Ecology and Evolutionary Biology Commons^™

Threads Of Connection: An Offering To Re-Tangle Humanity And Nature With The Patterns Of Our World, Emily Shelton

Graduate Theses

In our world there are patterns of self-similarity that serve as evidence of the interconnectedness between humankind and the rest of the natural world. They are reflected in our bodies, behaviors, and environments, both natural and manmade, and can be found throughout systems at every scale, micro through macro. These organic, linear motifs branch into smaller iterations that seem to shape our existence on this planet as we gravitate towards experiences that echo these patterns. During everyday acts like shopping in a grocery store or a crowd at a concert, we unconsciously participate in self-similar collective movements as we navigate …

Ecology And Vegetation In A Passively Managed Urban Park In Worcester, Ma, Raphaella Mascia

College Honors Program

As urbanization continues to expand globally, urban parks are becoming critical habitats for human and non-human species alike. Understanding the various contexts and conditions of local parks prompts improved management and conservation efforts for such expanding urban habitats. Therefore, I assess the ecology and vegetation of a local park, Cookson Field, located in Worcester, MA, US, through a comprehensive series of vegetation surveys and examine its urban context through an examination of land-use history. I find that Cookson Field is primarily an oak (Quercus sp.) woodland with an ericaceous understory consisting mainly of blueberry (Vaccinium sp.) …

Applied Species Delimitation In Microbial Taxa And Plants, Austin C. Koontz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Species are a fundamental concept in biology, and many subdisciplines in biology utilize species in aspects of theory and in the communication of results. Given the centrality of species in biological science, it can seem surprising that there is no universal definition amongst biologists of what, strictly speaking, a species is. In fact, there are, by some estimates, over 20 different "species concepts", and this lack of a consensus is termed "the species problem". This problem has theoretical underpinnings, but has become more relevant as advances in sequencing technologies over the past two decades have allowed researchers to probe the …

Plant Evolution And Urbanization: Quantifying The Effects Of Natural Selection In Shaping Shepherd’S Purse (Capsella Bursa-Pastoris) Populations In New York City, Rebecca Panko

Dissertations

The aim of this study is to quantify the effects of natural selection in shaping Capsella bursa-pastoris populations along an urban-rural gradient in New York City.

A reciprocal transplant experiment with 168 lab-germinated C. bursa-pastoris seedlings from both urban and rural populations are grown in eight paired home and away sites distributed throughout the New York metropolitan area. Sites are visited approximately thirteen times to record plant fitness. There is evidence for local adaptation of urban populations: urban plants have longer reproductive durations and produce more seed pods in urban environments. These findings suggest that urban plants are better adapted …

Higher Temperatures Have Contrasting Effects On Different Components Of Forage Quality For Caribou In Northern Alaska, Heidi Becker

Electronic Theses and Dissertations

Rising temperatures in the Arctic may affect vegetation, which in turn can affect herbivores, such as caribou, that rely on these plants for forage. Several plant traits contribute to forage quality, including digestibility, nitrogen content, and antiherbivory secondary compounds, but the effect of temperature on these traits individually and combined is unclear. I conducted a three-component study on the effect of higher temperatures on the forage quality of graminoids, deciduous shrubs, and evergreen dwarf shrubs on the North Slope of Alaska. The components included: 1) short and long-term experimental warming, 2) natural temperature variation between south and north-facing slopes, and …

Uncovering The Drivers Of Non-Native Plant Invasions Using Ecological Data Synthesis, Marina Golivets

Graduate College Dissertations and Theses

Understanding what promotes invasiveness of species outside their native range and predicting which ecosystems and under which conditions will be invaded is an ultimate goal of the field of invasion ecology. Obtaining general answers to these questions requires synthesis of extensive yet heterogeneous empirical evidence, coupled with a solid theoretical background. In this dissertation, I sought to provide insight into the drivers of non-native plant invasions through combining and synthesizing ecological data from various sources using advanced statistical techniques. The results of this work are presented as three independent research studies.

In the first study, I aimed to understand what …

The Tensile Root Strength Of Emergent Coastal Macrophytes, Lauris Olivia Hollis

LSU Doctoral Dissertations

Spartina patens is a dominant emergent macrophyte in fresh, intermediate, and brackish marshes along the Atlantic and Gulf coasts of United States where its biomechanical properties are a key component of wetland health and resilience. Its root biomass and tensile root strength are essential for anchorage, erosion protection, and are important determinants of soil strength. Nutrients and the herbicide atrazine are suspected of negatively impacting this wetland plant and others. The objectives of this study were to: 1) ascertain the tensile root strength of five emergent coastal macrophytes in coastal estuaries, and 2) test the effects of nutrient addition, atrazine …

Whole-Canopy Net Ecosystem Exchange And Water Use Efficiency In An Intermittent-Light Environment -- Dynamic Approach, Sergey Nikolayevich Kivalov

Legacy Theses & Dissertations (2009 - 2024)

An observed 20-30% increase in forest net ecosystem exchange (NEE) on partly cloudy days is often attributed to there being more uniform canopy illumination by diffuse radiation when clouds are present. However, the sky on such days is typically populated by fair-weather cumulus clouds, bringing dynamically changing shadow-to-light conditions on the order of minutes to the forest, with radiation alternating from 1000 W m^-2 in the clear sky to less than 400 W m^-2 in under-cloud shadows. These dynamically changing conditions cannot be investigated by the conventional time-averaged eddy-covariance flux method, which requires nearly steady-state turbulent conditions over much longer …

Effects Of Manual And Mechanical Ammophila Arenaria Removal Techniques On Coastal Dune Plant Communities And Dune Morphology, Monique R. Silva Crossman

Cal Poly Humboldt theses and projects

The removal of invasive species as part of the restoration process can allow natives organisms to rebound. An ecosystem that incurs damages from invasive species is coastal sand dunes, which are dynamic systems. Some coastal sand dunes on the west coast of the United States have been invaded by Ammophila arenaria. The invasive grass, A. arenaria, is thought to alter and stabilize foredune morphology and reduce populations of native species. The objectives of my research are to examine the effects that manual and mechanical A. arenaria removal techniques have on coastal sand dune morphology and vegetative cover over time. …

Amphibian And Plant Communities Of Natural And Constructed Upland-Embedded Wetlands In The Daniel Boone National Forest, Rachel Fedders

Online Theses and Dissertations

Wetlands fulfill many vital ecological functions, including providing habitat for amphibians and plants. Some wetlands, known as upland-embedded wetlands (UEWs), are depressional wetlands surrounded completely by upland habitat. This wetland type has been constructed in many areas for conservation and mitigation purposes, but constructed UEWs often do not function equivalently to natural wetlands, and often have different physical and chemical characteristics. In the Daniel Boone National Forest (DBNF), numerous UEWs have been constructed on ridge-tops to benefit game and bat species. Previous studies have shown that many of these constructed wetlands have permanent hydroperiods and different amphibian communities than co-occurring …

Varying Water Stress In Mimulus Ringens, Sara Stiles

Williams Honors College, Honors Research Projects

A wetland plant’s ability to tolerate flooding is important to determining where that plant can grow. Previous studies have shown the optimal flood tolerance of Mimulus ringens is between -2cm and -6cm (Fraser & Karnezis, 2005). This experiment expands on these previous experiments by testing variation in water levels instead of maintaining the water levels at one height throughout the experiment. The hypothesis of the experiment is that Mimulus ringens that have variation in water levels will show signs of better growth than plants with a constant water level. Contrary to predictions, the results showed the final height, number of …

Environmental Factors, Not Plants, Contribute To Functional Diversity Of Soil Bacteria In The Dunes Of Lake Michigan., Andrea Stark Howes

Electronic Theses and Dissertations

Soil bacteria play important roles in nutrient cycling and other ecosystem functions, and many biotic and abiotic factors can influence bacterial functional diversity. The goal of this field study was to examine differences among bacterial communities in sand dunes of Lake Michigan. I used Biolog Ecoplates™ to compare bacteria functional diversity associated with four different plant species: the native dune-building grass Ammophila breviligulata, invasive species Leymus arenarius and Gypsophila paniculata, and native legume Lathyrus japonicus across 13 sites in Michigan, representing a gradient in abiotic factors such as precipitation and temperature. I found no differences in bacterial function associated with …

Grazing And The Coupling Of Vascular Plant And Soil Microbial Diversity In Agricultural Landscapes Of Eastern New York, Caroline Belle Girard-Cartier

Legacy Theses & Dissertations (2009 - 2024)

ABSTRACT

Individual Variation In Plant Traits Drives Species Interactions, Ecosystem Functioning, And Responses To Global Change, Quentin Daniel Read

Doctoral Dissertations

Ecologists have long sought to understand the processes that lead to the riotous diversity in communities of organisms that inhabit disparate climates and landscapes. Such a diversity of traits leads to a diversity of interactions among species in natural communities, which in turn generates a diversity of potential responses to ongoing global change. In this dissertation, I do three things: I explore the forces that structure plant communities and the ecosystem functions that they mediate, I describe patterns of variation among communities, species, and individual organisms across environmental contexts, and I disentangle the direct effects of global change from the …

More Than Movement – Ant Seed Dispersal Inhibits Phytopathogenic Fungi, Charlene H. Gray

Biology Theses

Seed dispersal by ants is a cosmopolitan mutualism involving thousands of plant species. Ants gain a food reward (elaiosomes) from the plant seed, and ant-mediated plants gain several presumed benefits, including dispersal away from parent plants and placement in 'safe site' microhabitat. Higher plant germination and survival in ant nest soils has been attributed to higher levels of nutrients, aeration, and soil moisture than surrounding soils, but evidence in support of these benefits is inconsistent. Ants secrete anti-microbial compounds that inhibit microbial pathogens. I explore the possibility that ants transfer anti-microbial properties to the soil they inhabit, and there is …

Plant-Soil Relations On Gypsum And Non-Gypsum Soils Of The Chihuahuan Desert, Clare Muller

Senior Honors Projects

No abstract provided.

Habitat Assessment Of Two Narrowly Endemic Plant Species, Ozark Spiderwort (Tradescantia Ozarkana) E. S. Anderson And Woods. And Newton's Larkspur (Delphinium Newtonianum) D. M. Moore, Autumn Lynn Coffey Olsen

Graduate Theses and Dissertations

The threat of biodiversity loss is upon us with the onset of climate change and our ever-demanding needs of the Earth's resources for a rapidly growing human population. Species highly vulnerable to loss are those limited in abundance and distribution, or those with reduced genetic diversity. Efforts to actively conserve a sensitive species require effectual data on the probable causes of their vulnerability. Two species of concern, Delphinium newtonianum and Tradescantia ozarkana, are globally rare endemic vascular plant species found only in the Interior Highlands of North America. In an attempt to understand the causes for their endemism, habitat …

The Vascular Flora Of Greater San Quintín, Baja California, Mexico, Sula E. Vanderplank

CGU Theses & Dissertations

The plants of San Quintín (Baja California, Mexico) were documented through intensive fieldwork and the collection of herbarium specimens to create a checklist of species. This region is home to a diverse flora with high levels of local endemism and many rare plants. The flora documented in this study was compared to historical records from the region and shows the impact of agriculture and urbanization on the plants, including several extirpated species. A study of the perennial vegetation using a 1 km grid provides species distribution data for 140 native species, which were assessed to highlight areas of significant species …

Vegetation Analysis: A Graphical Analysis Of Plant Succession In Desert Communities Affected By Fire, Jeff Lantow

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Mojave Desert is affected by fire every year. With each fire comes the removal of old growth and, in its place, new growth – consisting primarily of those species which thrive in disturbed areas. The focus of my research is to look at plant communities that have been disturbed by fire, and examine the successional pathway of these disturbed environments. The seven environments I analyzed were burned within the last twenty years and are found in the Coleogyne ramosissima ecotone throughout the Spring Mountain range near Las Vegas, Nevada. The data was collected with randomly chosen circle plots in …

Utilization Of Spatially Distributed Soil Resources By Several Species Common To The Great Basin, Sarah Duke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heterogeneous spatial and temporal distributions of soil resources important to plant growth have been documented in the sagebrush steppe ecosystem. There can exist as much variability in soil resources within the root zone of individual plants as exists across an entire field. The objective of this dissertation research was to evaluate how plants respond to, utilize and influence the spatial heterogeneity of soil resources. The three specific sets of questions addressed are outlined in the three main chapters of this dissertation.

My first study addressed how the number and concentration of phosphorus (P) patches in the root zone of an …

Utilization Of Crested Wheatgrass Plants By Cattle Under Several Grazing Regimes, Patricia Selann Johnson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Patterns of grazing on individual crested wheatgrass plants were studied using scale maps of plant basal outlines within randomly located plots. The occurrence and extent (part of plant grazed, stubble height) of grazing on each plant was recorded on the maps at two and three day intervals throughout a grazing treatment. Allometric equations for estimating phytomass from plant photosynthetic volume were generated using nonlinear regression analysis. Equations were specific to year. The percent weight remaining in the stubble of a grazed plant was estimated using a second-order polynomial equation relating cumulative percent plant height to cumulative percent plant weight. A …

Belowground Resource Exploitation In Semiarid Plants: A Comparative Study Using Two Tussock Grasses That Differ In Competitive Ability, David M. Eissenstat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The relative competitive abilities of Agropyron desertorum and Agropyron spicatum were compared using Artemisia tridentata transplants as indicator plants. Although these two tussock grasses have similar shoot growth forms and shoot physiological characteristics, they have substantial differences in their competitive abilities. Artemisia had lower survival, growth, reproduction, and water potential when transplanted into neighborhoods of A. desertorum than in neighborhoods of A. spicatum.

Plant attributes associated with the differences in competitive ability were explored. Agropyron desertorum and A. spicatum have remarkably similar potential growth rates at warm soil temperatures. In a prolonged cold soil temperature treatment in the greenhouse, …

The Effect Of Four Mine Spoil Treatments On The Seedling Water Relations Of Two Plant Species, Lorraine K. Van Kekerix

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Surface mines in mountainous areas cause environmental deterioration at lower elevations in the watershed. The most successful long term solution to the downstream problem is revegetation. However, mine spoils are low in essential plant nutrients, have low water holding capacity, and are often acidic. These factors limit plant colonization. Plants must also be adapted to the environmental conditions of high elevations.

At the McLaren Mine, }1ontana, at 2800 m, it was observed that seedlings on revegetation plots were desiccated, indicating possible water deficits. Field and growth chamber studies were carried out to determine the effects of some spoil ameliorating treatments …

Annotated Checklist Of The Vascular Plants Of Washington County, Utah, Susan Elizabeth Meyer

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis is comprised of two parts, the annotated checklist of plants and the explanatory text which precedes it.

The checklist includes entries for the 1,207 vascular plant species known to occur in Washington county. each entry consists of species name, floristic component classification, community type occurrence, range termination information, specimen citations, and in some cases notes and relevant synonymy.

The explanatory text includes a discussion of the methods used in the preparation of the checklist, a description of the study area, a conspectus of botanical research in the area, and a summary of the systematic and phytogeographic affiliations of …

Feeding Behavior Of Pen Reared Mule Deer Under Winter Range Conditions, Michael A. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the feeding responses of mule deer to a system of spring livestock grazing. The specific purposes were 1) to determine botanical composition of diets selected by mule deer on a winter range subjected to previous spring grazing by sheep compared to one with no sheep grazing and 2) to develop a basis for predicting selection of individual plants by deer, based on physical characteristics of the plants and the species and physical proximity of associated plants.

The study was conducted within the framework of a completely randomized experimental design with two treatments. Variables controlled for each unit …