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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 …

Predicting Pelargonium Responses To Climate Change In A Biodiversity Hotspot Throughout South Africa, Tanisha Marie Williams

Doctoral Dissertations

Climate change is causing major shifts in species distributions, which fundamentally alters the species composition and functioning of biological communities across the globe. Projections suggest that by 2100 up to one of every six species will become extinct. Such drastic changes will have significant impacts on biodiversity patterns and ecosystem functioning. Ecologists are faced with the pressing work of trying to understand how plants will respond to changing and increasingly stressful environments. To predict the long-term effects and magnitude of species responses, it is imperative that species adaptive responses are understood across the entirety of their geographic ranges. My dissertation …

Comparison Of Otus And Asvs In 73 Bird Species From Equatorial Guinea, Darien Capunitan

Master's Theses

As scientists discover more information about the communities of bacteria that live on and inside hosts, "the microbiome", a new avenue for understanding the health of humans and animals has opened. There are many analysis pipelines for microbiome data processing, and choice of analytical tools can affect the biological results of the analysis. The current analysis climate does not point toward a single most effective protocol, which hinders comparisons across studies. An important step in microbiome data processing is the assignment of reads into groups of similar organisms. The traditional unit for grouping organisms is the species; however resolving sequences …

Patterns Of Trait And Range Size Variation In An Evolutionary Radiation: The Role Of Environmental Gradients, Timothy Eoin Moore

Doctoral Dissertations

Current threats to biodiversity are driving a research focus on understanding how environmental changes influence patterns of biodiversity at global and continental scales, deemphasizing research done at regional scales. I examined the role of environmental gradients in driving diversity patterns in the Greater Cape Floristic Region (GCFR) of South Africa, a biodiversity hotspot, renowned for its floristic diversity and high endemism levels.

The plant genus Pelargonium is centered in the winter-rainfall region of the GCFR, and varies considerably in morphology and growth form: remarkably, leaf size varies over 15000-fold across species. Pelargonium comprises 6 well-supported subclades that have diversified within …

Ecophysiology And Taxonomy Of Saccharina Latissima Forma Angustissima (Laminariales, Phaeophyceae) From The Gulf Of Maine, Usa, Simona Augyte

Doctoral Dissertations

The overarching theme of this doctoral dissertation was to resolve the taxonomic status of an endemic narrow-bladed kelp, Saccharina latissima forma angustissima (Laminariales, Phaeophyceae), which has a very restricted distribution of 8 nautical miles in the Gulf of Maine, USA. Since the kelp only grows on ledges and islands exposed to high ocean swells, it was unknown if phenotypic plasticity alone was driving its morphology or if the kelp was a distinct genotype (a population with heritable traits). I incorporated lab and fieldwork to discriminate genetic divergence of this kelp, investigated temperature and light requirements of the gametophytic and juvenile …

Population And Trophic Dynamics Of Striped Bass And Blueback Herring In The Connecticut River, Justin P. Davis

Doctoral Dissertations

Case studies of the ramifications of predator management for prey population dynamics can play a valuable role in developing ecosystem fisheries management. My dissertation focuses on the predator-prey interaction between Striped Bass (Morone saxatilis), an abundant predatory finfish, and an imperiled prey population of anadromous Blueback Herring (Alosa aestivalis). Annual returns of Blueback Herring to the Holyoke Dam on the Connecticut River in southern New England collapsed during the 1980-2000s, coincident with Striped Bass recovery. I studied the abundance and demography of both species in the Connecticut River during 2005-08, measured predation levels, and surveyed the …

The Ecological Importance Of Brachiopods Versus Bivalves In The Paleozoic: Taphonomy, Biomass, And Energy Use, Shannon (Shin-Nan) Hsieh

Master's Theses

Brachiopods have commonly been considered more important than bivalves in Paleozoic ecosystems due to their greater global diversity and greater abundance in many fossil assemblages. New sampling-standardized diversity curves verify that brachiopods were more diverse than bivalves at the global level in the Paleozoic; they declined in the Permian-Triassic extinction, largely recovered, then faded away later in the Mesozoic. However, the subordinate ecological status of bivalves within local Paleozoic ecosystems has been challenged on two fronts. First, bivalve abundance may be underestimated due to preferential dissolution of aragonitic shells. Second, bivalve contribution to ecosystem function may be underestimated by abundance …

Biodiversity Dynamics Of Forest Birds In Fragmented Landscapes: A Multidimensional Approach For Ecology And Conservation, Brian T. Klingbeil

Doctoral Dissertations

Anthropogenic modification of landscapes continues to be one of the greatest threats to biodiversity. As human populations grow and demands for natural resources and land increase, landscapes will experience intensified alteration and fragmentation, with potentially dramatic consequences for biodiversity. Consequently, development of appropriate conservation policies requires effective monitoring programs as well as an understanding of how communities are affected by human-modified landscapes. To address this, I explored how multiple dimensions of temperate forest bird biodiversity (taxonomic, functional, and phylogenetic) respond to human-modified landscapes by investigating the relative importance of habitat area, habitat configuration, and matrix heterogeneity. I evaluated relationships between …

Inorganic Carbon And Nitrogen Utilization In Mixotrophic Ciliates, Donald M. Schoener

Doctoral Dissertations

Mixotrophy is a common nutritional strategy that uses both heterotrophy and photosynthesis. Kleptoplastidic mixotrophs do not make their own plastids but acquire them from their algal prey. Before we can add mixotrophs to standard ecological models we need to understand how much each nutritional mode contributes to mixotrophic growth, and how this balance may be influenced by plastid acquisition, retention, and turnover.

In order to examine the role of captured chloroplasts in the metabolism of the oligotrich ciliate Strombidium rassoulzadegani. I evaluated the uptake and retention of chloroplasts, the ability of two different algae to supply functional chloroplasts, and …