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Grazing Animal Production Systems And Grazing Land Characteristics In A Semi-Arid Region Of Greece, I. Hadjigeorgiou, G. Economou, D. Lolis, N. Moustakas, G. Zervas

IGC Proceedings (1977-2023)

Rough grazing in Greece cover about 40% of the total land area, is publicly owned and managed extensively (Hadjigeorgiou et al., 2002). The Prefecture of Larisa is in the centre of Greece, and has 212,000 ha of rough grazing land, with a variable topography ranging from sea level up to 3,000 m a.s.l. This area is utilized by a total population of 135,000 LU (mainly sheep, goats and some suckler cows), which consumes annually an appreciable fraction of their total nutrient requirements from rough grazing.

The Productivity Of Coastal Meadows In Finland, R. Nevalainen, S. Jaakola, A. Huuskonen, J. Kiljala, E. Joki-Tokola

IGC Proceedings (1977-2023)

The coastal meadows of Finland have gained a new interest as a summer pasture for cattle. These habitats have great historical, aesthetic and biological value (Pessa & Anttila, 2000). Typical features of the coastal meadows are the varying vegetation zones and wet, sometimes waterlogged, soils. The meadows are important nesting and feeding habitats for many water birds. When grazing ceases, reeds, trees and shrubs take over and the area loses its openness. Lately the amount of grasslands and pastures has drastically declined all over Europe. In Finland, the area of semi-natural biotopes has decreased to 1% of what it had …

Grass And Forage Plant Improvement In The Tropics And Sub-Tropics, Liana Jank, C. B. Do Valle, Rosangela M. S. Resende

IGC Proceedings (1977-2023)

1. The majority of tropical and subtropical forage grass genera and/or species have not yet been collected, or need further collection to be representative of their natural distribution.
2. New biotechnological techniques will only result in the release of superior forage cultivars if supported by strong breeding programs.
3. More funding and investment in the formation of strong public research teams in forage conservation and improvement are needed to guarantee the sustainability of tropical and subtropical pasture-based livestock systems in the future.
4. The creation of a permanent international working group on tropical and subtropical forages is essential to assist the International Plant Genetic …

Dinitrogen Emissions Dominate Nitrogen Gas Emissions From Soils With Low Oxygen Availability In A Moist Tropical Forest, Maya Almaraz, Peter M. Groffman, Whendee L. Silver, Steven J. Hall, Yang Lin, Christine S. O'Connell, Stephen Porder

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Lowland tropical forest soils are relatively N rich and are the largest global source of N₂O (a powerful greenhouse gas) to the atmosphere. Despite the importance of tropical N cycling, there have been few direct measurements of N₂ (an inert gas that can serve as an alternate fate for N₂O) in tropical soils, limiting our ability to characterize N budgets, manage soils to reduce N₂O production, or predict the future role that N limitation to primary productivity will play in buffering against climate change. We collected soils from across macro- and micro-topographic gradients …

Inter-Seasonal Comparison Of Acoustic Propagation In A Thalassia Testudinum Seagrass Meadow In A Shallow Sub-Tropical Lagoon, Kevin M. Lee, Megan S. Ballard, Andrew R. Mcneese, Preston S. Wilson, Gabriel R. Venegas, Mathew C. Zeh, Abdullah Rahman

School of Earth, Environmental, & Marine Sciences Faculty Publications

Acoustic propagation measurements were collected in a seagrass meadow in a shallow lagoon for periods of over 65 h in winter and 93 h in summer. A bottom-deployed sound source transmitted chirps (0.1–100 kHz) every 10 min that were received on a four-receiver horizontal hydrophone array. Oceanographic probes measured various environmental parameters. Daytime broadband acoustic attenuation was 2.4 dB greater in summer than winter, and the median received acoustic energy levels were 8.4 dB lower in summer compared to winter. These differences were attributed in part to seasonal changes in photosynthesis bubble production and above-ground seagrass biomass.

Balancing Renewable Energy And River Resources By Moving From Individual Assessments Of Hydropower Projects To Energy System Planning, Jeffrey J. Opperman, Juan Pablo Carvallo, Rafael Kelman, Rafael J. P. Schmitt, Rafael M. Almeida, Emily Chapin, Alexander Flecker, Marc Goichot, Guenther Guenther Grill, Julien J. Harou

School of Earth, Environmental, & Marine Sciences Faculty Publications

As governments and non-state actors strive to minimize global warming, a primary strategy is the decarbonization of power systems which will require a massive increase in renewable electricity generation. Leading energy agencies forecast a doubling of global hydropower capacity as part of that necessary expansion of renewables. While hydropower provides generally low-carbon generation and can integrate variable renewables, such as wind and solar, into electrical grids, hydropower dams are one of the primary reasons that only one-third of the world’s major rivers remain free-flowing. This loss of free-flowing rivers has contributed to dramatic declines of migratory fish and sediment delivery …

Inter-Seasonal Comparison Of Acoustic Propagation In A Thalassia Testudinum Seagrass Meadow In A Shallow Sub-Tropical Lagoon, Kevin M. Lee, Megan S. Ballard, Andrew R. Mcneese, Preston S. Wilson, Gabriel R. Venegas, Mathew C. Zeh, Abdullah Rahman

School of Earth, Environmental, & Marine Sciences Faculty Publications

Acoustic propagation measurements were collected in a seagrass meadow in a shallow lagoon for periods of over 65 h in winter and 93 h in summer. A bottom-deployed sound source transmitted chirps (0.1–100 kHz) every 10 min that were received on a four-receiver horizontal hydrophone array. Oceanographic probes measured various environmental parameters. Daytime broadband acoustic attenuation was 2.4 dB greater in summer than winter, and the median received acoustic energy levels were 8.4 dB lower in summer compared to winter. These differences were attributed in part to seasonal changes in photosynthesis bubble production and above-ground seagrass biomass.

Characterizing The Vegetation And Effects Of Climate Change On Parris Island, A Sea Island Ecosystem, Cody Hart Goodson

Theses, Dissertations and Capstones

Coastal habitats provide many ecosystem services, protecting coastlines from storm surges and erosion, diminishing the effects of eutrophication, sequestering large amounts of carbon, and acting as vital wildlife habitat. Sea-level rise and increased storm surge intensity associated with climate change are increasingly disrupting coastal habitats. These disturbances can shift environmental gradients that drive the zonation of coastal vegetation types, driving habitat conversion. Monitoring coastal habitat conversion can improve our understanding of the dynamic effects of climate change on these landscapes. Therefore, our objectives for chapter 1 were to identify and describe the distributions of vegetation types present on Marine Corps …

Globally Scalable Approach To Estimate Net Ecosystem Exchange Based On Remote Sensing, Meteorological Data, And Direct Measurements Of Eddy Covariance Sites, Ruslan Zhuravlev, Andrey Dara, André Luís Diniz Dos Santos, Oleg Demidov, George Burba

Daugherty Water for Food Global Institute: Faculty Publications

Despite a rapid development of Nature-Based Solutions (NBS) for carbon removal in recent years, the methods for evaluating NBS still have certain gaps. We propose an approach based on a combination of remote sensing data and meteorological variables to reconstruct the spatiotemporal variation of net ecosystem exchange from eddy-covariance stations. A Lagrangian particle dispersion model was used for upscaling satellite images and flux towers. We trained data-driven models based on kernel methods separately for each selected land-cover class. The results suggest that the proposed approach to quantifying carbon exchange on a medium-to-large scale by blending eddy covariance flux data with …

Effects Of Phosphorus-Binding Agents On Nutrient Dynamics And A Planktothrix Bloom In A Shallow, Semi-Enclosed Lake Area, Joseph Lee Davidson

Browse all Theses and Dissertations

Grand Lake St. Marys is the largest (52 km2) inland lake in Ohio, USA, and receives high nutrient loadings (90th percentile for total nitrogen (N) and phosphorus (P) concentrations in the USA) from a watershed dominated by agricultural row-crops and livestock production. Eutrophication has led to cyanobacterial harmful algal blooms, dominated by non-N2 fixing Planktothrix, that persist year-round, including in winter months. In summer 2020 and 2021, multiple treatments using P-binding agents within a 3.5 ha swimming enclosure were conducted to remove excess dissolved P from the water column. The objective of this study was to examine pre-and-post treatment biogeochemical …

Cover Crop Composition In Long-Term No-Till Soils In Semi-Arid Environments Do Not Influence Soil Health Measurements After One Year, Hunter Bielenberg, Jason D. Clark, Debankur Sanyal, Johnathon Wolthuizen, David Karki, Amin Rahhal, Anthony Bly

Agronomy, Horticulture and Plant Science Faculty Publications

Evaluating the influence of grass or broadleaf cover crops on soil health measurements is common in the northern US Midwest. However, the comparison among different cover crop mixtures, including blends of both grass and broadleaf species is limited. In 2018–2020, cover crop experiments were conducted in South Dakota at 11 site-years. Cover crops were planted in the summer after small grains harvest as mixtures of dominantly grasses or broadleaves, a 50/50 grass/broadleaf mixture, and a no cover crop control. Soil and above-ground plant residue samples were collected in the fall before winter termination and in the spring before corn planting. …

Rapid Growth In Late Cretaceous Sea Turtles Reveals Life History Strategies Similar To Extant Leatherbacks, Laura E. Wilson

Geosciences Faculty Publications

Modern sea turtle long bone osteohistology has been surprisingly well-studied, as it is used to understand sea turtle growth and the timing of life history events, thus informing conservation decisions. Previous histologic studies reveal two distinct bone growth patterns in extant sea turtle taxa, with Dermochelys (leatherbacks) growing faster than the cheloniids (all other living sea turtles). Dermochelys also has a unique life history compared to other sea turtles (large size, elevated metabolism, broad biogeographic distribution, etc.) that is likely linked to bone growth strategies. Despite the abundance of data on modern sea turtle bone growth, extinct sea turtle osteohistology …

A Study Of The Cultural And Geological Environment Of The Magic Mountain Site In Golden, Colorado, Brianna K. Dalessandro

Electronic Theses and Dissertations

The Magic Mountain site, located in Golden, Colorado, has been the subject of intensive academic studies since the 1950s because of its extensive artifact assemblage and long habitation periods. The aim of this thesis was to use ground-penetrating radar, magnetometry, GIS models, and lithic analysis to further study when and how the Magic Mountain site was used during prehistoric times and contextualize a variety of hypotheses about site habitation and migratory patterns of prehistoric people in Colorado.

The results of these analyses indicate the habitation and migratory pattern of the Magic Mountain site was a periodic, but consistent, proximal visitation …

Mineral-Specific Issues In 3d Scanning And Printing For Digital Collections, Outreach And Display, Selby Hearth, Bronwen Densmore

Geology Faculty Research and Scholarship

Three-dimensional (3D) scanning and 3D printing of natural history specimens presents interesting opportunities for informal and formal science education, as well as specimen preservation and display. Museum staff in several museums have begun scanning and making specimens available online. However, very few mineral specimens are available as scanned 3D objects, because minerals present unique challenges in scanning. Specifically, their variable surface reflection properties (“luster”) and surface complexities make them complicated specimens to reproduce. This paper examines the variables involved in 3D scanning and 3D printing mineral specimens, lays out criteria for ideal candidates, and presents workarounds to common problems. In …

Diagram Affordances And Their Impact On Students’ Answers About Rivers And Groundwater, Daniel R. Curtis

Graduate Research Theses & Dissertations

Diagrams are important tools for conveying information in geoscience education. Choosing what imagery to use and assessing its effectiveness is not straightforward. A diagram needs sufficient affordances (i.e., details, dimension) for the viewers to comprehend the intended message without adding too many details that will confuse and distract the viewer. Prior research suggests that the viewer’s knowledge and experience impact how diagram affordances are interpreted. Understanding this interaction between knowledge, context, and diagram affordance is critical for education and assessment.To investigate how changes in affordances affect student interpretation of images, we surveyed undergraduate students (N = 201) in introductory Earth …

Sheep Ingestive Behavior And Tannin Selection In Pampa Grassland And Feedlot, Marina Terra Braga

Green Canyon Environmental Research Area, Logan Utah

The Pampa grassland biome has high plant biodiversity, some with significant secondary compound concentrations such as tannins. Tannin inclusion in ruminant diets may improve meat quality and productivity. However, voluntary intake of this phenolic compound can be a challenge. This dissertation includes three studies within this context. The first study documented whether sheep consume tannin-rich Desmodium incanum (DI), the most common Pampa herbaceous legume species. The second study evaluated how forage tannin and protein concentration influenced sheep feedlot feed selection and the diet affects performance parameters. The third study evaluated sheep feeding behavior in a Pampa native pasture, and how …

The Use Of Transport Time Scales As Indicators Of Pollution Persistence In A Macro-Tidal Setting, Guanghai Gao, John J. O'Sullivan, Aisling Corkery, Zeinab Bedri, Gregory M.P. O'Hare, Wim G. Meijer

Articles

An understanding of water exchange processes is essential for assessing water quality management issues in coastal bays. This paper evaluates the impact of water exchange processes on pollution persistence in a macro-tidal semi-closed coastal bay through two transport time scales (TTS), namely residence time and exposure time. The numerical model was calibrated against field-measured data for various tidal conditions. Simulated current speeds and directions were shown to agree well with the field data. By considering different release scenarios of a conservative tracer by the refinement of an integrated hydrodynamic and solute transport model (the EFDC), the two TTS were used …

Academy Presidents And Institutional Members, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

The Geology Of El Paso, William Cornell, Diane Doser, Richard Langford, Joshua Villalobos, Jason Ricketts

Books & Monographs

The Geology of El Paso describes the history of El Paso, Texas and its surrounding region from the Precambrian formation of the continent to the modern use of geologic resources. This book is written in an easy to digest format, with definitions or links for specific geologic terms and references for further reading. It reviews the formation and evolution of local landmark features such as the Franklin Mountains, Cerro Cristo Rey, and the Sierra de Juarez. Fossils and stratigraphic units of the El Paso area are described as well as important geologic features. The book puts the events that shaped …

Helminth Parasites Of Northern Cottonmouth, Agkistrodon Piscivorus (Ophidia: Viperidae), From Arkansas, C.T. Mcallister, C.R. Bursey, H.W. Robison

Journal of the Arkansas Academy of Science

The Northern cottonmouth, Agkistrodon piscivorus is a large, semiaquatic viperid snake found statewide in Arkansas. Although a great deal has been published on helminth parasites of A. piscivorus from other parts of its range, little (outside of its cestodes) is known about those other helminths occurring in cottonmouths of the state. In our survey, we examined seven adult A. piscivorus from Polk County and a single specimen from Calhoun County. Several helminth parasites were found, including three trematodes, Styphlodora magna, Renifer ellipticus, and Paralechriorchis syntomentera, two nematodes, an unknown larval ascarid and Physaloptera abjecta, an oligacanthorhynchid acanthocephalan cystacanth, and a …

Investigating Changes In Permeability Caused By The Transport And Retention Of Microplastics In Saturated Sand Columns, Iliansherry Santiago

Graduate Research Theses & Dissertations

Microplastics (MPs), plastic particles present and continuously moving in our environment, represent a contaminant of global concern to the scientific community and society. MPs are particles less than 5 mm and are ubiquitous in our surroundings and the environment. MPs have been detected in oceans, soils, freshwater, drinking water and groundwater. MPs are considered contaminants of emerging concern (CEC), as they contain toxic components and serve as carriers for other contaminants that may affect the ecology and human health. Limited laboratory and field experiments demonstrate that MPs are transported and retained in porous media of a groundwater aquifer. A research …

Lithological Mapping Of Ophiolitic Rocks From Southern Part Of The Sivas Basin (Turkey) Using Aster Imagery, Taner Eki̇ci̇

Turkish Journal of Earth Sciences

The east-west extended Sivas Basin in central-eastern Anatolia is a foreland basin that formed after the obduction of the Tethyan ophiolite during the late Cretaceous and is also a north-verging fold-and-thrust belt. The basement rocks of the basin represent mainly sedimentary (Mesozoic platform-type carbonates) and late Cretaceous Divriği ophiolitic complex. As the ophiolitic rocks are affected by intense tectonic processes, field-based mapping studies require long processes and costs. The study tests to reveal the lithological features of the ophiolitic complex outcropping around the Ulaş district of the Sivas Province using remote sensing methods and techniques. Due to arid climatic conditions …

Determination Of Fatty Acid Concentrations In Various Strains Of Freshwater Green Picoplankton Algae (Class Eustigmatophyceae), P. Ashcraft, R. Jacks, B. Martinez, J. Rodriguez, A.B. Burns, A. Gurnsey, L. Taylor, A. Teague, J. Totty, V.L. Fox, A. Williams

Journal of the Arkansas Academy of Science

Algae are of scientific and commercial interest due to their ease of culture and high fatty acid content. The extracted fatty acids from these phytoplankton may potentially be used as an additional test for phylogenetic classification of new algal strains (Tonon et al. 2002), as well as in a supplement for human consumption and producing next-generation biofuels. Of interest is the fatty acid content contained within various algal isolates within the class Eustigmatophyceae. Algal strains were collected and isolated from locations in Lake Chicot in Arkansas, Tower Pond and Lake Itasca at Itasca State Park in Minnesota, and Thayer Lake …

Journal Of The Arkansas Academy Of Science Volume 77, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.

Determining Mating Type And Species Of A Natural Isolate Of Dictyostelium Using Molecular Techniques And Sexual Crosses, S.N. Baviskar, C. Catron, H. Jenkins, M. Smith

Journal of the Arkansas Academy of Science

Cellular slime molds, Dictyostelium, are bactivorous, soil-dwelling amoebae. When food is available, cells reproduce asexually by binary fission. Under certain environmental conditions, such as darkness and humidity, Dictyostelium reproduces sexually. The sexual cycle is uniquely social and has unusual features. First, sexual reproduction in most eukaryotes usually involves fusion of two gametes. But, in Dictyostelium, triparental inheritance is observed (Bloomfield et al. 2019), in which gamete fusion involves more than two gametes. Second, most eukaryotic species have two sexes or mating types, but Dictyostelium species are known to have more than two mating types. Even though Dictyostelium species show variations …

Noteworthy Parasites (Trematoda, Cestoda, Phthiraptera) Of Three Birds (Aves: Passeriformes; Pelecaniformes; Piciformes) From Arkansas, C.T. Mcallister, H.W. Robison

Journal of the Arkansas Academy of Science

Between November 2020 and March 2021, three species of birds, one each of a tufted titmouse (Baeolophus bicolor), pileated woodpecker (Dryocopus pileatus), and great blue heron (Ardea herodias) were salvaged from Lawrence and Polk counties, Arkansas, and examined for parasites. Found were four taxa of parasites, including a dicrocoeliid trematode, a cyclophyllidean cestode, and species of philopterid and menoponid lice. We document new host and distributional records for these parasites from select birds of the state.

Spermiogenesis In The Western Siren, Siren Nettingi (Caudata: Sirenidae), S.E. Trauth

Journal of the Arkansas Academy of Science

I investigated spermiogenesis in the Western Siren, Siren nettingi (formerly Western Lesser Siren, Siren intermedia nettingi) from salamanders collected periodically over a span of 21 yr (1994–2015) in northeastern Arkansas. My primary objective in this study is to present histologically and ultrastructurally, for the first time, the novel sequence of spermatological events of the spermiogenic process in this species. I describe the transformational stages from secondary spermatocytes to mature biflagellated spermatozoa, all of which occur within the lumen of testicular lobules. These new-to-science processes begin with nuclear displacement and expansion within spermatids, which occur after their detachment from Sertoli cells …

Histomorphology Of The Distal Urogenital Ducts In The Male Northern Crawfish Frog, Rana Areolata Circulosa (Anura: Ranidae), S.E. Trauth, R.G. Neal

Journal of the Arkansas Academy of Science

We examined the microanatomy of the distal urogenital ducts in the male Northern Crawfish Frog (Rana areolata circulosa) from a small sample (n = 5) collected in February and March from central Arkansas over a 5-year period (2017–2022). Specifically, we sought information on the following structures: (1) the paired Wolffian (urogenital) ducts caudally from the kidneys to their merging with the urodeum of the cloaca, (2) the paired seminal vesicles (sperm storage structures), and (3) the paired Müllerian ducts and glands. This study provides new information on these urogenital ducts and promotes a clearer understanding of this anatomical region for …

No Sperm Morphometric Differences Between Two Snapping Turtle Species, J.D. Konvalina, S.E. Trauth

Journal of the Arkansas Academy of Science

We examined sperm morphometrics between Chelydra serpentina and Macrochelys temminckii. When both species are combined, we found significant correlations between total sperm length and sperm head length as well as sperm tail length and sperm head length. In addition, we observed significant correlations between total sperm length and sperm tail length. T-tests revealed no significant differences in any of the sperm morphometrics between the two species. Both snapping turtle species had greater values for every sperm morphometric when compared to another freshwater turtle. The strong correlation between total sperm length and sperm tail length is concurrent with what has previously …

Keynote Address And Meeting Program, Academy Editors

Journal of the Arkansas Academy of Science

No abstract provided.