Life Sciences Commons^™

A Sky Island Perspective: New England Alpine Plant Distributions Across The Region, Andrea Tirrell

Electronic Theses and Dissertations

Alpine ecosystems around the globe are at risk due to climate change, human disturbance, and habitat loss. New England alpine zones are small and fragmented, which could make them vulnerable to global change. However, the persistence of tundra relics throughout the Holocene suggests the persistence of these communities in microclimate refugia. Assessing the near-term vulnerability of alpine plant communities is challenged by a lack of standardized, repeat surveys and long-term monitoring data, which presents a challenge for the many agencies monitoring New England’s alpine zones. Island biogeography theory predicts that alpine species richness is a function of area, but this …

Landscape Genomics Of The Tussock Cottongrass (Eriophorum Vaginatum) And The Dwarf Birch (Betula Nana) In North Central Alaska, Elizabeth Stunz

Open Access Theses & Dissertations

Global climate change has resulted in geographic range shifts of flora and fauna at a global scale. Extreme environments, like the Arctic, are seeing some of the most pronounced changes. This region covers 14% of the Earthâ??s land area, and while many arctic species are widespread, understanding ecotypic variation at the genomic level will be important for elucidating how range shifts will affect ecological processes. Increase in shrub cover is a major effect of ongoing climate change in arctic tundra ecosystems. The relative increases in abundance and cover of shrub species such as birch, willow, and alder (Betula, Salix, and …

Atlantic Surfclam (Spisula Solidissima) Population Demographics And Distribution Along The Middle Atlantic Bight, Mauricio González Díaz

OES Theses and Dissertations

The Atlantic surfclam (Spisula solidissima) is a long-lived benthic biomass dominant organism that occurs on the Middle Atlantic Bight (MAB) continental shelf between 10 m and 50 m. Trends in Atlantic surfclam population specific growth and mortality rates were analyzed using four decades of age and length observations obtained from NOAA stock surveys from the 1980s to 2010s in six regions distributed along the MAB. Atlantic surfclam specific growth rates and asymptotic lengths were estimated from the age and length observations using the von Bertalanffy growth model. The analysis showed that the Atlantic surfclam median asymptotic length in …

Climate Impacts On North American Quail, Shelby M. Perry, Erin Moser, Jeffrey G. Whitt, Kelly S. Reyna

National Quail Symposium Proceedings

North America’s quail population trends are often linked to regional climate. Extreme climate events such as severe drought, hard freezes, or excessive winter precipitation can reduce quail populations by as much as 84%. Above-average spring and summer temperatures coincident with drought can reduce the laying season for quail by ≤60 days. Exposure of quail eggs to high temperatures during preincubation can initiate and alter embryonic development. Here, we review the impacts of extreme climate events and a changing climate on the survival, reproduction, and population trends of 6 North American quail species: California quail (Callipepla californica), Gambel’s quail …

Northern Bobwhite And Fire: A Review And Synthesis, David A. Weber, Evan P. Tanner, Theron M. Terhune Ii, J. Morgan Varner, James A. Martin

National Quail Symposium Proceedings

Our understanding of the relationship between northern bobwhite (Colinus virginianus; hereafter, bobwhite) and fire began with Herbert Stoddard’s work in the early 20th century. Research on the topic has continued, but our application of fire is deeply rooted in Stoddard’s work, even as it has become evident that fire regimes must be adapted to variable environmental conditions that are evolving with a changing landscape and climate. A comprehensive review and synthesis of the literature on this topic would help formalize research advancements since Stoddard and identify knowledge gaps for future research. Results from experiments suggest fire creates favorable …

Inside Insects - Climate Change And Metamorphosis, Cailyn R. Mckay

Undergraduate Student Research Internships Conference

Climate change is causing extreme environmental conditions including an increase in the frequency of heat waves which have the potential to seriously impact insect species, particularly during the sedentary pupal stage. The true armyworm is used here as a model species to evaluate the effects of simulated heat waves on reproductive activity and output later in life. Heat waves had a negative impact on moth reproduction and could be impacting the ecology of the species today and in the future.

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 …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

University of New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Chihuahuan Desert Rock Pool Community Assemblages: Patterns Of Taxonomic Diversity, Joseph Lee Mcdaniel

Open Access Theses & Dissertations

As climate change continues to become more prevalent, increasing temperatures and altering precipitation patterns will disrupt the environmental balance of ecosystems and spark the imminent threat of a 6th mass extinction event. Many researchers believe this has already begun, as losses for numerous taxonomic clades have been well documented; however, the loss of invertebrates is still unknown and may be much more severe than those of other animal clades. A significant factor contributing to the shortfall of invertebrate biodiversity loss is rooted in the lack of understanding of the diversity and distribution of these animals. There is still much to …

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 …

Hidden Mechanisms Of Climate Impacts In Western Forests: Integrating Theory And Observation For Climate Adaptation, Sara J. Germain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fire, insects, and disease are necessary components of forest ecosystems. Yet, climate change is intensifying these tree stressors and creating new interactions that threaten forest survival. This dissertation combined field observations with statistical predictions of changing disturbances in western forests to identify 1) how conventional models may underestimate future forest loss, and 2) how positive relationships between trees may be exploited by managers to prevent forest loss.

In Chapter II, I tested whether increasingly extreme weather with climate change increases Pacific yew extinction risk. I found that conventional modeling methods underestimated local extinction risk because trees were adapted to a …

Effects Of Forest Restoration On The Recovery Of Dead Wood, Associated Arthropods, And Insect-Mediated Wood Decomposition, Estefania Fernandez Barrancos

Dissertations

Dead wood represents 8% of terrestrial carbon stocks and is an important source of habitat and food for decomposer and non-decomposer arthropods. However, anthropogenic disturbance reduces the amount of dead wood, putting at risk the presence of a habitat that is essential for many arthropods and other organisms that rely on it for food and shelter. Forest restoration aims to assist the recovery of ecosystems that have been damaged or destroyed and could be a means to recover both dead wood and its associated arthropod communities. This doctoral dissertation lies at the intersection of climate change, biodiversity loss and ecological …

Impacts Of Sea Ice Loss On Polar Bear Diet, Prey Availability, Foraging Behaviors, And Human-Bear Interactions In The Arctic, Jasmin Chen

Master's Projects and Capstones

Anthropogenic-induced climate change has warmed the Arctic 2-3 times faster than the rest of the world, causing sea ice declines that introduce challenges for specialist species, such as polar bears, in adapting to rapid environmental changes. Comparative and quantitative analyses of three Hudson Bay polar bear subpopulations were used to determine the impacts of sea ice loss on polar bear diet, prey availability, foraging behaviors, and human-bear interactions in the Arctic. The study reveal that Hudson Bay polar bears experience the most severe impacts from sea ice declines, resulting in a 30% population decline. Due to their smaller body size, …

How Environmental Change Will Impact Mosquito-Borne Diseases, Arsal Khan

Master's Projects and Capstones

Mosquitos, the most lethal species throughout human history, are the most prevalent source of vector-borne diseases and therefore a major global health burden. Mosquito-borne disease incidence is expected to shift with environmental change. These changes can be predicted using species distribution models. With the wide variety of methods used for models, consensus for improving accuracy and comparability is needed. A comparative analysis of three recent modeling approaches revealed that integrating modeling techniques compensates for trade-offs associated with a singular approach. An area that represents a critical gap in our ability to predict mosquito behavior in response to changing climate factors, …

Biodiversity And Global Change In Terrestrial Ecosystems, Timothy J. 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 …

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 …

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 …

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 …

Communicating Climate Change Through Dance, Alexandra M. Ryan

Honors College

The purpose of this thesis is to study how viewers react to seeing climate issues communicated through dance. Past research states that an effective climate communicator is not necessarily an expert, but a person who uses their platform to create a dialogue, and encourages public engagement with climate change by making the issues interesting and appealing to viewers. With this criterion in mind, three short dance videos were made surrounding three relevant climate issues. Along with climate topic inspired choreography, these videos contained written information regarding coral bleaching, air travel emissions, and renewable energy. These videos were posted to the …

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 …

From Individuals To Communities: The Effect Of Climate Change On Ectothermic Predators, Matthew Lawrence Meehan

Electronic Thesis and Dissertation Repository

The living components of ecological systems exist within a nested hierarchy, consisting of individuals, populations, and communities. Because of this nestedness, climate change can greatly impact ecological systems, as whole-organism metabolic and physiological demands change for ectotherms under warming, the effects of which may compound with every succeeding level. Therefore, a multi-level approach can better isolate how climate change will reshape ecological systems. In my doctoral research, I used feeding and mesocosm experiments to examine how climate change affects ectothermic predators at the individual-, population-, and community-level, using mesostigmatic mites (Arachnida: Parasitiformes) as my model predator. My research objectives were …

The Influence Of Climate Change On The Ecology Of The Arctic Ground Squirrel In Denali National Park, Ak., Nigel A. Golden

Doctoral Dissertations

This dissertation research focuses on the ecology of the Arctic ground squirrel (Urocitellus parryii) in Denali National Park and Preserve, AK. The Arctic ground squirrels is a species of interest for monitoring efforts under the National Park Services’ Vital Signs Monitoring Program under the Vital Signs Monitoring program. The focus of this program is to monitor what is considered to be the most significant indicators of ecological conditions of the specific park resources that are of the greatest concern. The CAKN designated the Arctic ground squirrel (Urocitellus parryii) as one indicator species of park ecosystems. Despite being easy to observe …

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 …

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 …

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

Antioch University Full-Text 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 …

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. …

Bottom-Up Drivers Of Future Fire Regimes In Western Boreal North America, Adrianna C. Foster, Jacquelyn K. Shuman, Brendan M. Rogers, Xanthe J. Walker, Michelle C. Mack, Laura L. Bourgeau-Chavez, Sander Veraverbeke, Scott J. Goetz

Aspen Bibliography

Forest characteristics, structure, and dynamics within the North American boreal region are heavily influenced by wildfire intensity, severity, and frequency. Increasing temperatures are likely to result in drier conditions and longer fire seasons, potentially leading to more intense and frequent fires. However, an increase in deciduous forest cover is also predicted across the region, potentially decreasing flammability. In this study, we use an individual tree-based forest model to test bottom-up (i.e. fuels) vs top-down (i.e. climate) controls on fire activity and project future forest and wildfire dynamics. The University of Virginia Forest Model Enhanced is an individual tree-based forest model …

Identifying Conifer Tree Vs. Deciduous Shrub And Tree Regeneration Trajectories In A Space-For-Time Boreal Peatland Fire Chronosequence Using Multispectral Lidar, Humaira Enayetullah, Laura Chasmer, Christopher Hopkinson, Dan Thompson, Danielle Cobbaert

Aspen Bibliography

Wildland fires and anthropogenic disturbances can cause changes in vegetation species composition and structure in boreal peatlands. These could potentially alter regeneration trajectories following severe fire or through cumulative impacts of climate-mediated drying, fire, and/or anthropogenic disturbance. We used lidar-derived point cloud metrics, and site-specific locational attributes to assess trajectories of post-disturbance vegetation regeneration in boreal peatlands south of Fort McMurray, Alberta, Canada using a space-for-time-chronosequence. The objectives were to (a) develop methods to identify conifer trees vs. deciduous shrubs and trees using multi-spectral lidar data, (b) quantify the proportional coverage of shrubs and trees to determine environmental conditions driving …

Investigating The Effects Of Climate Change On The Phenology Of Achillea Millefolium, Aquilegia Coerulea, And Penstemon Cyanocaulis, Hannah O’Toole, Kailey Hicks, Lisa Long, Jackson Garske, Anna Sher

DU Undergraduate Research Journal Archive

As the effects of climate change are starting to unearth themselves, the impacts can be observed by tracking the patterns of cyclical natural phenomena also known as phenology, and monitoring how they have changed over time. These cycles are at the crux of making ecosystems viable for their local biodiversity, and understanding the ongoing change allows for further understanding of the ecosystem’s change over time. In this study, we look at the ordinal flowering dates of the Achillea millefolium, Aquilegia coerulea, and Penstemon cyanocaulis over the past century. Our data give insight into how warmer temperatures occurring earlier in …

Revealing The Direct And Indirect Effects Of Climate Change On Soil Nutrient Dynamics And Forage Resources In Mountain Ecosystems, Kenna Elizabeth Rewcastle

Graduate College Dissertations and Theses

Modern climate change is already altering the structure and function ofecosystems around the world in nontrivial ways. Mountain ecosystems in particular will continue to experience a greater magnitude and rate of climatic warming than the global average, threatening the stability of key ecosystem processes like nutrient cycling as well as the supply of benefits from ecosystem services provided by mountains. While significant advancements have been made to address the direct effects of rising temperatures on nutrient cycling dynamics, our understanding of the synergies between the direct effects of warming and the indirect effects of climate change, mediated by the response …