Life Sciences Commons^™

Changing Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticuschanging Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticus, Clare Flynn

Pomona Senior Theses

Cassin’s auklet (Ptychoramphus aleuticus) reproductive success has been monitored on Southeast Farallon Island (SEFI) for the past 45 years. Their productivity has varied with oceanic conditions. The purpose of this study is to connect how oceanic conditions affect Cassin’s auklet foraging behaviors. The California Current System (CCS) can normally maintain high plankton productivity, and thus high seabird productivity, because of coastal upwelling. I hypothesized that lower upwelling and/or higher sea surface temperatures (SSTs) lead Cassin’s auklets to spend more time on intensive foraging behaviors such as flying and diving, and have less time to spend resting. I also hypothesized that …

The Independent And Combined Effects Of Hypoxia And Tributyltin On The Eastern Oyster, Crassostrea Virginica, Ann Fairly Barnett

Electronic Theses and Dissertations

Oysters are vital to the health of estuarine ecosystems and provide critical ecosystem services, such as water quality improvement, nursery habitat for commercially important fisheries, and shoreline stabilization. Despite their ecological and economic importance, oyster reefs are exposed to many stressors, and oyster populations in Mississippi have declined dramatically in recent years. The present study focuses on the effects of hypoxia and tributyltin (TBT) on the Eastern oyster, Crassostrea virginica. Hypoxic events are increasingly comin coastal ecosystems worldwide, and TBT is a legacy toxicant once used as an antifoulant. The effects of these stressors were assessed on adult oysters deployed …

Local Farmer Knowledge Of Adaptive Management On Diversified Vegetable And Berry Farms In The Northeastern Us, Alissa White

Graduate College Dissertations and Theses

Agricultural adaptation to climate change is notoriously context specific. Recently updated projections for the Northeastern US forecast increasingly severe and erratic precipitation events which pose significant risks to every sector of agricultural production in the region. Vegetable and berry farmers are among the most vulnerable to the risks of severe precipitation and drought due to the intensive soil and crop management strategies which characterize of this kind of production. To successfully adapt to a changing climate, these farmers need information which is tailored for the unique challenges of vegetable and berry production, framed at the level of climate impacts, and …

Future Forest Composition Under A Changing Climate And Adaptive Forest Management In Southeastern Vermont, Usa, Matthias Taylor Nevins

Graduate College Dissertations and Theses

Global environmental change represents one of the greatest challenges facing forest resource managers today. The uncertainty and variability of potential future impacts related to shifting climatic and disturbance regimes on forest systems has led resource managers to seek out alternative management approaches to sustain the long-term delivery of forest ecosystem services. To this end, forest managers have begun incorporating adaptation strategies into resource planning and are increasingly utilizing the outcomes of forest landscape simulation and climate envelope models to guide decisions regarding potential strategies to employ. These tools can be used alongside traditional methods to assist managers in understanding the …

Mitigating Gaseous Nitrogen And Carbon Losses From Northeastern Agricultural Soils Via Alternative Soil Management Practices, Kyle Michael Dittmer

Graduate College Dissertations and Theses

Traditional agricultural practices often result in gaseous losses of nitrous oxide (N2O), ammonia (NH3), and carbon dioxide (CO2), representing a net loss of nutrients from agricultural soils, which negatively impacts crop yield and requires farmers to increase nutrient inputs. By adopting best management practices (BMPs; i.e., no-tillage, cover crops, sub-surface manure application, and proper manure application timing), there is great potential to reduce these losses. Because N2O and CO2 are also greenhouse gases (GHGs), climate change mitigation via BMP adoption and emissions reductions would be an important co-benefit. However, adopting a no-tillage and cover cropping system has had setbacks within …

Evaluating Climate And Environmental Drivers Of Tree Species’ Growth Within The Northern Forest, Rebecca Stern

Graduate College Dissertations and Theses

Northeastern forests are in a period of immense change. While forests are inherently dynamic ecosystems, a range of environmental challenges may cause unique and uncertain transformations within forests moving forward. How trees in northern forests respond to these environmental and anthropogenic changes remains uncertain; reductions and increases in the growth of various species and shifts in current species’ ranges may take place.

I analyzed associations between tree growth (assessed using xylem increment cores) and a range of site, climate, and pollution deposition variables for seven major tree species in Vermont. First, I looked at red oak (Quercus rubra L.), a …

Influence Of Climate Change And Prescribed Fire On Habitat Suitability And Abundance Of The High-Elevation Endemic Cow Knob Salamander (Plethodon Punctatus), Carl David Jacobsen

Graduate Theses, Dissertations, and Problem Reports

Amphibians are facing global declines due to climate change, loss and degradation of habitat, invasive species, and disease. The Appalachian region of the eastern USA is a global biodiversity hotspot for salamanders, which are considered keystone species that influence nutrient dynamics in terrestrial and aquatic food webs. There are high rates of salamander endemism in the Appalachian region, with many species restricted to isolated, high elevation areas. The Cow Knob Salamander (Plethodon punctatus) is one such species. It is only found at elevations >675 m (most populations are above 900 m) on Shenandoah Mountain, North Mountain, and Nathaniel …

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Cal Poly Humboldt theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and …

Wetland Biogeochemical Responses To Predicted Climate Change Scenarios, Angela R. Shaffer

Electronic Theses and Dissertations

Wetlands are one of the world's largest known carbon sinks while comprising only a small amount of the Earth's surface. However, the amount of carbon sequestered by wetlands is shrinking as droughts and human disturbance increases. Carbon in wetlands is stored through the contrast of decomposition and sedimentation of organic matter and absorption of CO₂ from the atmosphere by soil microbes. Understanding how changing hydrological regimes and increased wildfires will affect wetland soil and microbial processes is important in the face of predicted climate change for future wetland conservation practices. Specifically, I seek to understand the response of southeastern …

Population Structure And Connectivity Of A Groundwater Crustacean Across Northwestern Montana Aquifers, Megan N. Ritter

Master’s Theses

Floodplain aquifer systems are diverse and heterogenous ecosystems that serve many ecological functions, including habitat provision to a range of groundwater species. The Flathead River system of northwestern Montana is home to many floodplain aquifers of great ecological importance to the region. The basic biology, population structure, and dispersal patterns of obligate groundwater organisms that reside within the aquifers of the Flathead are still largely unknown. In this study, we investigate the population structure of one such taxon, an undescribed species of the amphipod genus Stygobromus. For our low-coverage RADseq dataset, we tested the suitability of three different analysis …

Deciduous Shrub Encroachment Effects On Tundra Soil Properties, Daniela Aguirre

Open Access Theses & Dissertations

Deciduous shrub abundance is increasing in tundra ecosystems as an effect of rising temperatures which may change tundra physical properties and, in turn, microbial communities and biogeochemical processes. Two mechanisms through which shrub presence may affect tundra ecosystems were examined in this study; the physical presence of the shrubs and effects of increasing shrub litter inputs. In a sub-arctic alpine tundra ecosystem, dominated by the deciduous shrub Betula glandulosa, both shrub presence (shrub present and removed) and litter quantity (no litter/litter removed, ambient litter, and twice ambient litter) were manipulated; multiple ecosystem properties where measured within the treatment plots over …

Reexamining The Utility Of Existing Climate Adaptation Frameworks Through Application On A Northern Forest, Alexander Rice

Dissertations, Master's Theses and Master's Reports

A review of the literature reveals the strengths and limitations of various climate adaptation frameworks and illuminates a general path by which a type of adaptation can be achieved. A number of useful frameworks exist but the number of independent case studies demonstrating the adaptation process in a detailed manner is much more limited. Additionally, components of the various adaptation processes can often seem vague and concepts such as adaptability ill-defined. For land managers approaching climate adaptation independently can be difficult, particularly in the areas of goal creation and vulnerability assessment. Within frameworks where user-defined adaptation goals dictate whether or …

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …

Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh

Theses and Dissertations (Comprehensive)

The North American Great Plains is home to thousands of closed-basin lakes that are sensitive to changes in hydrology. Climate change models predict increased aridity in this region over the coming century, which is expected to lead to higher salinity levels in many freshwater lakes. Increases in salinity levels may impact zooplankton communities, as laboratory experiments show that many freshwater species have a low tolerance for elevated salinity levels, and field data demonstrate that salinity is the primary factor structuring aquatic communities on the Great Plains. Changes to zooplankton communities could lead to a trophic cascade based on their important …

Thermal And Low Oxygen Tolerance Of A Southern Population Of Striped Bass (Morone Saxatilis), Daniel A. Lleras

Electronic Theses and Dissertations

Climate change projections estimate a 2-3°C increase in water temperatures by the end of the century. The amount of habitat with suitable temperature and oxygen concentration for aquatic organisms will also be reduced. Striped bass (Morone saxatilis) inhabiting the rivers in Southeastern Georgia make an interesting study system as they do not participate in summer coastal migrations typical of their northern conspecifics. Instead, fish in this southern population remain in freshwater environments that experience warming and decreases in dissolved oxygen. The present study aims to determine the thermal and low oxygen tolerance of juvenile striped bass collected from …

Factors Influencing Zooplankton Communities In Small Arctic Lakes, Northwest Territories, Jasmina Vucic

Theses and Dissertations (Comprehensive)

The Canadian Arctic has been warming at an unprecedented rate, causing significant changes to the environment. At the same time, continued development in the north has increased the demand for gravel extraction used to construct and maintain infrastructure such as highways. The development of roadways and gradual loss of permafrost in Canada’s north has led to changes in water quality, including increased calcium, conductivity, and nutrients. In addition, gravel extraction has led to the formation of artificial gravel pit lakes. Research has yet to determine how physical and chemical changes associated with development and permafrost thaw might impact zooplankton, and …