Terrestrial and Aquatic Ecology Commons^™

A Desert In Disguise: The Resilience Of The Nebraska Sandhills, Jeff Hartman

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

The Nebraska Sandhills are the largest sand dune system in the Western Hemisphere, and are unique because they remain relatively undisturbed from row crop agriculture. Research in the past two decades demonstrated that the Sandhills are dynamic on millennial timescales, switching between stabilized, vegetated states to non-vegetated, mobilized states. The Sandhills are currently stabilized, but understanding how ecological processes are altered as sand dunes transition from stabilized to mobilized states, provides insight into the thresholds, stability, and resilience of this grassland ecosystem. My research investigated the impacts of vegetation disturbances on ecological processes and the sand dune surface stability. For …

Expansion Of The Chlorovirus Genus By Studies On Virus Natural History And Chlorella Host Metabolism, Cristian F. Quispe

School of Biological Sciences: Dissertations, Theses, and Student Research

Inland waters cover about 2.5 percent of our planet and harbor huge numbers of known and unknown microorganisms including viruses. Viruses likely play dynamic, albeit largely undocumented roles in regulating microbial communities and in recycling nutrients in the ecosystem. Phycodnaviruses are a genetically diverse, yet morphologically similar, group of large dsDNA-containing viruses (160- to 560-kb) that inhabit aquatic environments. Members of the genus Chlorovirus are common in freshwater. They replicate in eukaryotic, single-celled, chlorella-like green algae that normally exist as endosymbionts of protists in nature. Very little is known about the natural history of the chloroviruses and how they achieve …

Occupancy Analysis And Density Estimation Of Kori Bustards (Ardeotis Kori) And Helmeted Guineafowl (Numida Meleagris) For Use In Landscape Conservation Planning In The Northern Tuli Game Reserve, Botswana, Kathryn R. Mccollum

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

For understudied species, more informed conservation planning and decision-making on both the local and landscape levels may be attained through the use of occupancy and abundance estimations. Here, we focus on two iconic bird species in eastern Botswana, kori bustards (Ardeotis kori) and helmeted guineafowl (Numida meleagris). The overall goal of this project was to better understand the hierarchy of factors that influence occupancy (ψ) and density of kori bustard and helmeted guineafowl populations within the Northern Tuli Game Reserve and how these factors may interact to affect landscape conservation and usage. We performed distance sampling …

Effects Of Wind Turbine Noise On Male Greater Prairie-Chicken Vocalizations And Chorus, Cara E. Whalen

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

Wind energy facilities are constructed without full knowledge of their effects on birds, and the noise generated by wind turbines is a particular concern. I investigated the effects of wind turbine noise on male Greater Prairie-Chicken (Tympanuchus cupido pinnatus) vocalizations and chorus near Ainsworth, NE, USA in 2013 and 2014. I studied 14 leks located in the area surrounding a 36-turbine wind energy facility. I used two main approaches in this study. First, I recorded Greater Prairie-Chicken boom, cackle, whine, and whoop vocalizations at each of the study leks and measured the duration, sound pressure level, peak frequency, …

When An Invasive Plant Fails To Invade, Stephen L. Young

West Central Research and Extension Center, North Platte

In 2012, much of the US Midwest was gripped in one of the most severe droughts on record. While conducting experimental fieldwork at a site in Nebraska during June of that year, I noticed a single musk thistle (Carduus nutans; Figure 1) that appeared to be in the bolt or early flowering stage, which is typical for the species at that time. Here, however, two things were unusual: this plant was less than 1 meter tall (with adequate moisture and light, musk thistle typically grows to heights of 1–2.5 meters before flowering), and was only 3 months old (the bolt …

Spreading Holiday Spirit And Northwestern Salamanders, Ambystoma Gracile (Baird 1859) (Caudata: Ambystomatidae), Across The Usa, Michael R. Rochford, Jeffrey M. Lemm, Kenneth Krysko, Louis A. Somma, Robert W. Hansen, Frank J. Mazzotti

Papers in Herpetology

Introduced species of amphibians and reptiles are of growing conservation concern (Bury and Luckenbach 1976; Krysko et al. 2011; Meshaka 2011). Unintentional introductions result largely from individuals escaping from enclosures or hitch-hiking in cargo or on vehicles, whereas intentional introductions occur primarily because a species is perceived to be of value to humans or from deliberately releasing sick or unwanted animals, including pets (Kraus 2009; Krysko et al. 2011). In Florida, most known introductions are directly related to the pet trade, but about 12% are related to the cargo pathway (Krysko et al. 2011). In this paper, we report the …

Resilience Thinking And Structured Decision Making In Social-Ecological Systems, Noelle M. Hart

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

Natural resource management may be improved by synthesizing approaches for framing and addressing complex social-ecological issues. This dissertation examines how structured decision making processes, including adaptive management, can incorporate resilience thinking. Structured decision making is a process for establishing a solid understanding of the problem, values, management options, and potential consequences. Adaptive management is a form of structured decision making in which uncertainty is reduced for iterative decisions through designed monitoring and review. Resilience thinking can help conceptualize complex social-ecological systems and draws attention to the risks of managing for narrowly-focused objectives.

This dissertation provides practical advice to managers and …

Discovery And Delimitation: Criconematid Nematodes Of North American Grasslands, Magdalena Jean Olson

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Approximately 200 years ago, North American landscapes were dominated by vast expanses of grassland. The Great Plains, an ecologically complex and diverse ecoregion, extended from Canada to the Gulf of Mexico, and from the Rocky Mountains to the border of the eastern hardwood forest in Indiana. Now the original tallgrass prairie exists in small widely dispersed remnant patches surrounded by agroecosystems. This study is an effort to characterize soil nematode diversity and population structure within those remnant patches. The plant parasitic nematode family Criconematidae serves as our indicator for nematode diversity, due to its global distribution, high abundance in natural …

Mammalian Records From Southwestern Kansas And Northwestern Oklahoma, Including The First Record Of Crawford’S Desert Shrew (Notiosorex Crawfordi) From Kansas, Cody A. Dreier, Keith Geluso, Jennifer D. Frisch, Brittney N. Adams, Alyx R. Lingenfelter, Anthony E. Bridger, Patricia Freeman, Cliff Lemen, Jeremy A. White, Brett R. Andersen, Hans W. Otto, Curtis J. Schmidt

School of Natural Resources: Faculty Publications

Mammalian distributions are constantly changing. Some distributional shifts reflect habitat change, climate change, and human transplantations; thus, such shifts are due to actual expansions or contractions of populations. However, other species ranges that appear to shift as the result of new records being added to known distributional limits actually might reflect populations that previously were undetected due to a lack of past surveys or species that are difficult to detect. In 2013, multiple techniques were employed to document mammalian distributional records in southwestern Kansas and northwestern Oklahoma. We discovered three new county records in Morton County, Kansas (Crawford’s Desert Shrew, …

Carbon Storage Potential Of Windbreaks On Agricultural Lands Of The Continental United States, William Ballesteros Possu

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

Agricultural production systems face major challenges under climate change scenarios in terms of expected negative impacts on productivity and persistence of the crops. Greenhouse gases from agriculture continue to rise although not as fast as from other fossil fuel-based human activities. Windbreaks perform several ecosystems functions that improve the local and regional capacity of crop systems to increase yields and offer environmental services by minimizing the negative effects of extreme weather events. Windbreaks also represent an important means of mitigating greenhouse gas emissions. This is predominantly accomplished by the windbreak trees storing carbon (C) in their above and belowground woody …

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 …

Bioenergetics And Habitat Suitability Models For The Chinese Mystery Snail (Bellamya Chinensis), Danielle M. Haak

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

Relatively little is known about the invasive Chinese mystery snail (Bellamya chinensis). This research aims to elucidate some of the mystery surrounding this species. First, we place the species in context with other invasive freshwater snails of the USA and Canada, identifying current information gaps, categorizing shared characteristics among families and species, and comparing functional roles and ecological effects of freshwater snails. We conclude that more focus needs to be directed to regulating the aquarium, pet, and food trades if we are serious about preventing future invasions. Next, we develop a bioenergetics model for the species by quantifying …

Ecology And Management Of Superabundant Fish Populations, Nathaniel T. Stewart

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

Fish population biomasses can reach extreme levels; we term these populations superabundant fish populations. Superabundant fish populations may negatively affect aquatic communities and anglers, necessitating the effective management of the superabundant fish populations. However, there are gaps in our understanding of these populations. The gaps in our understanding hamper our ability to predict effects on valuable sportfisheries and to effectively manage superabundant fish populations. The overall goal of my thesis research is to provide further insight into the ecology of superabundant fish populations and to provide information that will aid in their effective management. First, we described a new method …

Plant Diversity Affects Performance Of Invasive Thistles In Restored Nebraska Grasslands, Katilyn J. Price

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

Invasive plant species threaten native grasslands, affecting nutrient cycling, biodiversity, wildlife habitat, and usable land for production. Consequently, preventing establishment of invasive species is critical before removal becomes difficult and expensive. The purpose of this study was to examine the effects of grassland plant diversity on musk thistle (Carduus nutans) and Canada thistle (Cirsium arvense) establishment and determine which environmental factors (light penetration, soil moisture, plant diversity, and soil nitrogen) account for resistance to invasions. In a field experiment at The Nature Conservancy’s Wood River site (Nebraska), the two invasive thistle species were planted into replicated …

Soil Preferences Of Nicrophorus Beetles And The Effects Of Compaction On Burying Behavior, Kelly A. Willemssens

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

The American burying beetle, Nicrophorus americanus Olivier was declared federally endangered in 1989 and many efforts to prevent this species from going extinct are ongoing. The Nicrophorus beetles bury small carcasses for reproductive purposes. They also reside in the soil during times of daily and seasonal inactivity. To better understand why N. americanus is in decline, the importance of soil texture, moisture, vegetation, gravel, the burial depth, and the effect of compaction on their burying behavior was examined.

All tested species preferred moist soils with N. orbicollis having a significant preference for wet (pN. marginatus had a significant preference for …

Coupling Soil Oxygen And Greenhouse Gas Dynamics, Karla M. Jarecke

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

Dynamic soil hydrology triggers important shifts in soil biogeochemical and physical processes that control greenhouse gas (GHG) emissions. Soil oxygen (O₂), a direct control on biogenic GHG production (e.g. nitrous oxide-N₂O, carbon dioxide-CO₂ and methane-CH₄), may serve as both an important proxy for determining sudden shifts in subsurface biogenic GHG production as well as the physical transport of soil GHG to the atmosphere. Recent technological advancements offer opportunities to link in-situ, near-continuous measurements of soil O₂ concentration to soil biogeochemical processes and soil gas transport. Using high frequency data, this study …

Acute Toxicity Of Β-N-Methylamino-L-Alanine (Bmaa) To Fathead Minnow (Pimephales Promelas) And Zebrafish (Danio Rerio), Jiayi Wang

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

β-N-methylamino-L-alanine (BMAA) is a neurotoxic amino acid produced by most species of cyanobacteria. Exposure to BMAA has been hypothesized as a cause of ALS and possibly Parkinson’s and Alzheimer’s diseases for several decades. Both in vitro and in vivo experiments revealed that exposure to elevated concentrations of BMAA can damage motor neurons and cause motor dysfunctions. However, the exact mechanism of BMAA-induced neurotoxicity has not been well understood.

Based on the available literature and in spite of its water-soluble and non-protein nature, BMAA appears to be able to bioaccumulate in organisms. The ubiquity of cyanobacteria and the potential for bioaccumulation …

Genetic And Morphological Variation In Ecuadorian Astroblepid Catfishes, Katherine M. Lawry

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

The Andean ichthyofauna remains a poorly understood component of Neotropical biodiversity, and stands in stark contrast to the lowland ichthyofauna in terms of number of species and range of distribution. The Climate Variability Hypothesis (CVH) predicts rapid turnover of species along elevational gradients in tropical climates, but it remains unclear whether stream fishes follow this pattern. Astroblepid catfishes represent a distinctive assemblage of species that inhabit high elevation streams throughout the Andes from Panama to Bolivia, and constitute the only native fish family present in the Ecuadorian highland region. In this research, population samples of Astroblepids collected throughout Ecuador’s Napo …

The Status Of Fishes In The Missouri River, Nebraska: Blue Sucker Cycleptus Elongatus, Kirk D. Steffensen, Sam Stukel, Dane A. Shuman

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Blue Sucker Cycleptus elongatus are a large-bodied, benthic fish that are considered an indicator species for riverine health. A combination of historic commercial fishing and anthropogenic modifications to riverine habitat led to blue suckers being listed as a candidate species for the federal threatened or endangered species list in 1993. However, they were never designated a federally protected species. Locally, Blue Suckers are currently listed as a Nebraska Natural Legacy Project’s Tier 1 species but population changes and trends have not been quantified. Therefore, the objective of this paper was to evaluate the current population status of Blue Sucker in …

Phylogenetic And Fossil Evidence For A Common Body Size Attractor In Marine Mammals, William Gearty, Jonathan Payne

School of Biological Sciences: Posters and Presentations

Evolutionary transitions between terrestrial and aquatic habitats are rare and often have large effects on the evolutionary trajectory of the clade making the transition. Following a single transition from the marine realm to the terrestrial realm, tetrapods have subsequently re-evolved a marine lifestyle at least 30 separate times. At least six of these re-invasions of the water occurred within crown-group mammals and four [sirenians (Sirenia), whales (Cetacea), pinnipeds (Pinnipedia), and otters (Lutrinae)] clades are extant. Although marine mammals are widely known to be larger than their terrestrial sister groups, the extent to which the body size evolution of these clades …

Yellowstone Wolf (Canis Lupus) Density Predicted By Elk (Cervus Elaphus) Biomass, L. David Mech, Shannon M. Barber-Meyer

USGS Northern Prairie Wildlife Research Center

The Northern Range (NR) of Yellowstone National Park (YNP) hosts a higher prey biomass density in the form of elk (Cervus elaphus L., 1758) than any other system of gray wolves (Canis lupus L., 1758) and prey reported. Therefore, it is important to determine whether that wolf–prey system fits a long-standing model relating wolf density to prey biomass. Using data from 2005 to 2012 after elk population fluctuations dampened 10 years subsequent to wolf reintroduction, we found that NR prey biomass predicted wolf density. This finding and the trajectory of the regression extend the validity of the model …

Evaluation Of A Formula That Categorizes Female Gray Wolf Breeding Status By Nipple Size, Shannon M. Barber-Meyer, L. David Mech

USGS Northern Prairie Wildlife Research Center

The proportion by age class of wild Canis lupus (Gray Wolf) females that reproduce in any given year remains unclear; thus, we evaluated the applicability to our long-term (1972–2013) data set of the Mech et al. (1993) formula that categorizes female Gray Wolf breeding status by nipple size and time of year. We used the formula to classify Gray Wolves from 68 capture events into 4 categories (yearling, adult non-breeder, former breeder, current breeder). To address issues with small sample size and variance, we created an ambiguity index to allow some Gray Wolves to be classed into 2 categories. We …

Gray Wolf (Canis Lupus) Dyad Monthly Association Rates By Demographic Group, Shannon M. Barber-Meyer, L. David Mech

USGS Northern Prairie Wildlife Research Center

Preliminary data from GPS-collared wolves (Canis lupus) in the Superior National Forest of northeastern Minnesota indicated wolves had low association rates with packmates during summer. However, aerial-telemetry locations of very high frequency (VHF)-radioed wolves in this same area showed high associations among packmates during winter. We analyzed aerial-telemetry-location data from VHF-collared wolves in several packs (n=18 dyads) in this same area from 1994-2012 by month, and found lowest association rates occurred during June. While other studies have found low association among wolf packmates during summer, information on differences in association patterns depending on the wolf associates’ demographics is …

White-Tailed Deer (Odocoileus Virginianus) Fawn Risk From Gray Wolf (Canis Lupus) Predation During Summer, L. David Mech, Aaron Morris, Shannon M. Barber-Meyer

USGS Northern Prairie Wildlife Research Center

Little is known about how often various prey animals are at risk of predation by Gray Wolves (Canis lupus). We used a system to monitor the presence during the day of two radio-collared Gray Wolves within 2 km of a radio-collared White-tailed Deer (Odocoileus virginianus) with a fawn or fawns in August 2013 in the Superior National Forest of northeastern Minnesota. We concluded that the fawn or fawns were at risk of predation by at least one wolf at least daily.

2015 Academic Program Review School Of Natural Resources University Of Nebraska–Lincoln

School of Natural Resources: Documents and Reviews

No abstract provided.

Revisión Bibliográfica De Algunos Términos Ecológicos Usados En Parasitología, Y Su Aplicación En Estudios De Caso, Christian Elizbeth Bautista-Hernández, Scott Monks, Griselda Pulido-Flores, Amado Erick Rodríguez-Ibarra

Estudios en Biodiversidad

Se realizó una revisión bibliográfica de los términos ecológicos usados en parasitología, de acuerdo con Margolis et al. (1982), Esch et al. (1990), Bush et al. (1997), Bush et al. (2001) y Zander, (2001), que hasta 1982 era un conflicto en parasitología, ya que a que no existían conceptos establecidos para esta área del conocimiento, debido a que esta disciplina se enfocaba principalmente en investigaciones médicas. Aunado a esto, se incurría en conflictos con los conceptos ecológicos como hábitat, sitio, localidad entre otros de igual valor. Con base en lo anterior Margolis et al. (1982) propusieron el desarrollo de nuevos …

Riqueza De Helmintos Parásitos De Vertebrados Silvestres Del Estado De Hidalgo, México, Jorge Falcón-Ordaz, Scott Monks, Griselda Pulido-Flores, Luis García-Prieto, Georgina Lira-Guerrero

Estudios en Biodiversidad

La diversidad de helmintos parásitos de vertebrados del estado de Hidalgo, en México es poco conocida, a pesar de que su estudio se inició desde 1937. Asimismo, mucha de la información generada se ha publicado de manera dispersa, lo que dificulta aún más el establecer con precisión los valores actuales. Por ello, el objetivo de este trabajo fue determinar la riqueza de la fauna helmintológica asociada a vertebrados silvestres de Hidalgo. Para alcanzar dicho objetivo, se realizaron tres acciones: 1) recopilación bibliográfica retrospectiva de información; 2) consulta al acervo de diversas colecciones científicas nacionales e internacionales, e 3) incorporación de …

Nuevos Registros Y Redescripción De Rhabdochona Xiphophori Caspeta-Mandujano, Moravec Y Salgado- Maldonado, 2001 (Nematoda: Rhabdochonidae) En El Estado De Hidalgo, México, Jorge Falcón-Ordaz, Scott Monks, Griselda Pulido-Flores, Christian Elizbeth Bautista-Hernández, Sarahi Hernández-Hernández

Estudios en Biodiversidad

Teniendo en cuenta la diversidad de los ecosistemas acuáticos en México y la infinita riqueza de especies de peces en el país, la lista actual de nemátodos parásitos de peces de agua dulce en México está incompleta. Hasta la fecha en México el género Rhabdochona se encuentra registrado como parásito en una amplia gama de familias de peces de agua dulce. El objetivo del presente trabajo es redescribir ejemplares de Rhabdochona xiphophori parásita de Xiphophorus malinche colectados de dos localidades del estado de Hidalgo y compararlos morfológicamente.

Evaluación De Las Infracomunidades De Tres Especies De Peces En Dos Localidades De La Huasteca Hidalguense, Christian Elizbeth Bautista-Hernández, Scott Monks, Griselda Pulido-Flores

Estudios en Biodiversidad

Uno de los problemas más severos y menos controlados en México es el gran número de especies introducidas en las cuencas del país, hecho que pone en peligro la existencia de muchas de las especies endémicas. Además, las especies introducidas pueden transportar sus parásitos, que con frecuencia afectan a las poblaciones de especies endémicas. Anteriormente se realizó un estudio de las comunidades de parásitos de tres especies de peces, dos endémicas y una exótica (Xiphophorus birchmanni, Pseudoxiphophorus bimaculata y Amatitlania nigrofasciata). En ese trabajo se realizó el análisis de éstas comunidades evaluándolas a nivel infracomunidad, además se calculó la caracterización …

Helmintos Parásitos De Fauna Silvestre En Las Costas De Guerrero, Oaxaca Y Chiapas, México, Griselda Pulido-Flores, Scott Monks, Jorge Falcón-Ordaz, Juan Violante-González

Estudios en Biodiversidad

La costa sureste del Pacífico en México es rica en biodiversidad, en parte por la posición en la intersección de las corrientes oceánicas ecuatoriales. Sin embargo, los helmintos son un grupo de organismos que ha sido poco estudiado en la región y los registros están en diversas fuentes de información. El propósito de este trabajo es juntar todos los registros de las diferentes especies de hemintos en uno solo. Los registros publicados de helmintos parásitos de vertebrados de la zona incluyen 192 especies de Digenea, Monogenea, Cestoda, Acanthocephala, Nematoda e Hirudinea. Los Digenea son los mejor representados con 34 familias …