Life Sciences Commons^™

Cold Hardiness And Deacclimation Of Overwintering Papilio Zelicaon Pupae, Caroline M. Williams, Nicolai Annegret, Brent J. Sinclair, Laura V. Ferguson, Mark A. Bernards, Jessica J. Hellmann

Biology Publications

Seasonally-acquired cold tolerance can be reversed at warm temperatures, leaving temperate ectotherms vulnerable to cold snaps. However, deacclimation, and its underlying mechanisms, has not been well-explored in insects. Swallowtail butterflies are widely distributed but in some cases their range is limited by low temperature and their cold tolerance is seasonally acquired, implying that they experience mortality resulting from deacclimation. We investigated cold tolerance and hemolymph composition of Anise swallowtail (Papilio zelicaon) pupae during overwintering in the laboratory, and after four days exposure to warm temperatures in spring. Overwintering pupae had supercooling points around − 20.5 °C and survived …

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 …

Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González

Steven J. Hall

Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …

Collapse Of An Ecological Network In Ancient Egypt, Justin Yeakel, Mathias Pires, Lars Rudolf, Nathaniel Dominy

Dartmouth Scholarship

The dynamics of ecosystem collapse are fundamental to determining how and why biological communities change through time, as well as the potential effects of extinctions on ecosystems. Here, we integrate depictions of mammals from Egyptian antiquity with direct lines of paleontological and archeological evidence to infer local extinctions and community dynamics over a 6,000-y span. The unprecedented temporal resolution of this dataset enables examination of how the tandem effects of human population growth and climate change can disrupt mammalian communities. We show that the extinctions of mammals in Egypt were nonrandom and that destabilizing changes in community composition coincided with …

Breeding Time In A Migratory Songbird Is Predicted By Drought Severity And Group Size, Charles R. Brown, Mary Bomberger Brown

School of Natural Resources: Faculty Publications

Global climate change is altering the breeding phenology of many organisms, and one reported consequence of warmer average temperatures is earlier breeding times in migratory songbirds of north temperate latitudes. Less studied are the potential interactions between earlier breeding and social behavior in colonial species. We investigated how breeding time, as measured by colony initiation dates across the entire summer, in Cliff Swallows (Petrochelidon pyrrhonota) of southwestern Nebraska, USA, changed over a 30-year period and could be predicted by climatic variables, year, and colony size. Mean colony initiation date became earlier over the study, with variation best predicted …

Warming, Competition, And Bromus Tectorum Population Growth Across An Elevation Gradient, Aldo Compagnoni, Peter B. Adler

Green Canyon Environmental Research Area, Logan Utah

Cheatgrass (Bromus tectorum) is one of the most problematic invasive plant species in North America and climate change threatens to exacerbate its impacts. We conducted a two‐year field experiment to test the effect of warming, competition, and seed source on cheatgrass performance across an elevation gradient in northern Utah. We hypothesized that warming would increase cheatgrass performance, but that warming effects would be limited by competing vegetation and by local adaptation of cheatgrass seed sources. The warming treatment relied on open top chambers, we removed vegetation to assess the effect of competition from neighboring vegetation, and we reciprocally …

Natural Selection On Thermal Performance In A Novel Thermal Environment, Michael L. Logan, Robert M. Cox, Ryan Calsbeek

Dartmouth Scholarship

Tropical ectotherms are thought to be especially vulnerable to climate change because they are adapted to relatively stable temperature regimes, such that even small increases in environmental temperature may lead to large decreases in physiological performance. One way in which tropical organisms may mitigate the detrimental effects of warming is through evolutionary change in thermal physiology. The speed and magnitude of this response depend, in part, on the strength of climate-driven selection. However, many ectotherms use behavioral adjustments to maintain preferred body temperatures in the face of environmental variation. These behaviors may shelter individuals from natural selection, preventing evolutionary adaptation …

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 …

A Threat To New Zealand's Tuatara Heats Up, Kristine L. Grayson, Nicola J. Mitchell, Nicola J. Nelson

Biology Faculty Publications

No matter how many times we head to one of New Zealand's offshore islands, the feelings are always a mix of sheer awe at the beauty and biodiversity preserved in these special refuges and lingering nerves. Did we remember all the gear? Do we have enough food and water in case we get stuck? Can the helicopter land on the side of a cliff in these winds? These epic journeys are in pursuit of a lone remnant of the reptile evolutionary tree, with a unique ecology that has big implications under climate change.

Precipitation Variability And Nitrogen Deposition Alter Root Distribution In A Tallgrass Prairie, Emmalyn P. Terracciano, Michael Schuster, Jeffrey Dukes

The Summer Undergraduate Research Fellowship (SURF) Symposium

Climate change and increases in nitrogen deposition impact ecosystems globally. Projected atmospheric warming allows rain to fall in larger events with longer dry periods in between, increasing rainfall variability in many regions. Concurrently, the combustion of fossil fuels and the heavy use of nitrogen fertilizers continue to increase the availability of nitrogen globally. However, not much is known about how these global change factors, increased rainfall variability and nitrogen deposition, interact with each other to affect ecosystem functions, particularly belowground where root production contributes to soil carbon pools- an important component in regulating climate. In order to study these factors, …

Ecological Biogeography Of The Terrestrial Nematodes Of Victoria Land, Antarctica, Byron Adams, Diana Wall, Ross Virginia, Emma Broos, Matthew A. Knox

Dartmouth Scholarship

The terrestrial ecosystems of Victoria Land, Antarctica are characteristically simple in terms of biological diversity and ecological functioning. Nematodes are the most commonly encountered and abundant metazoans of Victoria Land soils, yet little is known of their diversity and distribution. Herein we present a summary of the geographic distribution, habitats and ecology of the terrestrial nematodes of Victoria Land from published and unpublished sources. All Victoria Land nematodes are endemic to Antarctica, and many are common and widely distributed at landscape scales. However, at smaller spatial scales, populations can have patchy distributions, with the presence or absence of each species …

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 …

Climate And Land Use Controls On Soil Organic Carbon In The Loess Plateau Region Of China, Yaai Dang, Wei Ren, Bo Tao, Guangsheng Chen, Chaoqun (Crystal) Lu, Jia Yang, Shufen Pan, Guodong Wang, Shiqing Li, Hanqin Tian

Chaoqun (Crystal) Lu

The Loess Plateau of China has the highest soil erosion rate in the world where billion tons of soil is annually washed into Yellow River. In recent decades this region has experienced significant climate change and policy-driven land conversion. However, it has not yet been well investigated how these changes in climate and land use have affected soil organic carbon (SOC) storage on the Loess Plateau. By using the Dynamic Land Ecosystem Model (DLEM), we quantified the effects of climate and land use on SOC storage on the Loess Plateau in the context of multiple environmental factors during the period …

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 …

Sex Ratio Bias And Extinction Risk In An Isolated Population Of Tuatara (Sphenodon Punctatus), Kristine L. Grayson, Nicola J. Mitchell, Joanne M. Monks, Susan N. Keall, Joanna N. Wilson, Nicola J. Nelson

Biology Faculty Publications

Understanding the mechanisms underlying population declines is critical for preventing the extinction of endangered populations. Positive feedbacks can hasten the process of collapse and create an ‘extinction vortex,’ particularly in small, isolated populations. We provide a case study of a male-biased sex ratio creating the conditions for extinction in a natural population of tuatara (Sphenodon punctatus) on North Brother Island in the Cook Strait of New Zealand. We combine data from long term mark-recapture surveys, updated model estimates of hatchling sex ratio, and population viability modeling to measure the impacts of sex ratio skew. Results from the mark-recapture …

Exposure Of U.S. National Parks To Land Use And Climate Change 1900-2100, Andrew J. Hansen, Cory Davis, Jessica Haas, David M. Theobald, John E. Gross, William B. Monahan, Tom Olliff, Steven W. Running

Ecosystem and Conservation Sciences Faculty Publications

Many protected areas may not be adequately safeguarding biodiversity from human activities on surrounding lands and global change. The magnitude of such change agents and the sensitivity of ecosystems to these agents vary among protected areas. Thus, there is a need to assess vulnerability across networks of protected areas to determine those most at risk and to lay the basis for developing effective adaptation strategies. We conducted an assessment of exposure of U.S. National Parks to climate and land use change and consequences for vegetation communities. We first defined park protected-area centered ecosystems (PACEs) based on ecological principles. We then …

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 …

Religion, Partisanship, And Attitudes Toward Science Policy, Ted G. Jelen, Linda A. Lockett

Political Science Faculty Research

We examine issues involving science which have been contested in recent public debate. These “contested science” issues include human evolution, stem-cell research, and climate change. We find that few respondents evince consistently skeptical attitudes toward science issues, and that religious variables are generally strong predictors of attitudes toward individual issues. Furthermore, and contrary to analyses of elite discourse, partisan identification is not generally predictive of attitudes toward contested scientific issues.

Warming, Soil Moisture, And Loss Of Snow Increase Bromus Tectorum’S Population Growth Rate, Aldo Compagnoni, Peter B. Adler

Green Canyon Environmental Research Area, Logan Utah

Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum) is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1) warming increases cheatgrass population growth rate and 2) reduced snow cover contributes to cheatgrass’ positive response to …

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 …

Monteverde: Ecology And Conservation Of A Tropical Cloud Forest - 2014 Updated Chapters, Nalini M. Nadkarni, Nathaniel T. Wheelwright

Bowdoin Scholars' Bookshelf

The Monteverde Cloud Forest Reserve has captured the worldwide attention of biologists, conservationists, and ecologists and has been the setting for extensive investigation over the past 40 years. Roughly 40,000 ecotourists visit the Cloud Forest each year, and it is often considered the archetypal high-altitude rain forest. “Monteverde: Ecology and Conservation of a Tropical Cloud Forest”, edited by Nalini Nadkarni and Nathaniel T. Wheelwright (Oxford University Press, 2000 and Bowdoin’s Scholar’s Bookshelf. Book 1 ), features synthetic chapters and specific accounts written by more than 100 biologist and local residents, presenting in a single volume everything known in 2000 about …

On The Challenges Of Modeling The Net Radiative Forcing Of Wetlands: Reconsidering Mitsch Et Al. 2013, Scott C. Neubauer

Biology Publications

Wetlands play a role in regulating global climate by removing carbon dioxide (CO2) from the atmosphere and sequestering it as soil carbon, and by emitting methane (CH4) and nitrous oxide (N2O) to the atmosphere. In a recent article in this journal (Mitsch et al. Landscape Ecol 28:583–597, 2013), CO2 sequestration and CH4 emissions were modeled for several freshwater wetlands that vary in vegetation type, climate, and hydrology. The authors of that study made significant errors that caused them to underestimate the importance of wetland CH4 emissions on climate dynamics. Here, I reanalyze the Mitsch et al. dataset and show that …

Effects Of Disturbance And Climate Change On Ecosystem Performance In The Yukon River Basin Boreal Forest, Bruce K. Wylie, Matthew Rigge, Brian Brisco, Kevin Murnaghan, Jennifer A. Rover

Bruce K. Wylie

A warming climate influences boreal forest productivity, dynamics, and disturbance regimes. We used ecosystem models and 250 m satellite Normalized Difference Vegetation Index (NDVI) data averaged over the growing season (GSN) to model current, and estimate future, ecosystem performance. We modeled Expected Ecosystem Performance (EEP), or anticipated productivity, in undisturbed stands over the 2000–2008 period from a variety of abiotic data sources, using a rule-based piecewise regression tree. The EEP model was applied to a future climate ensemble A1B projection to quantify expected changes to mature boreal forest performance. Ecosystem Performance Anomalies (EPA), were identified as the residuals of the …

Drought-Induced Woody Plant Mortality In An Encroached Semi-Arid Savanna Depends On Topoedaphic Factors And Land Management, Dirac L. Twidwell Jr, Carissa L. Wonkka, Charles A. Taylor, Chris B. Zou, Jeremiah J. Twidwell, William E. Rogers

Department of Agronomy and Horticulture: Faculty Publications

Questions: How do recent patterns of drought-induced woody plant mortality in Texas semi-arid savanna compare to the extended drought of the 1950s? Does the relative composition of the woody plant community shift ubiquitously across the landscape following woody plant mortality and dieback or are shifts dependent on differences among species, soils, land use and plant demography?

Location: Texas Agrilife Research Station, Sonora, Texas, USA (30.1° N 100.3° W).

Methods: Following an exceptional drought from 1951 to 1957, a study was conducted to quantify rates of mortality for various woody plant species. In 2011, we repeated this study within three long-term …

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 …

Lineage-Specific Transcriptional Profiles Of Symbiodinium Spp. Unaltered By Heat Stress In A Coral Host, Daniel J. Barshis, Jason T. Ladner, Thomas A. Oliver, Stephen R. Palumbi

Biological Sciences Faculty Publications

Dinoflagellates of the genus Symbiodinium form an endosymbiosis with reef building corals, in which photosynthetically derived nutrients comprise the majority of the coral energy budget. An extraordinary amount of functional and genetic diversity is contained within the coral-associated Symbiodinium, with some phylotypes (i.e., genotypic groupings), conferring enhanced stress tolerance to host corals. Recent advances in DNA sequencing technologies have enabled transcriptome-wide profiling of the stress response of the cnidarian coral host; however, a comprehensive understanding of the molecular response to stress of coral-associated Symbiodinium, as well as differences among physiologically susceptible and tolerant types, remains largely unexplored. Here, …

Finding Them Before They Find Us: Informatics, Parasites, And Environments In Accelerating Climate Change, Daniel R. Brooks, Eric P. Hoberg, Walter A. Boeger, Scott Lyell Gardner, Kurt E. Galbreath, David Herczeg, Hugo H. Mejía-Madrid, S. Elizabeth Rácz, Altangerel Tsogtsaikhan Dursahinhan

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Parasites are agents of disease in humans, livestock, crops, and wildlife and are powerful representations of the ecological and historical context of the diseases they cause. Recognizing a nexus of professional opportunities and global public need, we gathered at the Cedar Point Biological Station of the University of Nebraska in September 2012 to formulate a cooperative and broad platform for providing essential information about the evolution, ecology, and epidemiology of parasites across host groups, parasite groups, geographical regions, and ecosystem types. A general protocol, documentation–assessment–monitoring–action (DAMA), suggests an integrated proposal to build a proactive capacity to understand, anticipate, and respond …

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 …

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 …