Life Sciences Commons^™

Biodiversity And Global Change In Terrestrial Ecosystems, Timothy John Ohlert

Biology ETDs

Terrestrial ecosystems are critical to human and ecological processes but many gaps in our knowledge remain regarding how terrestrial plant communities assemble and respond to global change. I used field experiments distributed around the world, including long-term experiments from the Sevilleta National Wildlife Refuge (SNWR) in New Mexico and deserts of the southwestern U.S., to evaluate the consequences of drought and other abiotic stressors on plant communities. Dominant grasses were particularly important for the productivity and structure of grasslands at SNWR. In general, the structure of desert plant communities had high resistance to extreme drought, though grasses and other perennial …

Climate Sensitive Diameter Growth Models For Major Tree Species In Mississippi, Sujan Subedi

Theses and Dissertations

Anticipated climate change and increasing wood demand require dependable diameter growth models for adaptive forest management. We used a mixed-effects modeling approach with Forest Inventory and Analysis (FIA) data to fit diameter growth models for loblolly pine, other softwood species (slash pine, shortleaf pine, and longleaf pine), sweetgum, and other hardwood (southern red oak, red maple, and water oak) species. Climatic variables coupled with individual tree attributes and competition factors improved climate insensitive models. Growth of loblolly pine and sweetgum was positively correlated with mean temperature of the coldest month. Mean temperature of the warmest month negatively influenced diameter growth …

Assessing Red Spruce (Picea Rubens) Restoration Potential Under Current And Future Predicted Climate Change In Virginia, Christian Brown

Masters Theses, 2020-current

Global climate change threatens many species across the planet. High-elevation species, such as red spruce (Picea rubens), face significant and immediate threats from climate change. Red spruce has faced anthropogenic disturbances for over a century and is only recently beginning to regenerate across its range, making it an ideal restoration candidate. Ecological niche modeling has become a common method of identifying the suitable habitat of a species, providing vital information to land managers carrying out restoration efforts. In this study ecological niche models were used in a novel way, predicting distribution and habitat suitability separately to determine the …

The Impacts Of Increased Precipitation Intensity On Dryland Ecosystems In The Western United States, Martin C. Holdrege

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As the atmosphere warms, precipitation events become larger, but less frequent. Such increases in precipitation intensity are expected regardless of changes in total annual precipitation. Despite strong evidence for increases in precipitation intensity, disagreement exists regarding how these changes will impact plants, and studies are lacking in many types of ecosystems. This dissertation addresses how increased precipitation intensity affects soil water availability, and how plants respond to any such changes. I address this question in the context of big sagebrush ecosystems and dryland winter wheat agriculture, which are both environments that can be sensitive to changes in water availability. Results …

Comparison Of Carbon Footprints Of School Lunches In Dangriga, Belize, And Northwest Arkansas, Lauren Greenwood

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

The original purpose of this study was to investigate differences in carbon footprints of school lunches by comparing a school in Arkansas, USA, and a school in Belize. Due to complications imposed by the COVID-19 pandemic, the purpose was revised to gathering preliminary data about the school lunch program at a school in Northwest Arkansas; data were to be used to estimate CO2-equivalent emissions for cafeteria energy use, meal ingredients from the two most popular meals served, and food transportation at the last point in the supply chain (food service delivery to school). This study highlights the intersection of food …

Seasonal Trends In Adult Apparent Survival And Reproductive Trade-Offs Reveal Potential Constraints To Earlier Nesting In A Migratory Bird, Kathleen R. Callery, John A. Smallwood, Anjolene R. Hunt, Emilie R. Snyder, Julie A. Heath

Biology Faculty Publications and Presentations

Birds aim to optimize resources for feeding young and self-maintenance by timing reproduction to coincide with peak food availability. When reproduction is mistimed, birds could incur costs that affect their survival. We studied whether nesting phenology correlated with the apparent survival of American kestrels (Falco sparverius) from two distinct populations and examined trends in clutch-initiation dates. We estimated apparent survival using multi-state mark-recapture models with nesting timing, nesting success, sex, age, and weather covariates. Nesting timing predicted the apparent survival of successful adults; however, the effect differed between populations. Early nesting kestrels had higher apparent survival than later …

Seasonal Trends In Adult Apparent Survival And Reproductive Trade-Offs Reveal Potential Constraints To Earlier Nesting In A Migratory Bird, Kathleen R. Callery, John A. Smallwood, Anjolene R. Hunt, Emilie R. Snyder, Julie A. Heath

Department of Biology Faculty Scholarship and Creative Works

Birds aim to optimize resources for feeding young and self-maintenance by timing reproduction to coincide with peak food availability. When reproduction is mistimed, birds could incur costs that affect their survival. We studied whether nesting phenology correlated with the apparent survival of American kestrels (Falco sparverius) from two distinct populations and examined trends in clutch-initiation dates. We estimated apparent survival using multi-state mark-recapture models with nesting timing, nesting success, sex, age, and weather covariates. Nesting timing predicted the apparent survival of successful adults; however, the effect differed between populations. Early nesting kestrels had higher apparent survival than later nesters in …

Sex, Body Size, And Winter Weather Explain Migration Strategies In A Partial Migrant Population Of American Kestrels (Falco Sparverius), Sadie Claire Ranck

Boise State University Theses and Dissertations

Partially migratory systems describe populations that consist of both individuals that migrate away from the breeding grounds for the winter, and others that remain resident near their nesting sites year-round. Partial migration is the most common type of migration across all animal taxa, but the evolution, maintenance, and consequences associated with different movement strategies are still poorly understood. Studying the factors that drive migratory strategies and the associated consequences of those decisions is important to understand how migratory animals may adapt to climate change. Partial migrant populations offer a great opportunity for which to study these questions because individuals with …

Describing The Effect Of Thin Layer Sediment Placement On Coastal Microbial Communities Using Foraminifera Diversity, Elizabeth B. Billings

Senior Honors Projects

Salt marshes are rich ecosystems that play an important role in aquatic food systems and prevent erosion while also providing essential habitats for wildlife. Climate change has resulted in rising sea levels and erosion of these coastal wetlands. Thin Layer Sediment Placement (TLP) is a restoration effort being implemented to mitigate the effects of climate change on coastal ecosystems. The TLP process raises elevation of the marsh and provides substrates for vegetative growth by spraying dredged sediment over existing marsh. The impacts of TLP on microbial populations is not widely understood, therefore metrics are required to study the effects of …

The Potential Impact Of Climate Change On The Distributions Of Eleutherodactylus Cystignathoides And E. Planirostris (Anura: Eleutherodactylidae), Rebecca T. Chastain

Theses and Dissertations

Climate change is inducing changes in the distributions of many species, causing range shifts and habitat loss as well as facilitating invasions. It is a broad contributor to global amphibian decline, already causing mass extinctions and extirpations of amphibian populations, a phenomenon which is expected to continue. The understudied direct-developing frog Eleutherodactylus cystignathoides is a notable outlier, having rapidly expanded its distribution in recent years. This is of particular interest given that other eleutherodactylids, such as E. coqui and E. planirostris, have already shown propensity for rapid dispersal and invasion. Originally found in the southernmost tip of …

Epidemiology And Impacts Of A Leaf Spot Disease In Veratrum Viride (Melanthiaceae), Leeah R. Sutton, Foster Levy

Undergraduate Honors Theses

Fungal phytopathogens can cause disease epidemics in crops, weeds, and
populations of native plants. To investigate the impact of a foliar phytopathogen on the native herbaceous species, Veratrum viride, a demographic and disease assessment was carried out on two high elevation grassy bald populations on Roan Mountain, Tennessee. A leaf spot disease impacted all plants in both populations, causing widespread premature senescence of leaves and stems. Disease severity increased over the course of the growing season. Based on host disease symptoms and fungal conidia morphology, Pseudocercosporella sublineolata was shown to be the causal pathogen. A study of herbarium specimens …

Climate Change And Management Impacts On Soybean N Fixation, Soil N Mineralization, N2O Emissions, And Seed Yield, Elvis F. Elli, Ignacio A. Ciampitti, Michael J. Castellano, Larry C. Purcell, Seth Naeve, Patricio Grassini, Nicolas C. La Menza, Luiz Moro Rosso, André F. De Borja Reis, Péter Kovács, Sotirios V. Archontoulis

Department of Agronomy and Horticulture: Faculty Publications

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N …

The Effects Of Increasing Ocean Temperatures On The Survivorship Of A Subtropical Population Of The Sea Urchin Arbacia Punctulata, Rhianna Clemons

Undergraduate Theses

Most sea urchin species have critical ecological roles in their ecosystems, such as keystone grazers. There is an increasing need to understand the impacts of rising temperatures on species that are vital to the health of their environments. Studies have shown that increasing temperatures may significantly negatively affect several important biological processes including reproduction, development, and excretion in many species including sea urchins. However, very little is known about the sea urchin species Arbacia punctulata. In this study, individuals were exposed to 21˚C (control, n = 12) and 27˚C (experimental, n = 12) for seven days, and survivorship was …

Canopy Arthropod Responses To Catastrophic Wind Disturbances In Gulf Coast And Caribbean Forests, Manoj Pandey

LSU Doctoral Dissertations

Hurricanes are major natural disturbances and integral components of forest disturbance regimes globally. The frequency and intensity of hurricanes are predicted to increase in the future due to global warming. The altered hurricane regime, along with direct effects of climate change on arthropod populations and communities, has the capacity to endanger the critical ecosystem processes and services provided by forest canopies. Therefore, it is crucial to understand the responses of forest fauna to disturbances such as hurricanes. This dissertation is aimed at understanding the short-term and long-term effects of hurricanes on canopy arthropods to improve predictions of the consequences of …

Physiological And Biochemical Thermal Stress Conditions Of The Ribbed Mussel, Geukensia Demissa, From Exposed And Less Exposed Areas In The Intertidal Salt Marsh On Tybee Island, Georgia., Jody E. Erber

Honors College Theses

Geukensia demissa, the ribbed mussel, is a keystone species of Georgia’s coastline that is at risk of experiencing detrimental thermal stress due to climate change. G. demissa interacts positively with a species of salt marsh cordgrass, Spartina alterniflora. Mussels form aggregates beneath salt marsh cordgrass stems where they are shaded and less exposed to sun rays. However, some mussels end up in areas which lack cordgrass and are directly exposed to sun rays. Body temperatures of mussels from exposed areas were found to be higher than mussels from less exposed areas. Thermal stress levels of mussels can be …

Los Impactos Del Cambio Climático En Las Comunidades Aymaras En Putre, El Valle De Azapa Y Arica, Lindsey Kaufman

Independent Study Project (ISP) Collection

Research Question: How is climate change affecting Aymara communities in Putre, the valley of Azapa, and Putre?

Objectives: To understand the effects of climate on communities by 1) describing which environmental problems exist and their impact on agriculture and ranching, 2) understanding the patterns of migration away from the ancestral land, 3) exploring the connections to the social determinants of health that exist with these change, and 4) analyzing the significance of these changes in the agriculture for the communities’ traditions and connection to the land.

Background: Aymara communities have historically inhabited agricultural and ranching lands in …

Seagrasses Under Times Of Change - Editorial, Gidon Winters, Mirta Teichberg, Hauke Reuter, Inés G. Viana, Demian A. Willette

Biology Faculty Works

No abstract provided.

The Risk Of Multiple Anthropogenic And Climate Change Threats Must Be Considered For Continental Scale Conservation And Management Of Seagrass Habitat, Kathryn Mcmahon, Kieryn Kilminster, Robert Canto, Chris Roelfsema, Mitchell Lyons, Gary A. Kendrick, Michelle Waycott, James Udy

Research outputs 2022 to 2026

Globally marine-terrestrial interfaces are highly impacted due to a range of human pressures. Seagrass habitats exist in the shallow marine waters of this interface, have significant values and are impacted by a range of pressures. Cumulative risk analysis is widely used to identify risk from multiple threats and assist in prioritizing management actions. This study conducted a cumulative risk analysis of seagrass habitat associated with the Australian continent to support management actions. We developed a spatially explicit risk model based on a database of threats to coastal aquatic habitat in Australia, spanning 35,000 km of coastline. Risk hotspots were identified …

Oyster Reef-To-Mangrove Regime Shifts Along The West Coast Of Florida, Stephen Gregory Hesterberg

USF Tampa Graduate Theses and Dissertations

Ecological regime shifts are transitions in ecosystem state, which can occur either when external conditions gradually change or when large perturbations force a system into an alternative state. Such transitions can exhibit non-linear dynamics, where small changes in external conditions can result in abrupt transition and often occur with little warning. After crossing a tipping point, the system may be unable to revert to its original state if the new regime possesses strong, reinforcing feedbacks. Numerous marine ecosystems have experienced regime shifts due to a combination of stressors that have eroded ecological resilience, such as overfishing, nutrient loading, and climate …

Methane And Nitrous Oxide Emissions From Grazed Grasslands, Harry Clark, C. Pinares-Patiño, C. De Klein

IGC Proceedings (1977-2023)

Key points

1. Emissions of methane (CH₄) and nitrous oxide (N₂O) from grasslands make a substantial contribution to total agricultural emissions of these two gases.

2. At present practical mitigation options that relate to grazing ruminants and grazed pastures are limited.

3. Research into agricultural greenhouse gas emissions is of low priority in most developed countries.

4. Direct manipulation of the rumen ecosystem provides the best opportunity for large reductions in CH₄ in the long term.

5. Reducing the amount of nitrogen (N) excreted by grazing animals is a priority in N₂O research, …

Climate Effects On Black Spruce And Trembling Aspen Productivity In Natural Origin Mixed Stands, Mahadev Sharma

Aspen Bibliography

Forest managers need site productivity estimates for tree species growing in mixed stands. Models developed in the past are generally for pure stands and don’t factor in the effects of climate change on site productivity. Therefore, site index (SI) models were developed for black spruce (Picea mariana Mill. B.S.P.) and trembling aspen (Populus tremuloides Michx.) trees grown in natural origin mixed stands. For this, 186 trees (93 black spruce and trembling aspen each) were sampled from 31 even-aged natural mixed stands (sites) (3 trees/species/site) across Ontario, Canada. Stand height growth models were developed by incorporating climate variables during …

Global Atmospheric Change And Its Effect On Managed Grassland Systems, Andreas Lüscher, J. Fuhrer, P. C. D. Newton

IGC Proceedings (1977-2023)

Key points

1. Increasing atmospheric CO2 concentration and a trend to warmer mean temperatures are the most reliable aspects of global atmospheric change. Projections of the extent of climate change and the frequency of extreme weather conditions remain uncertain.

2. Research has considerably reduced the uncertainty about effects of global atmospheric change on physiology of plants, productivity and species composition of plant communities.

3. Other factors (e.g. nutrient availability, soil type) and long-term adaptation of the ecosystem (e.g. nutrient cycling and sequestration) influence the response of plant communities to global atmospheric change. Generalisation is not possible with respect to the …

Wind And Fire: Rapid Shifts In Tree Community Composition Following Multiple Disturbances In The Southern Boreal Forest, Elias Anoszko, Lee E. Frelich, Roy L. Rich, Peter B. Reich

Aspen Bibliography

Under a warming climate, the southern boreal forest of North America is expected to see a doubling in fire frequency and potential for increased wind disturbance over the next century. Although boreal forests are often considered fire-adapted, projected increases in disturbance frequency will likely result in novel combinations of disturbances with severities and impacts on community composition outside historic norms. Using a network of repeatedly measured vegetation monitoring plots, we followed changes in tree community composition in areas of the Boundary Waters Canoe Area Wilderness (BWCAW), in Minnesota, USA, experiencing disturbances ranging from severe windstorms or wildfires to areas affected …

The Potential Of Grassland And Associated Forages To Produce Fibre, Biomass, Energy Or Other Feedstocks For Non-Food And Other Sectors: New Uses For A Global Resource, M. F. Askew

IGC Proceedings (1977-2023)

Key points

1. In developed countries increased areas of land will become available for non-food production. Recent reforms of the Common Agricultural Policy will further intensify this trend in Europe.

2. There is potential for grassland and associated species to contribute to large tonnage markets of energy and bulk fibres, to the supply of fermentation products and to speciality markets, but processes and approaches to the market are not as yet developed.

3. There is potential for the establishment of Graminaceous species - specifically for nonfood use. For European conditions particular attention is being given to Miscanthus sinensis (Miscanthus), Arundo …

Current Water Quality Guidelines Across North America And Europe Do Not Protect Lakes From Salinization, Matthew Schuler

Department of Biology Faculty Scholarship and Creative Works

Human-induced salinization caused by the use of road deicing salts, agricultural practices, mining operations, and climate change is a major threat to the biodiversity and functioning of freshwater ecosystems. Yet, it is unclear if freshwater ecosystems are protected from salinization by current water quality guidelines. Leveraging an experimental network of land-based and in-lake mesocosms across North America and Europe, we tested how salinization—indicated as elevated chloride (Cl²) concentration—will affect lake food webs and if two of the lowest Cl² thresholds found globally are sufficient to protect these food webs. Our results indicated that salinization will cause substantial …

Importance Of Local Weather And Environmental Gradients On Demography Of A Broadly Distributed Temperate Frog, Hallie Lingo, James C. Munger

Biology Faculty Publications and Presentations

Amphibian populations are sensitive to environmental temperatures and moisture, which vary with local weather conditions and may reach new norms and extremes as contemporary climate change progresses. Using long-term (11–16 years) mark-recapture data from 10 populations of the Columbia spotted frog (Rana luteiventris) from across its U.S. range, we addressed hypotheses about how demographic relationships to weather depend upon a population’s position along climate gradients. We estimated the effect of seasonal weather on annual survival probability and recruitment rates both within populations and across the species’ range from subalpine forests to semi-arid deserts. We calculated population-specific weather variables …

Ecopsychologists' Vital Importance In The Time Of Climate Crises, Nicole B. Auckerman Psyd

Antioch University Dissertations & Theses

Ecopsychology is a systems-based philosophy that expands the therapeutic lens to include client interactions with and perceptions of the natural environment as an integral element of well-being or pathology. Ecopsychology, known forward as EP, also looks at the pathology of our culture and what kind of diagnoses lead to practices that put our planet at risk. In recent decades, the field has amassed a substantial amount of empirical evidence supporting its effectiveness but remains largely underutilized. First generation EP suggested a cultural reordering shifting away from consumer culture and reordering our way of life. Second generation posits working within the …

Estimation Of The Optimal Nitrogen Dose In A Brachiaria Humidicola-Corn Rotation System In The Colombian Eastern Plains, K. Enciso, S. Burkart

IGC Proceedings (1977-2023)

Improving nitrogen (N) use efficiency by optimizing the N fertilizer application dose is one way to reduce greenhouse gas (GHG) emissions in agriculture and livestock production, especially in higher demanding crops such as corn. Taking a Brachiaria humidicola (Bh)-corn rotation system in the Colombian Eastern Plains, we seek to determine both the optimal economic dose (OED) and the optimal technical dose (OTD) of N, which allow to maximize income at producer level and minimize environmental impacts. This particular rotation system was chosen as research subject given the presence of the residual effect of Biological Nitrogen Inhibition (BNI) in …

The First Report Of Lissomus Dalman (Coleoptera: Elateridae: Lissominae) From The Greater Antilles, With Two New Species From The Dominican Republic, Paul J. Johnson

Insecta Mundi

Lissomus quisqueya new species and L. woodruffi new species are described. Both species are reported from the Dominican Republic on the island of Hispaniola. These are the first species of Lissomus Dalman reported from the Greater Antilles. Lissomus quisqueya is recorded from montane mesic forests in the Cordillera Central from Dajadon and La Vega provinces. Lissomus woodruffi is recorded from Barahona, Independencia and Pedernales provinces from montane mesic forest in the Sierra de Bahoruco. Morphologically, these species are most similar to members of the L. discedens Bonvouloir species group from Mesoamerica and South America. Known sites of occurrence of L. …

Innovative Approaches To Analysing Carbon Sequestration As A Mitigation Strategy In Tropical Pasture Landscapes In Two Emblematic Contexts, The Amazon And The West African Sahel, V. Blanfort, R. Pocard-Chapuis, J. Vayssières, M. Vignes, M. H. Assouma, B. Hubert, A. Ickowicz, S. Fontaine

IGC Proceedings (1977-2023)

The relationship between ruminant production systems and climate change is complex. As a major contributor to greenhouse gas (GHG) emissions, the sector has been the subject of considerable controversy, with particularly severe criticism in the 2000s. However, ten years ago, the attitude towards grazing lands began to change. Their efficient use of non-renewable energy and their contribution to carbon (C) sequestration were considered as key factors in the new environmental challenge. The reality of this mitigation potential was recently called into question once again in the global agriculture and climate change debate, including that of sequestration in the soil where …