Ecology and Evolutionary Biology Commons^™

A Multiple‐Scale Assessment Of Long‐Term Aspen Persistence And Elevational Range Shifts In The Colorado Front Range, Mario Bretfeld, Scott B. Franklin, Robert K. Peet

Aspen Bibliography

Aspen forests and woodlands are some of the most species‐rich forest communities in the northern hemisphere. Changing climate, altered disturbance regimes, land use, and increased herbivore pressure threaten these forests both in Eurasia and North America. In addition, rapid mortality dubbed “Sudden Aspen Decline” is a concern for aspen's long‐term presence in the western United States, especially Colorado and Utah. Yet it is still unclear whether aspen is persistent or declining at the landscape scale. We assessed aspen persistence at different spatial scales in the Colorado Front Range by resampling 89 plots containing aspen from among 305 vegetation plots sampled …

Gibsonville Healthy Forest Restoration Project: Silviculture Report, Dan Roskopf

Aspen Bibliography

The Forest Service proposes to reduce the risk of wildfire, to protect, restore, and enhance forest ecosystem components (i.e., streams, meadows, aspen areas) in the vicinity of Gibsonville, California. A combination of hazard tree removal, forest health, and fuels reduction treatments are proposed on 1,200 acres of Forest Service system lands. These actions are proposed to be implemented on the Feather River Ranger District of the Plumas National Forest.

Nutrient Cycling In The Amazon: A Comparison Of Soil Characteristics, Insects, Root Types And Decomposition Rates Between Varzea And Terra Firme Habitats In The Ecuadorian Amazon, Mira Ensley-Field

Independent Study Project (ISP) Collection

Decomposition and nutrient cycling form the basis of every ecosystem. Nutrient availability in the soil affects plant species composition, richness, and productivity. The Amazon rainforest is known for its unusually fast nutrient cycle, but many aspects lack detailed study and analysis. This comparative study carried out in the Ecuadorian Amazon had four primary objectives related to understanding the nutrient cycle in the Amazon; 1.) analyze soil characteristics, 2.) assess insect diversity in the leaf litter layer, 3.) examine root characteristics, and 4.) measure the decomposition rate between Varzea and Terra Firme habitats alongside the Rio Napo. Forty 0.25 x 0.25m …

Effect Of Varied Disturbance Types On Dorylus (Anomma) Molestus Defensive Behavior In The West Usumbara Mountains, Tanzania., Ryan Mahar

Independent Study Project (ISP) Collection

The purpose of this study was to observe novel nest characteristics of Dorylus molestus (Siafu), as well as their defensive behavior in response to varied disturbance methods. The number of defensive soldiers at a specific section of a column was counted before and after each agitation. Varied agitation methods were used on columns without larvae presence to test how soldiers responded to different disturbance types. Disturbances on columns with larvae presence were compared to those on columns without larvae. Nest distribution, behavior, composition, and size were observed objectively. Mechanical disturbance was found to incite the greatest increase in defensive soldier …

Seagrass Community Change At Three High Risk Ports In The Great Barrier Reef World Heritage Area From 2005 To 2014, Celeste Venolia

Independent Study Project (ISP) Collection

Seagrass meadows are extremely valuable and dynamic ecosystems currently facing pressure from anthropogenic disturbances. Seagrass ecosystems are declining globally because of direct and indirect threats that shift environmental conditions controlling seagrass distribution. Seagrass species responses to disturbances vary based on a number of factors including life history strategy. The goal of this study was to map and analyze patterns of dominant seagrass species change at Cairns and Gladstone from 2005-2014 and Townsville from 2007-2014. This compilation data set was symbolized according to the life history strategy of the species. The major disturbances during this time period were physical damage from …

The Paper Trail: An Arid Connection And A Book Of A Thousand Plants, Stephen L. Young, Peter Alpert

West Central Research and Extension Center, North Platte

Following my Ph.D., I moved on to Nebraska, where as a beginning faculty member I was able to start a research program in ecology and continue to study what intrigued me most: plant competition and stress. It was during this time that I came across the paper by Peter Alpert (see his article below) and his colleagues on “Invasiveness, invasibility, and the role of environmental stress in preventing the spread of non-native plants” (Perspectives in Plant Ecology, Evolution and Systematics 3:52–66). It was an “aha” moment in reading about biological invasion research and the current consensus at that time regarding …

Invasion During Extreme Weather: Success And Failure In A Temperate Perennial Grassland, James C. Han, Stephen L. Young

West Central Research and Extension Center, North Platte

Invasive and native plant species compete for resources in similar pools, with disturbances often favoring the invader. Yet, increased climate variability may be shifting the competitive edge back toward the natives. We conducted field studies in perennial grasslands to determine the effects of clipping and drought on resource availability (light and moisture) and subsequent establishment of Carduus nutans. We measured light penetration and soil moisture content in C. nutans monoculture, clipped and non clipped grassland with C. nutans, and bare ground control plots. We also tracked phenology of the invader and grasses. Our studies revealed that light was a limiting …

The Effect Of Adjuvants At High Spray Pressures For Aerial Applications, Bradley K. Fritz, W. Clint Hoffmann, Ryan S. Henry

West Central Research and Extension Center, North Platte

Controlling droplet size is a critical part of making any successful agrochemical spray application. This is particularly true for higher-speed aerial applications where secondary atomization from air shear becomes the most dominant factor driving spray droplet size. Previous research has shown that higher spray pressures can result in larger droplet-sized sprays by increasing the exit velocity of the spray liquid from the nozzles, which in turn decreases the differential velocity between the spray liquid and surrounding airstream, reducing secondary breakup. This work explores the effects of higher-than-normal spray pressures on two typical aerial application nozzles in the presence of a …

Bigtooth And Quaking Aspen Propagation From Roots Versus Seed, Joseph M. Vande Hey

Aspen Bibliography

No abstract provided.

Developing Management Guidelines That Balance Cattle And Timber Production With Ecological Interests In The Black Hills Of South Dakota, Kurt M. Chowanski

Electronic Theses and Dissertations

Forested lands contribute to the United States (US) economy by providing livestock and timber production. Livestock grazing of forested lands has been widespread throughout the western US since the settlement era, and currently occurs on 51.4 million hectares (ha) representing 16% of all US grazing land and 22% of all US forested land (Nickerson et al. 2011). While livestock grazing and timber harvest are occurring on a substantial amount of forested land, relationships between management practices, tree stocking, timber production, forage production, livestock grazing, wildlife, aesthetics, and ecological integrity are not well documented. Whether considering timber or cattle, finding a …

High And Dry: Post-Fire Tree Seedlingestablishment In Subalpine Forestsdecreases With Post-Fire Drought Andlarge Stand-Replacing Burn Patches, Brian J. Harvey, Daniel C. Donato, Monica G. Turner

Aspen Bibliography

Aim: Climate warming and increased wildfire activity are hypothesized to catalyse biogeographical shifts, reducing the resilience of fire-prone forests world-wide. Two key mechanisms underpinning hypotheses are: (1) reduced seed availability in large stand-replacing burn patches, and (2) reduced seedling establishment/survival after post-fire drought. We tested for regional evidence consistent with these mechanisms in an extensive fire-prone forest biome by assessing post-fire tree seedling establishment, a key indicator of forest resilience.

Location: Subalpine forests, US Rocky Mountains.

Methods: We analysed post-fire tree seedling establishment from 184 field plots where stand-replacing forest fires were followed by varying post-fire climate conditions. Generalized linear …

Cattle Grazing Effects On Phragmites Australis In Nebraska, Jerry D. Volesky, Stephen L. Young, Karla H. Jenkins Pas

West Central Research and Extension Center, North Platte

Phragmites australis (common reed) is one of the most widely distributed flowering plants in North America. The introduced lineage occurs in wetland and riparian areas covering a range of climatic types. In Nebraska, an abundance of livestock could help to reduce P. australis with proper timing and grazing intensities. In 2011, a 3-yr study was initiated to evaluate targeted cattle grazing and herbicide effects and the nutritive value of this species. Treatments included a single application of imazapyr (Habitatt, BASF Corporation, Research Triangle Park, NC) herbicide applied in the first year, grazing, and a control. Grazing was applied for up …

New Verified Nonindigenous Amphibians And Reptiles In Florida Through 2015, With A Summary Of More Than 152 Years Of Introductions, Kenneth L. Krysko, Louis A. Somma, Dustin C. Smith, Christopher R. Gillette, Daniel Cueva, Joseph A. Wasilewski, Kevin M. Enge, Steve A. Johnson, Todd S. Campbell, Jake R. Edwards, Michael R. Rochford, Ryan Tompkins, Jeffrey L. Fobb, Scott Mullin, Christopher J. Lechowicz, Dallas Hazelton, Alície Warren

Papers in Herpetology

More nonindigenous species occur in Florida, USA, than any other region worldwide and may threaten many of Florida’s natural resources. The frequency of new reports mandates the need for regular updates. Herein, we use photographic and specimen vouchers in addition to literature records to provide updated information on verified nonindigenous amphibians and reptiles in Florida. Between our most recent summary in 2012 and the end of 2015, 38 additional species are known to have been intercepted (n = 2) or introduced (n = 36). We also update the invasion stage of seven species previously reported from Florida and …

Animal Welfare And Animal Rights, M.E. Rolle

Animal Sentience

This overview of Broom’s book, Sentience and Animal Welfare (2014), considers the role the book could play in the animal rights debate. In a thoroughly researched and objectively presented text, Broom lays out information that could place doubt in the minds of decision-makers. By highlighting not just the ways animals resemble humans, but also the ways humans resemble animals, Broom shines a light on a solidly grey area in the animal rights debate.

Demography And Disease Of The Rare Shrub Buckleya Distichophylla (Santalaceae) In Northeastern Tennessee, William Seth Ratliff

Undergraduate Honors Theses

Piratebush (Buckleya distichophylla (Nutt.) Torr.) is a rare, hemiparasitic shrub with the only extant populations in western North Carolina, northeastern Tennessee, and southwestern Virginia. The preferred natural hosts of piratebush, Carolina and eastern hemlocks, have seen sharp declines over the last decade due to the invasive hemlock woolly adelgid. Virginia pine, another important host of piratebush, is also susceptible to disease, specifically Cronartium appalachianum, a rust fungus for which piratebush is the secondary host. This study described and analyzed current demographic parameters of three Tennessee piratebush populations. Additionally, spatial patterns of disease and demographic characters were analyzed. These …

Evidence Of Field-Evolved Resistance To Bifenthrin In Western Corn Rootworm (Diabrotica Virgifera Virgifera Leconte) Populations In Western Nebraska And Kansas, Adriano E. Pereira, Haichuan Wang, Sarah N. Zukoff, Lance Meinke, B. Wade French, Blair Siegfried

Department of Entomology: Faculty Publications

Pyrethroid insecticides have been used to control larvae or adults of the western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, a key pest of field corn in the United States. In response to reports of reduced efficacy of pyrethroids in WCR management programs in southwestern areas of Nebraska and Kansas the present research was designed to establish a baseline of susceptibility to the pyrethroid insecticide, bifenthrin, using susceptible laboratory populations and to compare this baseline with susceptibility of field populations. Concentration-response bioassays were performed to estimate the baseline susceptibility. From the baseline data, a diagnostic concentration (LC99) was determined and …

Abejas Silvestres (Himenóptera: Apoidea) En La Neblina: Análisis De La Diversidad, Interacciones, Y Potencial Para Miel En Un Remanente De Bosque Nublado, Jen Hayes

Independent Study Project (ISP) Collection

Las abejas (Himenóptera: Apoidea) se encuentran en casi cada una de las bioregiones en el mundo. Su composición es muy diversa en los neotrópicos. Las abejas silvestres (no-Apis) representan casi el 90% de las especies de abejas en todo el mundo (Parra, 2005). Los objetivos principales de este estudio fueron realizar un inventario de las especies de abejas al final de la estación seca, observar sus interacciones intra-específicas, y determinar el potencial de producción de miel medicinal de las abejas sin aguijón (Apidae: Meliponini). El estudio fue realizado en la Reserva Inti Llacta, un remanente de bosque nublado …

Natural Gardening, Lisa Karen Miller

DLPS Faculty Publications

This presentation features methods of natural and organic gardening that preclude the use of harmful pesticides and herbicides.

Introducing Green Manures In An Organic Soybean–Winter Wheat–Corn Rotation: Effects On Crop Yields, Soil Nitrate, And Weeds, Katja Koehler-Cole

School of Natural Resources: Dissertations, Theses, and Student Research

In organic soybean– winter wheat – corn rotations, animal manure is a common choice to maintain high yields, but leguminous crops grown as green manures after wheat harvest and incorporated into the soil before corn planting, can be an alternative when animal manure is not accessible. Forage legumes with high dry matter (DM) production and high biological N fixation have been shown to meet corn N demand. However, in Eastern Nebraska, lack of precipitation can reduce green manure growth and N fixation, leading to an insufficient N supply for corn, but corn growth can also be impacted by green manure …

The Role Of Fire In Aspen Ecology And Restoration, Douglas J. Shinneman, Kevin D. Krasnow, Susan K. Mcilroy

Aspen Bibliography

Quaking aspen is generally considered to be a fire-adapted species because it regenerates prolifically after fire, and it can be replaced by more shade-tolerant tree species in the absence of fire. As early-successional aspen stands transition to greater conifer-dominance, they become increasingly fire prone, until fire returns, and aspen again temporarily dominate. While this disturbance-succession cycle is critical to the persistence of aspen on many landscapes, some aspen stands persist on the landscape without fire. The complex role of fire is an important consideration for developing conservation and restoration strategies intended to sustain aspen.

Variation In Trembling Aspen And White Spruce Wood Quality Grown In Mixed And Single Species Stands In The Boreal Mixedwood Forest, Francis De Araujo, James F. Hart, Shawn D. Mansfield

Aspen Bibliography

The Canadian boreal forest is largely represented by mixed wood forests of white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuloides Michx). In this study, a total of 300 trees originating from three sites composed of trembling aspen and white spruce with varying compositions were investigated for wood quality traits: one site was composed mainly of aspen, one mainly of spruce and a third was a mixed site. Four wood quality traits were examined: wood density, microfibril angle (MFA), fibre characteristics, and cell wall chemistry. Social classes were also determined for each site in an attempt …

Insomniac Of The Soil: A Collection Of Poetry And Essays, Sarah E. Golibart

Senior Honors Projects, 2010-2019

“Insomniac of the Soil” is a homage to a landscape that has deeply informed Sarah Golibart's life and her artistic voice – the tidewater flatlands of Virginia’s Chesapeake Bay peninsula where her family lives and where Golibart has worked on farms since high school. Both her poems and essays are earthy, imagistic, and grounded – quite literally – in the soil as well as in a sensibility of ecological ethics and sustainability. “Insomniac of the Soil” is also a love song to the fervent and fallow cycles of the soil.

Fishing For A Sustainable Future: Aquaponics As A Method Of Food Production, Richard Ramsundar

Student Theses 2015-Present

This thesis compares and explains the advantages aquaponics farming has over modern industrial intensive farming. Through a comparison natural capital usage, conservation, recycling and cost, the thesis advocates for the expansion of aquaponics usage in urban settings. The thesis also explains the history of intensive farming and aquaponics in America, the science of how aquaponics operates, the economic and environmental costs of modern intensive farming versus aquaponics farming, and the social implications of aquaponics. Lastly, I propose a policy that reallocates farm subsidies by modifying the Farm Bill. Then I propose policies that support creating a new standard of farm …

Effects Of The Developmental Environment On Oxidative Damage And Antioxidants In Red-Eared Slider Turtle ( Trachemys Scripta Elegans ) Hatchlings, Lisa Allison Treidel

Theses and Dissertations

Developmental environments influence many individual phenotypes. However, currently we have a limited understanding of how the developmental environment influences oxidative stress resistance phenotypes. Oxidative stress is defined as a physiological state during which the production of harmful free radicals exceeds the protective capabilities of antioxidants. Variations among adults in susceptibility to oxidative stress can have important consequences for life history strategies and fitness related traits. Our work was aimed at providing insight in to the role that the developmental environment plays on oxidative stress phenotypes in the model oviparous reptile the red-eared slider turtle (Trachemys scripta elegans). Here, we conducted …

Building Resilience Into Quaking Aspen Management, Paul C. Rogers

Aspen Bibliography

Throughout the 20^th century, forest scientists and land managers were guided by principles of succession with regard to aspen forests. The historical model depicted aspen as a "pioneer species" that colonizes a site following disturbance and is eventually overtopped by conifers. Aspen systems are more diverse, however, than previously described. Not only are there distinctive seral and stable aspen, but variations within these types require appropriate management considerations (Rogers et al. 2014). We recommend a strategic approach to aspen resilience that builds upon traditional aspen ecology and incorporates knowledge of varying aspen functional types, effective monitoring, historical disturbance ecology, …

Managing Ungulate Browsing For Sustainable Aspen, Samuel B. St. Clair, Paul C. Rogers, Michael R. Kuhns

Aspen Bibliography

In montane forests of the Intermountain West composition and function are often defined by what happens with quaking aspen. Aspen is a pioneer species that regenerates quickly following disturbance and then establishes ecological conditions under which the rest of the biological community develops. Quaking aspen forests have high biodiversity and provide ideal habitat for many animals. Aspen regeneration from root sprouts is highly palatable to wildlife and livestock. When browsing becomes chronic it leads to regeneration failure and eventual loss of aspen forests and associated species. Ironically, this can result in habitat and forage loss for wildlife and livestock. Here …

Stand Dynamics, Humus Type And Water Balance Explain Aspen Long Term Productivity Across Canada, Kenneth A. Anyomi, Francois Lorenzetti, Yves Bergeron, Alain Leduc

Aspen Bibliography

This study examined the relative importance of soil, stand development and climate hypotheses in driving productivity for a species that is widely distributed in North America. Inventory plots, 3548 of such, either dominated by aspen or made up of species mixture of which aspen occurs in dominant canopy position were sampled along a longitudinal gradient from Quebec to British Columbia. Site index (SI), was used as a measure of productivity, and soil, climate and stand attributes were correlated with site index in order to determine their effects on productivity. Results show a decline in productivity with high moisture deficit. Soil …

Year-End Report On Rac Project Entitled "Propagating Aspen Clones: Survival In The 21st Century", Ralph Baierlein

Aspen Bibliography

Initial damage caused by wild ungulates was minimal. In August 2013, a large elk pulled off five cones and destroyed three saplings on the exposed, eastern side of the exclosure. Although deer tracks were plentiful in the bare earth of the fire line, there was no evidence that deer had harmed the saplings. The combination of a cone and a mesh sleeve on the exposed saplings sufficed.

Physical And Biological Effects Of Modified Polysorbate 20, Kevin Penfield, Bryan Young, Julie K. Young, Greg R. Kruger, Ryan Henry, Greg Lindner

West Central Research and Extension Center, North Platte

Three experimental polyoxyethylene sorbitan monolaurate derivatives were synthesized with molecular fingerprinting techniques applied to experimental materials, confirming the target compounds had been produced. Chemical property measurements were compiled that aligned with theoretical predictions and physical property measurements confirmed their intentional differences yielded the anticipated changes in surfactant behavior. Imidacloprid uptake data confirmed penetration of leaf cuticles was enhanced in the presence of polyoxyethylene sorbitan monolaurates with several experimental materials providing uptake equivalent to reference material. Select materials were included in field and greenhouse trials where observations included good biological response with a range of individual herbicides as well as improved …

Corn Residue Stocking Rate Affects Cattle Performance But Not Subsequent Grain Yield, L. A. Stalker, Humberto Blanco-Canqui, Jennifer A. Gigax, A. L. Mcgee, T. M. Shaver, S. J. Van Donk

West Central Research and Extension Center, North Platte

This study investigated effects of stocking rate on cattle performance, quality and quantity of corn residue, and impact of residue removal on grain yield for 5 yr at the University of Nebraska – Lincoln West Central Water Resources Field Laboratory near Brule, NE. Four removal treatments—1) no removal (control), 2) grazing at 2.5 animal unit month (AUM)/ ha, 3) grazing at 5.0 AUM/ha, and 4) baling—were applied to a center pivot–irrigated corn field (53 ha). The field was divided into eight 6.6-ha paddocks to which replicated treatments were assigned. Samples of residue were collected in October and March (before and …