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Full-Text Articles in Life Sciences

Modeling The Abundance And Distribution Of Terrestrial Plants Through Space And Time, Caroline Curtis Jan 2018

Modeling The Abundance And Distribution Of Terrestrial Plants Through Space And Time, Caroline Curtis

Doctoral Dissertations

Anthropogenically-driven changes threaten ecosystems and species over regional to global scales. I addressed several questions related to how species ranges will respond to these changes over large spatial and temporal extents to better understand what determines where a species occurs.

First, I modeled presence and abundance of two widespread invasive plants in the southwest U.S. under current and projected future climatic conditions, from which I inferred impact risk. These results provide more insight than presence modeling alone and highlight the possibility of increased invasion pressure in the future.

Second, I tested the assumption that expert-based climatic tolerance data will ...


Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence Jan 2017

Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence

Doctoral Dissertations

Modern and historic flood risk management involves accommodating multiple sources of sources of uncertainty and potential impacts across a broad range of interrelated sectors. Sources of uncertainty that affect planning include internal climate variability, anthropogenic changes such as land use and system performance expectations, and more recently changes in climatology that affect the resources supporting the system. Flood management systems potentially impact human settlements within and beyond the systems’ scope of planning, local weather patterns, and associated ecological systems. Federal guidelines across nations have called for greater consideration of uncertainty and impacts of water resources planning projects, but methods for ...


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


Distribution Locations Of Invasive Species (Out Of The Weeds? Reduced Plant Invasion Risk With Climate Change In The Continental United States), Bethany Bradley, Jenica Allen Jan 2016

Distribution Locations Of Invasive Species (Out Of The Weeds? Reduced Plant Invasion Risk With Climate Change In The Continental United States), Bethany Bradley, Jenica Allen

Environmental Conservation Datasets

The comma-delimited data file includes the species code (see Supplemental Online Table S2 for full species names), latitude, and longitude in decimal degrees (WGS84) for the occurence points used in model fitting. Some data use agreements prohibit the publication of coordinate data and those points have been removed.


Modeling Historical And Future Range Of Variability Scenarios In The Yuba River Watershed, Tahoe National Forest, California, Maritza Mallek Jan 2016

Modeling Historical And Future Range Of Variability Scenarios In The Yuba River Watershed, Tahoe National Forest, California, Maritza Mallek

Masters Theses

In California's northern Sierra Nevada mountains, the fire-dependent processes of forest ecosystems have been interrupted and altered by human land use and fire suppression. U.S. Forest Service policy directs land managers to plan for a future that includes multiple use and the restoration of resilient ecosystems. Planning decisions are to be informed by an analysis of the range of variability of ecological processes at multiple scales. Current climate trends in the northern Sierra are of increasing temperatures, increased precipitation, and earlier snowmelt, as well as changes to the frequency and duration of drought. These climate changes have and ...


Ecological And Management Implications Of Climate Change Induced Shifts In The Phenology Of Alewife (Alosa Pseudoharengus), Sam Stettiner, Michelle Staudinger, Adrian Jordaan, John Sheppard Jan 2016

Ecological And Management Implications Of Climate Change Induced Shifts In The Phenology Of Alewife (Alosa Pseudoharengus), Sam Stettiner, Michelle Staudinger, Adrian Jordaan, John Sheppard

Student Showcase

Climate change is causing species to shift their phenology, or the timing of recurring life events such as migration and reproduction, in variable and complex ways. This can potentially result in mismatches or asynchronies in food and habitat resources that negatively impact individual fitness, population dynamics, and ecosystem function. This project seeks to improve our understanding of shifts in the timing of seasonal migration and spawning of adult anadromous alewife, Alosa psuedoherengus in seven natal stream systems within the state of Massachusetts: Acushnet, Agawam, Herring, Jones, Nemasket, Stoney Brook, and Town Brook Rivers. Initial analyses examined if and how the ...


Integrated Modeling Of Land Use And Climate Change Impacts On Multiscale Ecosystems Of Central African Watersheds, Simon Nampindo Sep 2014

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 ...


Temperature Effects On Growth And Stress Physiology Of Brook Trout: Implications For Climate Change Impacts On An Iconic Cold-Water Fish, Joseph G. Chadwick Jr Jan 2012

Temperature Effects On Growth And Stress Physiology Of Brook Trout: Implications For Climate Change Impacts On An Iconic Cold-Water Fish, Joseph G. Chadwick Jr

Masters Theses 1911 - February 2014

Despite the threat of climate change, the physiological mechanisms by which temperature drives the distribution of species are unclear. Here we used chronic temperature exposures to determine that the upper limit for positive growth in the eastern brook trout (Salvelinus fontinalis) is 23.4 °C. Additionally, brook trout exposed to daily temperature oscillations of 8 °C, around a mean of 21 °C, exhibited growth rates that were 43 and 35% lower by length and weight respectively, than in constant 21 °C controls. Limitations in growth were associated with increases in indicators of the physiological stress response. Individuals exposed to 22 ...


Evaluating The Influence Of Disturbance And Climate On Red Spruce (Picea Rubens Sarg.) Community Dynamics At Its Southern Range Margin, Relena R. Ribbons Jan 2011

Evaluating The Influence Of Disturbance And Climate On Red Spruce (Picea Rubens Sarg.) Community Dynamics At Its Southern Range Margin, Relena R. Ribbons

Masters Theses 1911 - February 2014

Picea rubens(red spruce) populations experienced a synchronous rangewide decline in growth and vigor starting in the 1960’s, which was likely caused by climate change or environmental disturbances (e.g., acid deposition); However, it is yet unknown if populations continue to decline or have recovered. In the context of global warming, red spruce is a species of concern because it is at its southern continuous range margin in Massachusetts. This study uses tree-ring data coupled with population data from permanent plots to quantify the status of red spruce in Massachusetts. Tree cores were extracted from red spruce and used ...