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Effects Of Water Table Depth And Edaphic Characteristics On Plant Diversity In A Southern Mississippi Pitcher Plant Bog, Patrick Kirby

Master's Theses

This study examined the effects that water table depth and soil characteristics have on plant species richness and species composition within pitcher plant bogs across seasons. Eight piezometers were installed at random distances to monitor long-term water table depth and pressure fluctuations along a ~710-meter line transect traversing upland and bog habitats. Vegetation sampling quadrats (n=128) were set up near each piezometer. Cover data and water table depths were collected in spring and late summer. Soil samples collected from each treatment group were used to obtain soil texture and nutrient data. The summer collection period yielded a total gdiversity of …

A Description Of Lichen Community Structure And The Impacts Of Spruce Beetle Disturbance In Northwestern Colorado, Anna Freundlich

Master's Theses

Spruce beetle disturbance has affected millions of acres of forest throughout North America and Europe, but thus far little research has investigated how this disturbance influences lichen communities. To address this problem, we studied lichen communities and habitat characteristics within 44 plots across a chronosequence of spruce beetle damage spanning 1996–2017 in northwestern Colorado. We found 82 species of lichens, few habitat differences among spruce beetle disturbance classes, and only the most recently affected plots (2012–2017) had significantly different lichen community structure relative to remaining areas. Two primary gradients explained the majority of variation of lichen community structure within our …

The Energetic Cost Of Anthropogenic Disturbance On The Southern Sea Otter (Enhydra Lutris Nereis), Heather Elizabeth Barrett

Master's Theses

With increased human populations and tourism in coastal areas, there is greater potential for disturbance of marine wildlife. Having high metabolic rates, sea otters (Enhydra lutris nereis) are at risk of increased energetic costs due to disturbance. To investigate these effects, sea otter activity in response to potential disturbance stimuli was recorded over three years, at three California locations: Monterey, Moss Landing, and Morro Bay. A hidden Markov Model was developed to examine how activity varies as a function of location, group size, pup to adult ratio, kelp canopy, and occurrence of and proximity to disturbance stimuli. Results were combined …

Dynamics And Ecological Implications Of The Ulva-Zostera Ecotone In Elkhorn Slough, California, María Vila Duplá

Master's Theses

Ecotones are transitional areas between adjacent ecological communities that have unique ecological qualities defined by space and time scales, and by the interactions between adjacent systems. Ecotones play an essential role in supporting biologically diverse communities, and are sensitive indicators of global change. An Ulva-Zostera ecotone extends along the northern shore of Seal Bend in Elkhorn Slough, an estuary located in central California. Although previous studies have mentioned the presence of the Ulva-Zostera ecotone, this was the first study to focus on understanding its driving factors, spatiotemporal dynamics, and overall ecological implications. A combination of habitat monitoring, water quality assessments, …

Floral Preformation In The Warming Boreal Forest: The Effects Of Temperature On The Development Of Vaccinium Vitis-Idaea, Eileen Schaub

Master's Theses

The boreal forest is experiencing climate change at twice the rate of other regions. Although changes in flowering phenology are a known consequence of warming temperatures, much is unknown about the effects of temperature anomalies on floral development. Boreal angiosperms preform flowers a year or more in advance and are consequently subject to varied environmental conditions across that time. My thesis examines the effects of temperature on floral development in order to understand how boreal taxa will respond to climate change.

Collection of Vaccinium vitis-idaeafrom natural populations in Fairbanks, Alaska was carried out over the growing seasons of 2017 …

Examining Genetic And Ecological Differentiation Of An Endemic Plant Species Found Across The Hawaiian Archipelago, Psychotria Mariniana, Tiffany L. Kho

Master's Theses

Speciation is a fundamental evolutionary process that remains poorly understood. Speciation ultimately begins with population divergence, so we can elucidate the complexities of speciation by first understanding the process and drivers of population divergence. To conduct population-level analyses, ecologists and evolutionary biologists have turned to island systems, primarily for their geographic orientation and high endemism. The Hawaiian archipelago is home to over 8,700 endemic species making it a great natural laboratory to study species diversification at the population level. The Hawaiian Psychotria (kōpiko, or wild coffee) make up 11 of these species and have been used to understand colonization and …