, Utah, Tracey S. Frescino

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A significant question currently facing environmental managers is how to accurately and efficiently quantify forest diversity and resources. Numerous studies have demonstrated the use of modern spatial analytical tools, such as geographical information systems (GIS), remote sensing devices, and statistical models for predicting the distribution of dominant vegetation cover types. This study examines the ability of generalized additive models (GAMs) to delineate structural diversity in forested ecosystems (specifically the Uinta Mountain Range in Utah) using GIS tools and satellite spectral data, and analyzes the effect of including different forms of satellite data in model construction (i.e., Landsat thematic mapper (TM), …


Fuels Inventory And Appraisal In Intermountain Quaking Aspen (Populus Tremuloides) Communities, Janet A. Beales May 1998

Fuels Inventory And Appraisal In Intermountain Quaking Aspen (Populus Tremuloides) Communities, Janet A. Beales

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Field research was conducted in quaking aspen, Populus tremuloides Michx., communities. Fifty-one plots were established in seven major locations in the Bear River Range of northern Utah. The locations inventoried were divided into two age classes: young aspen (under 70 yr) and old aspen (over 70 yr). Custom fuel models were developed for each age class and the data were analyzed for relationships between fuel loads and other measurable factors, including: basal area, average diameter at breast height (d.b.h.), fuel depth, litter loads, tree regeneration, shrub loads, herbaceous loads, slope, tree height, aspect, percent aspen in the plot, grazing intensity, …


Relationship Between Teton Science School Programs And Teachers' Ability To Teach About The Environment, Jennifer A. Levy May 1998

Relationship Between Teton Science School Programs And Teachers' Ability To Teach About The Environment, Jennifer A. Levy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents an analysis of 1996/97 survey research data regarding the relationship between three types of Teton Science School (TSS) programs and classroom teachers ' ability to teach about the environment. Based on observations by resident instructors and faculty at TSS, three research questions were developed. The primary objective of the research questions was to consider the relationship between TSS residential education programs and participating teachers' ability to teach about the environment.

Analyses are based on comparing descriptive statistics of teachers who have participated in one of the three types of TSS programs or a combination of the three …


Aspen Regeneration And Response To Fire In The Intermountain West, Kelly J. Mccloskey May 1998

Aspen Regeneration And Response To Fire In The Intermountain West, Kelly J. Mccloskey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The history of Populus tremuloides regeneration in the Intermountain West, particularly western Wyoming, is one of prolific vegetative reproduction following wildland fire. The reproductive physiology of aspen and its disturbance-response characteristics are explored through a review of previous studies. The combination of fire suppression and increased herbivory on aspen by wild and domestic ungulates is likely facilitating conifer invasion of areas historically dominated by aspen as has been observed in parts of Wyoming, Utah, and Colorado over the past 100 years. A case study of the regenerative response of aspen to wildland fire in western Wyoming demonstrates how physiology, life …


Grassroots Of The Desert: An Analysis Of The Roles Of The Utah Wilderness Association And The Southern Utah Wilderness Alliance In The Debate Over Wilderness Designation Of Bureau Of Land Management Lands In Southern Utah, Amy E. Brennan May 1998

Grassroots Of The Desert: An Analysis Of The Roles Of The Utah Wilderness Association And The Southern Utah Wilderness Alliance In The Debate Over Wilderness Designation Of Bureau Of Land Management Lands In Southern Utah, Amy E. Brennan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The battle over federal Wilderness designation of Bureau of Land Management lands in southern Utah has entered its third decade. Throughout this lengthy debate numerous stakeholders have maintained involvement, including members of Utah's conservation community. Two of the most prominent wilderness advocacy groups in Utah are notable not only for their sustained involvement with the issue, but also for their divergent positions on how to resolve this public land dispute. This research examines those two organizations, the Utah Wilderness Association and the Southern Utah Wilderness Alliance, through an analysis of their respective structural, organizational, philosophical, and tactical perspectives.

Ultimately, the …


Effectiveness Of Grid Systems For Pheromone-Trapping Sparse Gypsy Moth Populations In Mountainous Terrain In The Intermountain West, Colleen Keyes May 1997

Effectiveness Of Grid Systems For Pheromone-Trapping Sparse Gypsy Moth Populations In Mountainous Terrain In The Intermountain West, Colleen Keyes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two field experiments determined an effective intertrap distance (ITD) for early detection and delimitation sparse gypsy moth (Lepidoptera: Lymantriidae, Lymantria dispar L.) populations in mountainous terrain. This study found that current Animal and Plant Health Inspection Service trapping guidelines are not sufficient for early detection of small gypsy moth populations in mountainous terrain. Detection trapping in mountainous terrain should have an ITD of not more than 804 m. Delimiting trapping should use a grid design with an ITD of 152 m.

A related study determined natural adult male mortality in the climate of the intermountain West, which includes Utah, Nevada, …


Delineation Of Ecological Units For The Ashley National Forest, At The Landscape Level, Using Classification Tree Modeling, Teresa H. Swiatek May 1997

Delineation Of Ecological Units For The Ashley National Forest, At The Landscape Level, Using Classification Tree Modeling, Teresa H. Swiatek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study integrated remotely sensed data, geographic information system (GIS), and classification tree-based modeling to delineate ecological units for the Ashley National Forest. Data points, provided by the Ashley National Forest, with a known location and dominant vegetation type, were related to data layers that were determined to be helpful in a landtype classification. These layers included elevation, slope, aspect, potential solar irradiation, precipitation, geology, basins, Landsat thematic mapper (TM) bands 3, 4, 5, and 6, and basic land cover. These points, with their related information, were then used to train the tree-based model for landtype classification. This resulted in …


Bark Beetle Activity In Douglas-Fir, Pseudotsuga Menziesii Var. Glauca Mirb. (Franco), Following The 1994 Beaver Mountain Fire, Catherine A. Cunningham May 1997

Bark Beetle Activity In Douglas-Fir, Pseudotsuga Menziesii Var. Glauca Mirb. (Franco), Following The 1994 Beaver Mountain Fire, Catherine A. Cunningham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The 1994 Beaver Mountain fire ignited the canopies of subalpine fir, Abies lasiocarpa, and spread ground fire into adjacent Douglas-fir forests, Pseudotsuga menziesii var. glauca. Despite shorter flight seasons due to lower annual temperatures and persistent snow, the Douglas-fir bark beetle, Dendroctonus pseudotsugae Hopkins, attacked a range of moderately fire-injured host conifers. Logistic regression models illustrated that in 1995 associated bark beetles selected large diameter Douglas-fir with 60-80% bole char, 60-80% crown volume scorch, and 50-70% probability of mortality due to fire. In 1996 beetle preference shifted to smaller diameter trees with lighter fire injury. Tree size was …


Litter Decomposition And Nutrient Release Patterns In A Subalpine Forest In Northern Utah, Amber Denton Johnson May 1997

Litter Decomposition And Nutrient Release Patterns In A Subalpine Forest In Northern Utah, Amber Denton Johnson

Undergraduate Honors Capstone Projects

In the arid subalpine zone of the intermountain west it is common to see patchy forests interspersed with open meadows containing scattered clusters of trees referred to as tree islands. These tree islands are often composed of subalpine fir [Abies lasiocarpa (Hook) Nutt.] and Englemann spruce [Picea englemannii (Parry)]. In desert ecosystems, where lack of water is the most important factor limiting growth and nutrient dynamics, it is not unusual to see individual plants (especially in the shrub community) creating "islands of fertility", in which the plants collect nutrients by pumping them from deeper in the soil profile and redepositing …


Land Degradation And Desertification In Arid And Semiarid Regions, Youssef Bahddou May 1996

Land Degradation And Desertification In Arid And Semiarid Regions, Youssef Bahddou

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Definitions of desertification have been numerous and the subject of hot debate. The definition proposed in 1991 by United Nations UNEP's Desertification Control/Programme Acting Centre (DC/PAC) was "land degradation in arid, semiarid and dry sub-humid areas resulting mainly from adverse human impact". This definition incorporates a number of processes which lead to the impoverishment of soils and vegetation, where human activity has been the main contributory factor. Examples include the loss of organic matter, increase in soil bulk density, decrease in infiltration, high levels of erosion, dunes formation, salinization, and compaction and displacement of top soil. The definition noted above …


Effectiveness Of Carbaryl And Pyrethroid Insecticides For Protection Of Engelmann Spruce From Attack By Spruce Beetle (Coleoptera: Scolytidae), Karen J. Johnson May 1996

Effectiveness Of Carbaryl And Pyrethroid Insecticides For Protection Of Engelmann Spruce From Attack By Spruce Beetle (Coleoptera: Scolytidae), Karen J. Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A field experiment tested the effectiveness of carbaryl and two pyrethroid insecticides, cyfluthrin and esfenvalerate, in protecting high-value Engelmann spruce trees from attack by Dendroctonus rufipennis Kirby. Carbaryl suspension at the 2% registered rate and a reduced rate of 1 % were both effective in protecting Engelmann spruce from attack by D. rufipennis through two pheromone baiting periods and 24 months following insecticide application. Cyfluthrin at 0.025% rate and esfenvalerate at 0.025 and 0.05% rates provided effective protection through one pheromone baiting and 12 months following insecticide application. Only cyfluthrin at 0.008% rate was judged ineffective protection 12 months following …