Digital Commons Network^™

The Mid‑Pleistocene Transition: A Delayed Response To An Increasing Positive Feedback?, Anne Willem Omta, Peter Thomas

Faculty Scholarship

Glacial–interglacial cycles constitute large natural variations in Earth’s climate. The Mid-Pleistocene Transition (MPT) marks a shift of the dominant periodicity of these climate cycles from ∼40 to ∼100 kyr. Recently, it has been suggested that this shift resulted from a gradual increase in the internal period (or equivalently, a decrease in the natural frequency) of the system. As a result, the system would then have locked to ever higher multiples of the external forcing period. We find that the internal period is sensitive to the strength of positive feedbacks in the climate system. Using a carbon cycle model in which …

Adoption Of Brachiaria Grasses In Mexico And Central America: A Successful Story, F. Holmann, Pedro Argel, C. E. Lascano

IGC Proceedings (1977-2023)

In Latin America and the Caribbean (LAC) there has been a major effort to develop new pastures technologies, to increase livestock productivity for the extensive systems prevailing in the tropical lowlands. This multi-national and inter-institutional effort was initiated through the International Network for the Evaluation of Tropical Pastures (RIEPT, by its name in Spanish), which operated from 1976 to 1996 under CIAT leadership. This network became a platform for institutions to train technicians, share forage material from existing gene banks, study the behaviour of new germplasm under different environments, and established the exchange of scientific information to extrapolate research results …

Improved Livelihoods From Grasslands; The Case Of Napier Grass In Smallholder Dairy Farms In Kenya, David Miano Mwangi, D. Romney, S. Staal, I. Baltenweck, S. Mwendia

IGC Proceedings (1977-2023)

In Kenya, smallholder farmers produce about 80% of the marketed milk. The farming systems vary from mixed farms with up to 10 ha of land and < 10 dairy cows (Gitau et al., 1994; Anon., 1985), to intensive smallholder dairy producers in the high human population central Kenya region with 0.9 to 2 ha of land and 3-4 dairy cows (Staal et al., 2001a). Milk production depends heavily on the cultivation of forages, with Pennisetum purpureum (Napier grass) by far the most important. An estimated 350,000 of the 600,000 smallholder farms in Kenya grow and utilize P. purpureum on their farms.

There are …

Role Of Information And Information Providers In Technology Transfer, D. Undersander

IGC Proceedings (1977-2023)

Technology transfer is an essential component of economic change in society. Developers of new technology often fail to realize that there is a science to technology transfer. This lack of appreciation for the skills involved in information dissemination and in activities necessary to affect a change of action in an audience often severely limits the rate and amount of technology transfer that occurs. Significant differences exist between doing a news release or writing a publication and causing audience acceptance of a new technology. The old standards of expecting adoption of a new technology simply because it “will profit farmers” or …

The Contribution Of Participatory Research: On-Farm Research, P. F. Fennessy, N. J. Daniels, S. A. Chadwick, P. A. Speck

IGC Proceedings (1977-2023)

Participatory research in agriculture may range from research and technology development (R&D), carried out on a research station with some involvement of farmers, through to genuine participatory research involving researchers and farmers working together. The latter involves the end-user in actually carrying out aspects of the research and/or in the development and evaluation of technology that is appropriate to commercial enterprises. Researchers often question the validity of the ‘findings of on-farm participatory research’ as they are more comfortable with the ‘controlled’ environment of the research station. However if research is to be applied appropriately on farms, it must go through …

Participatory Research For Smallholder Livestock Systems: Applying Common Sense To Complex Problems, P. M. Horne, Werner Stür

IGC Proceedings (1977-2023)

Key Points:

1. Participatory approaches to research (PAR) bring researchers closer to farmers, the intended users of research outputs.

2. Active, functional participation of farmers in the evaluation and development of new technologies requires researchers to make an important commitment: respecting the knowledge, skills and opinions of farmers while maintaining confidence in their own scientific knowledge.

3. Farmer experimentation is not usually suitable to provide quantitative biophysical data (this can be achieved more effectively in researcher controlled experiments), but to provide qualitative information and improve understanding. This type of information can be collected systematically to enable rigorous analysis.

4. While …

Soil Biology And The Emergence Of Adventive Grassland Ecosystems, T. R. Seastedt

IGC Proceedings (1977-2023)

The last few years have seen an explosion of information on the responses and feedbacks of soil biota to species and environmental changes. Soil biologists, plant ecologists, and biogeochemists have been searching for patterns, generality and predictability in these relationships. A few brave souls have had the courage to assemble comprehensive assessments of soil biology in our rapidly changing world. Several years ago, I reviewed Wardle’s (2002) book emphasising the links between above- and belowground components of ecosystems. That activity – as well as the present one – provided me with the opportunity to survey recent findings in soil biology. …

Computer-Based Forage Management Tools: Historical, Current, And Future Applications, David B. Hannaway, C. Daly, D. F. Chapman, B. B. Baker, A. S. Cooper

IGC Proceedings (1977-2023)

Forage management has been an important human activity since the beginning of civilization. By comparison, the personal computer has been available only in the immediate past. The software developed to deal with the complexity of climate, soil, plant, animal, and socioeconomic factors has seen huge changes in a few decades. Mainframe computers facilitated numerical calculations for exploring relationships among dozens of variables. Personal computers opened the door for more individual scientist creativity and routine communication. Web-based communication globalised the option for multidisciplinary teams to tackle problems. Forage-related computer applications abound, allowing farmers, ranchers, and others to more effectively manage the …

Paying For Our Keep: Grasslands Decision Support In More-Developed Countries, Andrew D. Moore

IGC Proceedings (1977-2023)

“Models in grassland science have come to stay, and so they must be made to pay for their keep. To do that, it will be necessary to improve their scientific sophistication and their management relevance...” (Seligman, 1993).

Decision support (DS) tools in grassland agriculture have also come to stay. This review will examine the ways and means by which DS tools are being made to pay for their keep, with a focus upon DS efforts from the last decade and on the lessons that arise for those who develop DS tools for grasslands. A survey of the present state of …

Decision Support For Grassland Systems In Developing Countries, P. K. Thornton

IGC Proceedings (1977-2023)

Key points

1. Information flows in complex systems are often themselves highly complex, and decision support approaches based on linear input-output processes may have only limited impact.

2. How decisions are made, and how they can be appropriately supported, is often incompletely understood, in part because of inadequate understanding of the objectives and attitudes of all the decision makers involved.

3. Much of the developing world faces daunting problems in the coming 30 years, and appropriate information could play a critical role in dealing with these.

4. System complexity, household variability, and institutional intricacies have to be embraced rather than …

College Of Natural Sciences Newsletter, September & October 2022, College Of Natural Sciences

College of Natural Sciences Newsletters and Reports

Volume 3, Issue 6

Page 1 Dean's Message
Page 2 Awards & Recognition
Page 3 Midwest Regional ACS Meeting
Page 4 North Central ASM Meeting
Page 5 Geography Department Travel
Page 6-7 Media Coverage of CNS
Page 7 REMAST Program at SDState receives national spotlight
Page 8 Celebrating the lives of those who touched the College
Page 9 Innovative Learning Spaces
Page 10 Open PRAIRIE Data
Page 11 2022 CNS Scholarship Brunch
Page 12-14 Fall 2022 Outreach Events

Time-Varying Rates Of Organic And Inorganic Mass Accumulation In Louisiana Marshes And Relation To Sea-Level Change, Sophie Vincent

LSU Master's Theses

Louisiana wetlands are complex systems that require a continuous input of organic and inorganic material to keep pace with relative sea-level rise (RSLR). Marshes, specifically, rely on organic material to build soil volume and maintain surface elevation. Interannual-to-decadal sea-level anomalies induced by Earth's internal climate variability and atmospheric disturbances such as hurricanes can affect marsh accretion, mineral deposition, and plant productivity. Coastal restoration projects such as sediment diversions are in progress to mitigate land loss and increase availability of inorganic sediment to coastal wetlands. The goal of this project is to determine if organic mass accumulation rates in Louisiana marshes …

Stability Of Fishes Assemblage Structure Over A Lustrum In Coastal Wetlands Under Different Disturbances In An Industrial Zone Of The Central Gulf Of Mexico Coast, Carlos E. Cintra-Buenrostro, Alejandro Fierro-Cabo

School of Earth, Environmental, & Marine Sciences Faculty Publications

Shallow coastal wetlands within the territory of an industrial port in southern Tamaulipas, Mexico, were monitored seasonally over a lustrum, focusing on their fishes assemblage and water parameters. The purpose was to characterize these ecosystems that are affected by different disturbances of industrial origin, document changes, and assess potentially degrading terms as the affectations prevailed over the period of study. The wetlands are differentially affected by impacting land uses in their immediate surroundings, by crude oil leaks, and/or by diverse industrial wastewater discharges. Water parameters varied only slightly over time for most sites, and relative disparities among sites remained. The …

A Rapid High-Precision Analytical Method For Triple Oxygen Isotope Analysis Of Co2 Gas Using Tunable Infrared Laser Direct Absorption Spectroscopy, Nathan Perdue, Zachary Sharp, David Nelson Jr., Rick Wehr, Christoph Dyroff

Earth and Planetary Sciences ETDs

Rationale

The simultaneous analysis of the three stable isotopes of oxygen – triple oxygen isotope analysis – has become an important analytical technique in natural sciences. Determination of the abundance of the rare ¹⁷O isotope in CO₂ gas using magnetic sector isotope ratio mass spectrometry is complicated by the isobaric interference of ¹⁷O by ­¹³C (¹³C¹⁶O¹⁶O and ¹²C¹⁶O¹⁷O both have mass 45 amu). A number of analytical techniques have been used to measure the ¹⁷O/¹⁶O ratio of CO₂ gas. They …

Concentration Of Heavy Metals In Three Distinct Algae Families From Humboldt County, California, Kodiak E. Miller, Caleb J. Strait, Jacob I. Begorre, Brittney L. Mitchell, Claire P. Till

IdeaFest: Interdisciplinary Journal of Creative Works and Research from Cal Poly Humboldt

Anthropogenic impacts on marine environments can impact metal fluxes and concentrations available to marine species. Monitoring these impacts is necessary to better understand the interactions between the biotic and abiotic components of these ecosystems and mitigate the risk posed by harmful toxins introduced by human activities. Biomoniters, like macroscopic algae, are useful indicators that illuminate the bioaccumulation of toxins commonly introduced from anthropogenic activity. With this in mind, the concentrations of heavy metals zinc (Zn), nickel (Ni), and copper (Cu) were analyzed via the assessment of algae (Representatives from Ulva, Mastocarpus, Fucus) in two sites in Humboldt County: …

Grazing Myths That Reduce Profitability, Greg Halich

Kentucky Grazing Conference

No abstract provided.

My Soil Is Alive! Introduction To Soil Life And Its Role In Profitable Grazing Systems, Ray Archuleta

Kentucky Grazing Conference

No abstract provided.

Beyond Functional Diversity: The Importance Of Trophic Position To Understanding Functional Processes In Community Evolution, Roxanne M. W. Banker, Ashley A. Dineen, Melanie G. Sorman, Carrie L. Tyler, Peter D. Roopnarine

Geoscience Faculty Research

Ecosystem structure—that is the species present, the functions they represent, and how those functions interact—is an important determinant of community stability. This in turn a􀀀ects how ecosystems respond to natural and anthropogenic crises, and whether species or the ecological functions that they represent are able to persist. Here we use fossil data from museum collections, literature, and the Paleobiology Database to reconstruct trophic networks of Tethyan paleocommunities fromthe Anisian and Carnian (Triassic), Bathonian (Jurassic), and Aptian (Cretaceous) stages, and compare these to a previously reconstructed trophic network from a modern Jamaican reef community. We generated model food webs consistent with …

Accelerate Construction Of New Pattern Of Ecological Protection In Northwest China, Qi Feng, Guangzu Bai, Zongxing Li, Bao Wang, Lijuan Chen, Penglong Wang, Tengfei Yu, Hongfei Meng, Wen Liu, Zhixiang Lu, Tingting Ning, Chengqi Zhang, Meng Zhu

Bulletin of Chinese Academy of Sciences (Chinese Version)

Based on a profound understanding of the great significance of constructing an ecological protection pattern in Northwest China, this paper systematically summarizes the achievements, new problems and new trends of ecological protection in Northwest China, and accordingly, puts forward an overall spatial arrangement for the ecological protection under "two regions (watersheds)-six zones (core ecological function zones)-multiple points (key ecological points)". In addition, a key path to construct a new pattern of ecological protection in Northwest China is expounded in order to make more contributions to the acceleration of the harmonious co-existence between human and nature. The path is mainly based …

Comparative Behavioral Ecotoxicology Of Inland Silverside Larvae Exposed To Pyrethroids Across A Salinity Gradient, Sara J. Hutton, Samreen Siddiqui, Emily I. Pedersen, Christopher Y. Markgraf, Amelie Segarra, Michelle L. Hladik, Richard E. Connon, Susanne M. Brander

United States Geological Survey: Staff Publications

Pyrethroids, a class of commonly used insecticides, are frequently detected in aquatic environments, including estuaries. The influence that salinity has on organism physiology and the partitioning of hydrophobic chemicals, such as pyrethroids, has driven interest in how toxicity changes in saltwater compared to freshwater. Early life exposures in fish to pyrethroids cause toxicity at environmentally relevant concentrations, which can alter behavior. Behavior is a highly sensitive endpoint that influences overall organism fitness and can be used to detect toxicity of environmentally relevant concentrations of aquatic pollutants. Inland Silversides (Menidia beryllina), a commonly used euryhaline model fish species, were exposed …

Coastal Wetland Area Change For Two Freshwater Diversions In The Mississippi River Delta, John R. White, Brady Couvillion, John W. Day

United States Geological Survey: Staff Publications

Coastal systems around the globe are being re-integrated with adjacent river systems to restore the natural hydrologic connection to riparian wetlands. The Mississippi River sediment diversions or river reconnections are one such tool to combat high rates of wetland loss in coastal Louisiana, USA by providing freshwater, sediment, and nutrients. There has been some disagreement in the published literature whether re-establishing river reconnection is slowing or contributing to coastal wetland loss. This issue is due to the difficulties in the application of remote sensing in low-relief environments where water level changes could indicate either land loss or simply temporary submergence. …

Perceptions Of Earth Science Using Assistive And Supportive Technologies By Students Who Are Blind Or Visually Impaired, Rhea G. Miles, Alana Zambone, Alex Manda

Journal of Science Education for Students with Disabilities

Students with blindness or visual impairments (BVI) need to participate in scientific laboratory experiences at the K12 level to be successful in college-level science courses. These K12 level students need instruction to actively conduct science experiments and not only allow sighted students to conduct them. While it may be a challenge, with appropriate assistive and supportive technologies, students with BVI can be successful in conducting scientific investigations to address Next Generation Science Standards. The Discoveries in Earth Science (DES) program provides engaging accommodations adaptive to the needs of elementary, middle, and high school grade students with BVI to successfully prepare …

Combined Effects Of Scarification, Phytohormones, Stratification, And Soil Type On The Germination And/Or Seedling Performance Of Three Tamaulipan Thornscrub Forest Species, Paula Luera, Christopher A. Gabler

School of Earth, Environmental, & Marine Sciences Faculty Publications

Tamaulipan thornforests in south Texas and northeast Mexico are a conservation hotspot. Shortages of native seedlings limit regional restoration and are largely driven by knowledge gaps regarding propagation of the 75+ thornforest species planted during restorations. We previously investigated three thornforest species with low or inconsistent germination or seedling survival: Ebenopsis ebano (Fabaceae), Cordia boissieri (Boraginaceae), and Zanthoxylum fagara (Rutaceae), and identified the types and dosages of chemical seed treatments that maximized germination. However, chemical treatments were performed in isolation and combinational treatments may be required to break dormancy or maximize germination. This study builds on prior work by investigating …

Observations On Late Cretaceous Micrampulla (Corethrales, Bacillariophyceae) From The Campbell Plateau (Zealandia), Southwest Pacific Ocean, Kenta Abe, David M. Harwood, Richard W. Jordan

Department of Earth and Atmospheric Sciences: Faculty Publications

Late Cretaceous (late Campanian) diatom assemblages from the Campbell Plateau (Zealandia), southwest Pacific Ocean, obtained from Deep Sea Drilling Project (DSDP) Leg 29 Site 275, contain well-preserved specimens of two enigmatic diatom species currently assigned to the genus Ktenodiscus; Micrampulla parvula originally described from the Maastrichtian-age Moreno Shale, California, and Pterotheca cretacea from DSDP Site 275. In general, the two species share a number of common features with modern Corethron (domed valves, probable heterovalvate frustules, T-shaped serrated articulated spines, marginal sockets), but differ in the location of the sockets (i.e. vertically at the base of the valve dome and …

Key Issues Generated From The Xi International Rangeland Congress 2021: Summary And Way Forward, D. L. Coppock, A. J. Ash, B. Irving

IGC Proceedings (1977-2023)

The important issues, knowledge gaps, and evolving research approaches for the global rangelands are summarised in this review of submissions to the Joint XXIV International Grasslands and XI International Rangelands Congress (IGC/IRC). In the big picture, it is concluded that stand-alone studies of livestock production are becoming rare compared to that of the past International Rangelands Congresses (IRC). Rather, added effort is now being directed at understanding the fuller context of social-ecological systems (SESs) on rangelands in a quest to improve the prospects for sustainable resource management as well as the enhancement of human welfare. Although climate change is upon …

Joint International Grassland And International Rangeland Congress Kenya 2021: Grasslands Summary, James L. Klotz, J. H. Bouton

IGC Proceedings (1977-2023)

This summary used as its main sources the plenary and keynote papers and talks in Sub-theme 2: Forage Production and Utilization and Sub-theme 3: Livestock Production Systems as well as a sampling of oral talks presented at the XXIV International Grassland Congress (IGC). This IGC was held virtually and jointly with the International Rangeland Congress and hosted in Nairobi, Kenya during 23-29 October 2021. The XXIV IGC was also the first to be held on the African continent in Congress' 94-year history. The summary is further focused on that information presented under the concept "cultivated grasslands" (e.g., a small number …

Level And Pattern Of Overstory Retention Shape The Abundance And Long-Term Dynamics Of Natural And Created Snags, Charles B. Halpern, Allison K. Rossman, Joan C. Hagar

United States Geological Survey: Staff Publications

Standing dead trees, or snags, serve myriad functions in natural forests, but are often scarce in forests managed for timber production. Variable retention (VR), the retention of live and dead trees through harvest, has been adopted globally as a less intensive form of regeneration harvest. In this study, we explore how two key elements of VR systems — level (amount) and spatial pattern of live-tree retention — affect the carryover and post-harvest dynamics of natural and artificially created snags. We present nearly two decades of data from the DEMO Study, a regional-scale experiment in VR harvests of Douglas-fir-dominated forests in …

Evaluating Our Reliance On Rare Earth Minerals And Platinum Group Metals Over The Period Of 2012 To 2021, Ryan Smith

Fall Showcase for Research and Creative Inquiry

Rare Earth Elements (REE’s) are minerals used in our everyday lives. They can be found in our household appliances, phones, computers, cars, as part of wind turbines and solar panels. The US relies on imports of these rare earths from several other countries (e.g. China, Estonia, Malaysia, and Japan) as we cannot mine a majority of the minerals (e.g. cerium, lanthanum, europium, etc) domestically. Since the year 2012, the US has imported approximately 3,000 metric tons of rare earths, and in recent years, this number significantly increased. As of 2021, the US now imports approximately 43,000 metric tons of rare …

Regenerative Agriculture Framework For Island Ecosystems Using São Miguel As A Case Study, Mya Hunter

Independent Study Project (ISP) Collection

Context: Regenerative agriculture is a farming approach that uses soil health as the entry point to contribute to multiple objectives, such as improved nutrient cycling and climate regulation. Farmers can apply different practices to reach these objectives. The objectives and practices, however, are not equally relevant or applicable for farming systems on island ecosystems and the local context.

Objectives: The main objective of this paper, therefore, is to find out how solutions towards regenerative agriculture can be identified and evaluated as such that they result in meaningful advice for farmers on island ecosystems in order to mitigate the …

Investigating Primary Succession Following The Retreat Of The Breiðamerkurjökull Glacier, Iceland, Ella Roelofs

Independent Study Project (ISP) Collection

The accelerating rates of glacier retreat around the world as a result of climate change make the study of primary succession in expanding forefields increasingly important. While this is a well studied topic in many parts of the world, little data exists specific to Iceland. This study investigated vegetation development along a chronosequence of eight time periods in the Breiðamerkurjökull outwash plain. Data was collected on percent vegetation cover, dominant species, the number of unique plant groups, and percent cover of five substrate types at 10 plots (0.55 x 0.55 m quadrats) per time period. Important findings include the fact …