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Full-Text Articles in Life Sciences

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum Dec 2017

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum

Theses and Dissertations

The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …


Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum Dec 2017

Understanding Community And Ecophysiology Of Plant Species On The Colorado Plateau, Hannah Elizabeth Yokum

Theses and Dissertations

The intensification of aridity due to anthropogenic climate change is likely to have a large impact on the growth and survival of plant species in the southwestern U.S. where species are already vulnerable to high temperatures and limited precipitation. Global climate change impacts plants through a rising temperature effect, CO2 effect, and land management. In order to forecast the impacts of global climate change, it is necessary to know the current conditions and create a baseline for future comparisons and to understand the factors and players that will affect what happens in the future. The objective of Chapter 1 is …


Adaptive Variation In Tiger Salamander Populations, Meghan Parsley Oct 2017

Adaptive Variation In Tiger Salamander Populations, Meghan Parsley

Masters Theses & Specialist Projects

Amphibians face an unknown future in a time of rapid environmental change due to global climate perturbations. Since amphibians are perceived to be indicators of ecosystem health, understanding the causes of their declines can improve our perception of threats to other species. Molecular techniques have allowed us to explore how environmental change affects genetic variation and to predict evolutionary adaptive potential of amphibian populations. The identification of populations with the greatest potential to respond to changing environmental variables may be an important conservation strategy to aid in future management efforts. I utilized targeted exon capture sequencing to identify adaptive variation …


Elevated Temperature And Co2 Concentrations Affect Carbon Flux In Two Boreal Conifers, Sasha Madhavji Sep 2017

Elevated Temperature And Co2 Concentrations Affect Carbon Flux In Two Boreal Conifers, Sasha Madhavji

Electronic Thesis and Dissertation Repository

Elevated temperatures and CO2 will alter carbon flux in two dominant boreal tree species Picea mariana (black spruce) and Larix laricina (tamarack). Trees were grown in three temperature treatments (ambient, ambient +4 °C, and ambient +8 °C) at either 400 ppm or 750 ppm CO2, to simulate climate conditions between now and the year 2100. Spruce acclimated to increasing temperature detractively; warming scenarios reduced spruce net carbon gain. Tamarack maintained comparable levels of net photosynthesis (Anet) across warming treatments and both species acclimated respiration (Rdark) with increasing growth temperature. Elevated CO2-grown …


Parasite Biodiversity Faces Extinction And Redistribution In A Changing Climate, Colin J. Carlson, Kevin R. Burgio, Eric R. Dougherty, Anna J. Phillips, Veronica M. Bueno, Christopher F. Clements, Giovanni Castaldo, Tad Dallas, Carrie A. Cizauskas, Graeme S. Cumming, Jorge Doña, Nyeema C. Harris, Roger Jovani, Sergey Mironov, Oliver C. Muellerklein, Heather C. Proctor, Wayne M. Getz Sep 2017

Parasite Biodiversity Faces Extinction And Redistribution In A Changing Climate, Colin J. Carlson, Kevin R. Burgio, Eric R. Dougherty, Anna J. Phillips, Veronica M. Bueno, Christopher F. Clements, Giovanni Castaldo, Tad Dallas, Carrie A. Cizauskas, Graeme S. Cumming, Jorge Doña, Nyeema C. Harris, Roger Jovani, Sergey Mironov, Oliver C. Muellerklein, Heather C. Proctor, Wayne M. Getz

Faculty Publications

Climate change is a well-documented driver of both wildlife extinction and disease emergence, but the negative impacts of climate change on parasite diversity are undocumented. We compiled the most comprehensive spatially explicit data set available for parasites, projected range shifts in a changing climate, and estimated extinction rates for eight major parasite clades. On the basis of 53,133 occurrences capturing the geographic ranges of 457 parasite species, conservative model projections suggest that 5 to 10% of these species are committed to extinction by 2070 from climate-driven habitat loss alone. We find no evidence that parasites with zoonotic potential have a …


The Effects Of Anthropogenic Stress On Nitrogen-Cycling Microbial Communities In Temperate And Tropical Soils, George S. Hamaoui Jr. Jul 2017

The Effects Of Anthropogenic Stress On Nitrogen-Cycling Microbial Communities In Temperate And Tropical Soils, George S. Hamaoui Jr.

Doctoral Dissertations

In this dissertation several research studies are discussed that characterize the effects of anthropogenic, or human-induced, stress on both ammonia-oxidizing and total bacterial soil microbial communities. The disturbances of land-use change in tropical, South American rainforests and artificial warming and nitrogen (N) fertilization in temperate, North American forests were investigated as these disturbances represent past and current disturbances caused by human landscape alteration and climate change. Initially, the response of soil ammonia-oxidizing microbial communities to land-use change from primary rainforest to pasture and, finally, back to secondary forest was determined. Next, these analyses of land-use change effects were expanded to …


Spatial And Temporal Variation In Mangrove Distribution (1950-2014) In Tampa, Florida Usa, Carolyn Cheatham Rhodes Jun 2017

Spatial And Temporal Variation In Mangrove Distribution (1950-2014) In Tampa, Florida Usa, Carolyn Cheatham Rhodes

USF Tampa Graduate Theses and Dissertations

I carried out an observational study of historic high resolution aerial imagery spanning six decades (1950-2014) to identify recent and historic spatial extent of mangrove forests, within the municipal boundaries of the City of Tampa, Florida USA. My objectives were to map mangrove distribution and spatial extent and any change or patterns of change discernable. I observed variable patterns of change and rates of expansion varied between sites spatially as well as within sites between time intervals. I found notable changes in mangrove extent in the Tampa from historic and modern aerial imagery for the ~64-year period between 1950 and …


Modelling Climate Suitability For Ephedra Viridis In Space And Time, Anne Thomas, Richard Gill Jun 2017

Modelling Climate Suitability For Ephedra Viridis In Space And Time, Anne Thomas, Richard Gill

Journal of Undergraduate Research

Climate change is expected to decrease soil moisture in the sensitive, water-limited ecosystems of America’s southwestern deserts, leading to shifts in plant distributions and altering ecosystem function. Studies have already documented the loss of desert grasses and the expansion of desert shrubs on the Colorado Plateau near Canyonlands National Park.i The objective of this work is to identify the climatic and biophysical factors influencing the distribution of an evergreen shrub, Ephedra viridis, and its expansion in plot-scale studies over the past 30 years.ii A gymnosperm and member of the plant division Gnetophyta, this shrub is unique because of its …


Using Maximum Entropy Species Distribution Modeling For Long-Term Conservation Planning Of Three Federally Listed Bats In North America, Mitchell L. Meyer May 2017

Using Maximum Entropy Species Distribution Modeling For Long-Term Conservation Planning Of Three Federally Listed Bats In North America, Mitchell L. Meyer

Master's Theses

We are currently in a sixth mass extinction event in which the extinction rate is higher than it has ever been. This mass extinction event is caused by human influence on the environment. Biodiversity is worth conserving because of its many uses to humans. Bats are a diverse group of mammals that humans rely on for pest control services. The gray bat, northern long-eared bat, and Indiana bat are on the Threatened and Endangered Species List and are in need of conservation. I built species distribution models using occurrence records, climate data, and Maximum entropy (MaxEnt) modeling technique. I predicted …


Growth Of Orbicella Faveolata In La Parguera, Puerto Rico, Darren B. Marshall Apr 2017

Growth Of Orbicella Faveolata In La Parguera, Puerto Rico, Darren B. Marshall

HCNSO Student Theses and Dissertations

Reef-building corals are subject to high amounts of stress, including pollution and rising sea surface temperatures due to climate change. These factors can affect the ability of corals to produce their calcium carbonate skeletons. Evaluation of the effects of climate change may be facilitated by evaluation of records of coral skeletal growth over a long period of time. The aim of this study was to evaluate skeletal growth of the coral Orbicella faveolata in La Parguera, Puerto Rico over a 32-year period. For this, 14 Orbicella faveolata core samples were collected from corals at two reefs (1.2 km apart) in …


The Alpine Vascular Plants Of Baxter State Park, Maine, Usa, Abigail J. Urban, Glen H. Mittelhauser, Matthew Dickinson, N. Rajakaruna Apr 2017

The Alpine Vascular Plants Of Baxter State Park, Maine, Usa, Abigail J. Urban, Glen H. Mittelhauser, Matthew Dickinson, N. Rajakaruna

Biological Sciences

We conducted 12 days of field surveys on five mountains over 1100 m in elevation (Katahdin, North Brother, South Brother, Mount Coe, and The Owl) in Baxter State Park (BSP), Maine during the summers of 2013–14. In addition, we examined historic manuscripts, unpublished data, and herbarium records for plant records from the five mountains. Katahdin, the largest and tallest of the five mountains, has a rich history of botanical exploration and we documented 1559 herbarium vouchers that were collected from the mountain, primarily before the mid-1900s. Combining all data sources, we documented 38 families, 87 genera, and 131 taxa of …


Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis Mar 2017

Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis

Seaver College Research And Scholarly Achievement Symposium

Between 2012-2016, southern California experienced unprecedented drought that caused dieback in Malosma laurina, a keystone species of chaparral shrub communities. Dieback was especially severe in coastal exposures of the Santa Monica Mountains, leading to whole plant mortality exceeding 50% at some sites. We hypothesized that the endophytic fungus causing the dieback, Botryosphaeria dothidea, was successful in invading the xylem tissue of M. laurina because of protracted water stress, carbon starvation, or a combination of the two. We tested these possibilities in a controlled pot experiment by comparing three treatments, each inoculated with the fungus: (1) irrigated controls (2) …


Climate Warming Can Accelerate Carbon Fluxes Without Changing Soil Carbon Stocks, Susan E. Ziegler, Ronald Benner, Sharon A. Billings, Kate A. Edwards, Michael Philben, Xinbiao Zhu, Jerome Laganière Feb 2017

Climate Warming Can Accelerate Carbon Fluxes Without Changing Soil Carbon Stocks, Susan E. Ziegler, Ronald Benner, Sharon A. Billings, Kate A. Edwards, Michael Philben, Xinbiao Zhu, Jerome Laganière

Faculty Publications

Climate warming enhances multiple ecosystem C fluxes, but the net impact of changing C fluxes on soil organic carbon (SOC) stocks over decadal to centennial time scales remains unclear. We investigated the effects of climate on C fluxes and soil C stocks using space-for-time substitution along a boreal forest climate gradient encompassing spatially replicated sites at each of three latitudes. All regions had similar SOC concentrations and stocks (5.6 to 6.7 kg C m−2). The three lowest latitude forests exhibited the highest productivity across the transect, with tree biomass:age ratios and litterfall rates 300 and 125% higher than those in …


A Comparison Of Benthic Macroinvertebrate Assemblages Between Perennial And Intermittent Headwater Streams Of The Mattole River In Northern California, Usa, Mason S. London Jan 2017

A Comparison Of Benthic Macroinvertebrate Assemblages Between Perennial And Intermittent Headwater Streams Of The Mattole River In Northern California, Usa, Mason S. London

Cal Poly Humboldt theses and projects

Intermittent streams are common throughout the world and comprise 60% or more of total river lengths in the conterminous United States. Despite their prevalence, intermittent streams are understudied, particularly first-order headwater streams, which are vital for maintaining the function, health and biotic diversity of river networks. In June 2016, I sampled five intermittent and five perennial headwater streams in the Mattole River watershed in northwestern coastal California, USA, to compare benthic macroinvertebrate (BMI) assemblages between intermittent and perennial streams. BMI samples were collected using a 500µm mesh D-net at eight randomly located riffles along a 150-m reach, and then composited, …


Differential Response Of Barrier Island Dune Grasses To Species Interactions And Burial, April Harris, Julie C. Zinnert, Donald R. Young Jan 2017

Differential Response Of Barrier Island Dune Grasses To Species Interactions And Burial, April Harris, Julie C. Zinnert, Donald R. Young

Biology Publications

Barrier islands are at the forefront of storms and sea-level rise. High disturbance regimes and sediment mobility make these systems sensitive and dynamic. Island foredunes are protective structures against storm-induced overwash that are integrally tied to dune grasses via biogeomorphic feedbacks. Shifts in dune grass dominance could influence dune morphology and susceptibility to overwash, altering island stability. In a glasshouse study, two dune grasses, Ammophila breviligulata and Uniola paniculata, were planted together and subjected to a 20 cm burial to quantify morphological and physiological responses. Burial had positive effects on both plants as indicated by increased electron transport rate and …


Efectos Del Cambio Climático En La Interacción Planta-Hormiga: Una Mini Revisión Sobre La Tolerancia Térmica, Florencio Luna Castellanos, Mariana Cuautle, Teresa Patricia Feria-Arroyo, Citlalli Castillo Guevara Jan 2017

Efectos Del Cambio Climático En La Interacción Planta-Hormiga: Una Mini Revisión Sobre La Tolerancia Térmica, Florencio Luna Castellanos, Mariana Cuautle, Teresa Patricia Feria-Arroyo, Citlalli Castillo Guevara

Biology Faculty Publications and Presentations

Sin duda alguna el clima está cambiando debido al aumento de la concentración de gases de efecto invernadero en la atmósfera provocado por la acción humana. Dichos cambios van a tener un efecto importante en algunas actividades humanas tales como la agricultura y también pueden afectar enormemente la distribución geográfica de los organismos vivos y por tanto sus interacciones. Las hormigas y las plantas tienen una larga historia evolutiva de interacción. La actividad de las hormigas y su relación con las plantas en los últimos años ha tenido un número creciente de estudios que están poniendo de relieve su papel …


Large But Uneven Reduction In Fish Size Across Species In Relation To Changing Sea Temperatures, Itai Van Rijn, Yehezkel Buba, John Delong, Moshe Kiflawi, Jonathan Belmaker Jan 2017

Large But Uneven Reduction In Fish Size Across Species In Relation To Changing Sea Temperatures, Itai Van Rijn, Yehezkel Buba, John Delong, Moshe Kiflawi, Jonathan Belmaker

School of Biological Sciences: Faculty Publications

Ectotherms often attain smaller body sizes when they develop at higher temperatures. This phenomenon, known as the temperature size rule, has important consequences for global fisheries, whereby ocean warming is predicted to result in smaller fish and reduced biomass. However, the generality of this phenomenon and the mechanisms that drive it in natural populations remain unresolved. In this study we document the maximal size of 74 fish species along a steep temperature gradient in the Mediterranean Sea and find strong support for the temperature size rule. Importantly, we additionally find that size reduction in active fish species is dramatically larger …