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Full-Text Articles in Life Sciences
The Influence Of Traits On Species Responses To Climate Change: Does Warming Negatively Impact Native Species More Than Invasive Species?, Margaret Anne Mamantov
The Influence Of Traits On Species Responses To Climate Change: Does Warming Negatively Impact Native Species More Than Invasive Species?, Margaret Anne Mamantov
Doctoral Dissertations
Current climate change is increasing global temperatures so that many organisms are now experiencing temperatures outside of their thermal tolerance, which threatens their survival. Organisms respond to physiologically stressful temperatures to reduce this threat. Organisms respond to warming through three main mechanisms: range shifts, adjustments via phenotypic plasticity, and evolutionary adaptation. Organisms vary in their ability to utilize these three mechanisms, leading to differences in the magnitude and success of their adjustments to temperature change. Here, I examine how organismal traits influence variation in species response to climate change. Chapter one addresses how physiological tolerance may influence the rate of …
Evaluating Current And Future Potential Distribution Of Epiphytic Orchids In The Congo Basin With Ecological Niche Models, Michael L. Ngoh
Evaluating Current And Future Potential Distribution Of Epiphytic Orchids In The Congo Basin With Ecological Niche Models, Michael L. Ngoh
Masters Theses
The Congo Basin Forest harbors a rich diversity of epiphytic communities, with the Orchidaceae alone making up more than 50% of all epiphytes in the region. Despite the huge diversity of epiphytes, many species, including epiphytic orchids, are at risk to a diverse array of threats. Climate change for instance poses severe threats to epiphytic orchids due to elevated temperatures, prolonged periods of droughts, as well as reduced rainfall across the Congo Basin Forest. In this study, we used ecological niche modeling and GIS techniques to identify spatial patterns of species richness, potential future climate refugia, and novel climatic suitability …
Geographic Patterns Of Genetic Diversity Under Climate Change: Linking Genes And Ecosystems, Shannon L. Bayliss
Geographic Patterns Of Genetic Diversity Under Climate Change: Linking Genes And Ecosystems, Shannon L. Bayliss
Doctoral Dissertations
Climate change is having profound effects on species distributions. However, much less is understood about how climate change may alter the distribution of genetic variation within species across landscapes. Maintaining genetic diversity within populations is essential for the survival of species in the face of rapid climatic changes, but importantly, losses of genetic variation will also have significant consequences on entire ecosystems. The objective of this dissertation is to understand how genetic variation in a riparian cottonwood species, Populus angustifolia, affects mass and energy exchange between the land and atmosphere across ~1700 km of latitude of the western United …
Risk Management Potential Of Supplemental Irrigation For Cotton In A Sub-Humid Climate Under Climate Change, Wen Liu
Masters Theses
Adoption of supplemental irrigation to reduce cotton yield losses is a potential risk management strategy for farmers given increasingly frequent drought periods due to climate change. However, cotton farmers in the rolling landscape areas of the lower Mississippi River Basin (MRB) are concerned about whether an investment in supplemental irrigation is economically feasible. This study determined the impacts of the effects of risk exposure on optimal irrigation strategies for cotton production under climate change in West Tennessee. A crop simulation model was calibrated and validated using measured data from cotton irrigation experiments at Jackson, TN over three years (2006–2008). Simulated …
Evolution And Resurrection Ecology Of A Foundational Coastal Marsh Plant, Jennifer L. Summers
Evolution And Resurrection Ecology Of A Foundational Coastal Marsh Plant, Jennifer L. Summers
Doctoral Dissertations
Stratified storage of dormant seeds in soil can result in natural archives useful for studying evolutionary responses to environmental change. However, few studies leverage soil-stored seed banks as natural archives, in part because of concerns over attrition, bias, and sediment mixing. Here, I examine the persistent seed bank of Schoenoplectus americanus, a foundational brackish marsh sedge, to a) determine whether it can serve as a resource for reconstructing demographic and population genetic/genomic variation, b) whether and how evolution may be occurring across a century. After extracting seeds from radionuclide-dated soil cores taken across the Chesapeake Bay, I “resurrected” age …
Within-Reach Temperature Heterogeneity Is Limited In A Southern Appalachian Stream Network: Implications For Climate Change Refugia And Reach-Scale Temperature Mapping, Anna Kaz, Matthew Troia Dr., Xingli Giam Dr.
Within-Reach Temperature Heterogeneity Is Limited In A Southern Appalachian Stream Network: Implications For Climate Change Refugia And Reach-Scale Temperature Mapping, Anna Kaz, Matthew Troia Dr., Xingli Giam Dr.
Chancellor’s Honors Program Projects
No abstract provided.
Plasticity And Biotic Interactions Mediate Plant Persistence In A Changing World, Alix Ann Pfennigwerth
Plasticity And Biotic Interactions Mediate Plant Persistence In A Changing World, Alix Ann Pfennigwerth
Masters Theses
Anthropogenic global change is occurring today at a faster rate and larger scale than ever before. Understanding how plants will respond to such large-scale disturbance is critical for biodiversity conservation, yet the ecological and evolutionary mechanisms underlying these responses remain poorly understood. In this thesis, I investigated the mechanisms underlying plant response to two major drivers of global change, climate change and the widespread mortality of foundation species. First, I examined genetic and plastic plant trait responses to climatic variation using elevation gradients, which serve as space-for-time substitutions for climate change. Through field observations in three populations of the North …
Exploring Enrichment Cultures Of Denitrifying Microorganisms From El Yunque National Forest, Samiha Ahsan, Jenny Onley, Frank Loeffler
Exploring Enrichment Cultures Of Denitrifying Microorganisms From El Yunque National Forest, Samiha Ahsan, Jenny Onley, Frank Loeffler
Chancellor’s Honors Program Projects
No abstract provided.
Wood Decomposition In A Warmer World, Emily Elizabeth Austin
Wood Decomposition In A Warmer World, Emily Elizabeth Austin
Doctoral Dissertations
Climatic warming is altering species distributions and ecosystem functions across the globe. Wood is an important carbon pool and the fungal communities in wood are relatively simple compared to those in soil. These factors make decomposing wood an ideal system for exploring the influence of decomposer community on the response of decomposition to warming. My research has focused on the effects of warming wood decomposition rates and wood decomposing communities. Using field and lab- based manipulative experiments and field observations I explore the influence of tree species, wood decomposition stage, geography and warming on fungal community structure and activity. In …
Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble
Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble
Doctoral Dissertations
This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …
Microbial Community Structure And Ecosystem Function In A Changing World, Melissa Ann Cregger
Microbial Community Structure And Ecosystem Function In A Changing World, Melissa Ann Cregger
Doctoral Dissertations
Understanding the effects climate change will have on the structure and function of global ecosystems is a pressing ecological and social issue. Global change driven changes in atmospheric warming and precipitation régimes have begun to alter the distribution of plants and animals in, as well as the function of, ecosystems. Using two large-scale climate change manipulations, I assessed the effect of changing precipitation and temperature regimes on soil microbial community structure and function. Soil microbial communities regulate decomposition and nutrient cycling rates in ecosystems, thus understanding their response to climatic changes will enable scientists to better predict carbon feedbacks to …
Tree Growth Dynamics, Fire History, And Fire-Climate Relationships In Pine Rocklands Of The Florida Keys, U.S.A., Grant Logan Harley
Tree Growth Dynamics, Fire History, And Fire-Climate Relationships In Pine Rocklands Of The Florida Keys, U.S.A., Grant Logan Harley
Doctoral Dissertations
Pine rocklands are globally endangered, fire-maintained communities currently restricted to small habitat areas in southern Florida, Cuba, and the Bahamas. The purpose of this dissertation research was to identify the long-term ecological disturbance regimes and climatic trends responsible for the persistence of pine rocklands, and examine how human-induced changes during the 20th century contributed to decline of these communities. This research applied techniques of dendrochronology in extreme southern Florida, in a subtropical region where tree‐ring science has never been applied, to increase the understanding of how anthropogenic and natural disturbance events have decreased the spatial distribution of South Florida …