Life Sciences Commons^™

Marine Population Connectivity: Range Boundaries And Climate Change, Rhiannon Leigh Rognstad

Theses and Dissertations

Population connectivity, particularly in open systems, is an important metric for understanding population-level processes on both ecological and evolutionary timescales. In coastal marine systems, adults are typically sedentary and dispersal occurs primarily during a larval stage when individuals are transported in ocean currents. Because coastal marine populations exist as networks of interconnected subpopulations, variation in the magnitude and extent of population connectivity can have profound effects on population dynamics and species distribution limits. Connectivity is a complex process, affected by a multitude of factors, including adult inputs and physical dispersal, which operate at multiple scales and may interact. This dissertation …

Thermal Ecology And Physiology Of An Intertidal Predator-Prey System: Pisaster Ochraceus And Mytilus Californianus, Cristian J. Monaco

Theses and Dissertations

Untangling natural systems’ complexity requires understanding the mechanisms responsible for organisms’ responses to environmental change. Recently, significant advances have been made by recognizing the relevance of direct and indirect effects, which take place when multiple biotic and abiotic factors influence each other. I examined potential direct effects of environmental variables on a predator-prey interaction, as well as potential indirect effects of these variables on the interaction itself. I placed emphasis on behavioral and physiological adaptations, which would potentially contribute/modify these effects. My study system was comprised of a rocky intertidal keystone predator, the sea star Pisaster ochraceus, and its main …

Small Mammals Matter? Linking Plant Invasion, Biotic Resistance, And Climate Change In Post-Fire Plant Communities, Rory Charles O'Connor

Theses and Dissertations

The introduction and establishment of exotic species can profoundly alter ecosystems. Two exotic species drastically changing the landscape of deserts in western North America are Bromus tectorum L. and Bromus rubens L. Through the buildup of biomass and slow decomposition rates in deserts these two exotic annual grasses can alter fire regimes that change the plant and animal community dynamics in the ecosystems. To better understand the ecological mechanisms that could restrict or alter the patterns of invasive plant establishment we established a replicated full factorial experiment in the Great Basin and Mojave Desert. The combinations of factors being manipulated …

Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo

Doctoral Dissertations

Assessment and management of ecosystem services demands diverse knowledge of the system components. Land use change occurring mainly through deforestation, expansion of agriculture and unregulated extraction of natural resources are the greatest challenges of the Congo basin and yet is central to supporting over 100 million people. This study undertook to implement an integrated modeling of multiscale ecosystems of central African watersheds and model the impact of anthropogenic factors on elephant population in Greater Virunga landscape. The study was conducted at varied scales, regional, landscape, and community. Regional study included watershed analysis and hydrological assessment using remotely sensed data implemented …

Landscape Predictors Of Current And Future Distribution Of Mountain Gorillas (Gorilla Beringei Beringei) In Bwindi Impenetrable National Park, Uganda, Dennis Babaasa

Doctoral Dissertations

Context: The impacts of ecological, anthropogenic and future climate change on the distribution of wild mountain gorillas (Gorilla beringei beringei) are of ongoing concern. Knowing the factors that determine gorilla habitat suitability now and in future is essential for conservation planning. The mountain gorilla is recognized by IUCN Red Data Book as critically endangered and a great tourist attraction. However, the factors that impact on their spatial use of Bwindi are poorly understood. Aims: I aimed at determining the major factors that determine gorilla distribution, predict the wild gorilla habitat suitability and establish the vulnerability index …

The Effects Of Global Climate Change On Canadian Boreal Forest Collembola Communities, Matthew S. Turnbull

Electronic Thesis and Dissertation Repository

Soil fauna are an integral component of terrestrial ecosystem function. The effects of global environmental change on soil biodiversity are poorly studied, particularly interactions among temperature, atmospheric CO₂, precipitation intensity, and nutrient loading. Body size distributions can be used to quantify soil community responses to perturbation and consequences for ecosystem function. I quantified top-down and bottom-up effects of environmental change on the abundance, richness, and size distribution of the soil microarthropod group Collembola. I demonstrated negative effects in a lab experiment of increased precipitation on collembolan density and richness across all size groups. I demonstrated positive effects in …

Wetland Sediment Nutrient Flux In Response To Proposed Hydrologic Reconnection And Climate Warming, James T. Smit

Masters Theses

Wetland restoration and creation are common practices, but wetlands restored or created on former agricultural land may act as a source of nutrients, rather than as a sink. I studied P sediment-water exchange in two flooded celery fields (west and east), which are designated for wetland restoration, in order to assess the effects that hydrologic reconnection of the area to an adjacent creek would have on P dynamics. We also examined the influence of climate change, specifically warming temperatures, by conducting the sediment-water exchange experiments at ambient and plus 2°C temperature conditions. Lab-based sediment core incubations revealed that TP release …

Establishment Of Larrea Tridentata At The Northern Edge Of The Modern Mojave Desert: Insights From Neotoma Paleomiddens, Clare Steinberg

Biology ETDs

Shifting climates affect the composition of biological communities. If environmental conditions change sufficiently, new species can invade, leading to large-scale community turnover. Understanding how and why such shifts occur is crucial in this era of anthropogenic global change. Paleontological studies provide a valuable long-term perspective of the dynamics of community turnover. Here, we examine changes in the plant community over the past 34 thousand years in what is now the northern Mojave Desert. This time period includes the last glacial maximum as well as numerous smaller climatic fluctuations in the Holocene and the end of the Pleistocene. We quantified plant …

The Adaptive Capacity Of Thermal Tolerance In Chinook Salmon, Nicolas Muñoz

Electronic Thesis and Dissertation Repository

With global temperatures projected to surpass the limits of thermal tolerance for many species, evaluating the capacity for evolutionary and phenotypically plastic changes in thermal tolerance is key to our understanding of the biological consequences of climate change. Within quantitative genetic breeding designs and multiple rearing environments, I measured the thermal performance of cardiac function among families of two populations of chinook salmon (Oncorhynchus tshawytscha). I found significant indirect genetic, plastic, and additive genetic effects contributing to cardiac performance and thermal tolerance, representing a variety of adaptive mechanisms available to salmon populations faced with climate change. These results …

Changes In Spring Arrival And Fall Departure Dates Of Migratory Birds As An Indication Of Local Climate Change: A Phenological Study Of New York State's Capital Region Using Citizen Science, Olivia C. Townsend

Honors Theses

Climate change is becoming an increasingly important topic of scientific research, and studies commonly analyze biological indicators. Migratory birds are responsive to environmental changes because life cycles depend on finding proper seasonal locations. eBird is a citizen science database launched by the Cornell Lab of Ornithology and National Audubon Society in 2002, and this study focused on eBird data to analyze migratory shifts over the past two decades for the Green-winged Teal (Anas crecca), Northern Pintail (Anas acuta), Bufflehead (Bucephala albeola), Common Goldeneye (Bucephala clangula), Common Merganser (Mergus merganser), Red-breasted Merganser (Mergus serrator), Canada Goose (Branta canadensis), Snow Goose (Chen …

Assessment Of Climate Variability Impact On Water Resources Within The Alabama River Basin, Adalumo Oluwatomiwa

College of Agriculture, Environment and Nutrition Sciences Graduate Theses and Dissertations

ABSTRACT

Assessment of Climate Variability Impacts on Water Resources within the Alabama River Basin By Adalumo Oluwatomiwa Olubamidele Global climate change and variability alters hydrologic cycles and regimes within watersheds, adversely impacting ecosystems, water resources, agriculture and environmental sustainability. Understanding and predicting the interactions between the water systems, climate change and land use are priority science need and challenge areas. Such assessment through the integration of various climate and hydrologic models will allow for the development of appropriate climate change impact adaptation solutions. This study aims at assessing historical climate variability impacts on water resources within the Alabama River Basin. …

Inferring Herpetofaunal Distributions And Habitat Preferences For Conservation Planning, Lisa M. Prowant

Master's Theses

Global climate change is a serious threat to global biodiversity (IPCC, 2001). Due to their limited dispersal ability, reptiles and amphibians might be more vulnerable to rapid climate change than are other taxonomic groups (Gibbons et al., 2000). Herpetofauna in south-central Kansas was sampled from May through August in 2012 and 2013. Seven study sites spanning Meade, Clark, Comanche, and Barber counties were sampled. Drift fence and cover-board traps were arranged in transects at each site to capture reptiles and amphibians. Species were also sampled through surveys on all-terrain vehicles and on foot. Two thousand nine hundred and forty five …

Population Response To Climate Change: Wintering Strategy Has Carryover Effects On The Timing Of Nest Initiation And Mate Choice In A Partial Migrant, The American Kestrel (Falco Sparverius), Alexandra Marie Anderson

Boise State University Theses and Dissertations

The ability of a population to respond to climate change will depend on phenotypic plasticity, adaptation, or both. Bird populations have already responded to warming temperatures by shifting their distributions, adjusting migration distance and timing, and breeding earlier. A population of American kestrels (Falco sparverius) in southwestern Idaho has advanced its nesting by approximately 30 days, on average, in the last 30 years and this has been correlated with changes in winter climate. The mechanisms allowing for this shift, however, are not clearly understood. I investigated if assortative mating of wintering kestrels and non-wintering kestrels is accompanying to …

Effects Of Climate Change On The Potential Distribution Of 12 Endemic Lizards Of The Genus Plestiodon Of Mexico, Mayra Oyervides

Theses and Dissertations - UTB/UTPA

Anthropogenic global climate change is a large scale threat to biodiversity. Species distribution models (SDMs) were created to assess the possible effects of climate change on the distribution of 12 Plestiodon lizards of Mexico. Species presence data was obtained from online databases, literature, and field data. Occurrences were correlated with 19 climatic variables from www.worldclim.org to model species' current suitable habitat. These models were then projected to future (2050) conditions for which bioclimatic information was downloaded from the CCAFS website. Forecasts were made using 4 General Circulatory Models, 2 IPCC scenarios, and the software MaxEnt. Models were replicated 10 times …

Range Collapse, Genetic Differentiation, And Climate Change: An Ecological History Of The Diana Fritillary, Speyeria Diana And Projections For Its Future, Carrie Wells

All Dissertations

The geographic ranges of most plant and animal species are tied closely to climatic factors, including temperature, precipitation, and soil moisture. For this reason, recent changes in the global climate due to human activities are predicted to have profound effects on natural populations, communities and ecosystems over a relatively short period of time. Combined effects from global warming and other anthropogenic activities such as land-use changes, pollution, and habitat loss/fragmentation, are altering species' distributions faster than they can be documented. Recent climate change has also been shown to alter species' breeding behaviors and alter the synchrony and timing of species' …

Post-Den Emergence Behavior And Den Detection Of Polar Bears (Ursus Maritimus) In Northern Alaska And The Southern Beaufort Sea, Rusty Wade Robinson

Theses and Dissertations

Pregnant polar bears (Ursus maritimus) construct maternal dens out of snow in the autumn where they give birth to and raise altricial young. In recent years, there has been a decrease in polar sea ice extent and thickness, which has led to changes in denning behavior. One such change in the southern Beaufort Sea (SBS) is that polar bears are selecting maternal den sites on land, rather than on unstable sea ice. This change, coupled with expanding petroleum exploration along Alaska's North Slope, heightens the likelihood of bear-human interactions at maternal den sites. The purpose of this research …

Migration Plasticity As An Adaptation To Climate Change: The Spatial Distribution And Abundance Of A Subset Of Neotropical Migrant Landbirds Wintering In The Northeastern United States, Juliette Goulet

Dissertations, Theses, and Capstone Projects

There is a need for accurate predictions of the effects of climate change on wildlife populations. Bioclimatic relationships however are potentially complicated by various environmental factors operating at multiple spatial and temporal scales. Therefore, in order to test the hypothesis that climate constraints of winter bird distributions are modified by species-specific responses to weather and climate, I relied on Christmas Bird Count data (CBC). With nearly 100 years of data, the CBC is a valuable source of information on historic and recent changes in the status and distribution of birds during the early winter period in the United States and …

How Important Is Land-Based Foraging To Polar Bears (Ursus Maritimus) During The Ice-Free Season In Western Hudson Bay? An Examination Of Dietary Shifts, Compositional Patterns, Behavioral Observations And Energetic Contributions, Linda J. Gormezano

Dissertations, Theses, and Capstone Projects

Trophic mismatches between predators and their prey are increasing as climate change causes decoupling of phenological relationships. Predators linked to the life histories of a particular prey will have a more difficult time persisting through environmental change unless they can alter their behavior to maintain the historical match or possess the ability to pursue alternate prey. Arctic predators typically possess flexible foraging strategies to survive in the labile environment, however, quantifying the limits of those strategies can be difficult when life history information is incomplete. In such cases, piecing together different aspects of a predator's foraging behavior, particularly when environmental …

The Impacts Of Multiple Anthropogenic Disturbances On The Montane Forests Of The Green Mountains, Vermont, Usa, Carolyn Ann Pucko

Graduate College Dissertations and Theses

How and why species’ ranges shift has long been a focus of ecology but is now becoming increasingly important given the current rate of climatic and environmental change. In response to global warming, species will need to migrate northward or upward to stay within their climatic tolerances. The ability of species to migrate will determine their fate and affect the community compositions of the future. However, to more accurately predict the future extent of species, we must identify and understand their responses to past and current climatic and environmental changes. The first place change is expected to occur is within …

Grassland Sustainability In Kentucky: Case Studies Quantifying The Effects Of Climate Change On Slug Herbivory In Pastures And Different Home Lawn Systems On Turf Greenhouse Gas Emissions, Daniel Adam Weber

Theses and Dissertations--Plant and Soil Sciences

Grasslands comprise the greatest biome by land area, are sensitive to environmental factors affected by climate change, and can impact future climate change through their ability to store and release greenhouse gasses (GHGs). I performed two studies: 1) evaluated the effects of increased temperature and precipitation on slug herbivory/abundance and pasture forage production; 2) quantified different homeowner lawn system effects on soil-to-atmosphere GHG emissions. Climate change will likely affect pasture forage production, with implications for slug herbivory and abundance. I found little evidence that slugs have or will have significant effects on pasture production or plant community. Warming altered the …

Approaches To Restoration: Assessing The Roles Of Structure And Function In Saltmarsh Restoration In Light Of Climate Change, Abby O. Pearson Ms

All Student Scholarship

The aim of this thesis is to review the current goals and methods for salt marsh restoration, to question how those goals and methods may change in light of global change, and to present a case study that offers a look at the kinds of information that can be gleaned by studying both structure and functionality in restoration.

Musical Chairs In A Boreal Peatland: How Permafrost Thaw Reverses Successional Processes, Mélissa M. Fafard

Theses and Dissertations (Comprehensive)

The current climate trends indicate amplified high latitude warming. Boreal peatlands can be found within those high latitudes and have important functions hydrologically, ecologically and also in terms of carbon cycling. Peatland’s are wetlands that have accumulated more than 40 cm of peat and can range from minerotrophic fens to ombrotrophic bogs. Naturally, a rich fen can be converted to a bog once groundwater sources are cut off by Sphagnum spp. In areas underlain by discontinuous permafrost, landscape changes are occurring particularly rapidly as the permafrost there is sensitive to both vertical and horizontal thaw. The purpose of this thesis …

Wetlands And Greenhouse Gas Fluxes: Causes And Effects Of Climate Change – A Meta-Analysis, Robert E. Ventura

Pomona Senior Theses

Climate change is one of the largest problems facing this generation. Anthropogenically caused increases of greenhouse gas emissions is a significant culprit to this problem. Although the obvious problems such as cars, industry, and urbanism garnish a significant amount of the criticism, natural sources such as wetlands are also beginning to contribute to this issue. This is becoming increasingly significant as wetlands shift from being sinks of greenhouse gases to becoming sources as various anthropogenic impacts, including global warming itself, begin to affect the health of the wetlands. The aim of this project is to look at four common types …