Ecology and Evolutionary Biology Commons^™

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald Thomas Garrett

Theses and Dissertations

Though the rate of deforestation has slowed in recent years, it remains a primary cause of land cover change within forest ecosystems. The Lower Rio Grande Valley, Texas (LRGV) has lost nearly 95% of its native thornforest since the early 1900’s due to agricultural and urban expansion. The focus of this study is to assess the current vegetative state of restored thornforest sites located in the eastern LRGV and to evaluate the use of cover crops during replanting of native seedlings. Our assessment of restored thornforest sites revealed actively restored sites demonstrated higher overall averages of richness, abundance, and diversity …

Patterns, Mechanisms, And Characterization Of Carbon Cycling Stability Following Partial Forest Disturbance, Kayla C. Mathes

Theses and Dissertations

Among the most essential questions in the era of climate change is how the forest carbon (C) cycle will respond to an increase in the extent of biotic disturbances from insects and pathogens. While research has focused on stand-replacing disturbance regimes, less is known about C cycling stability following partial disturbances that produce gradients of disturbance severity. Belowground C cycling responses to disturbance are especially poorly understood, even though temperate forest soils contain up to 50% of total ecosystem C and soil respiration (R_s) accounts for more than half of temperate forest C loss. Interpreting trends and mechanisms …

Animal Husbandry In The 21st Century: Application Of Ecological Theory And Precision Technology To Inform Understanding Of Modern Grazing Systems, Ira Lloyd Parsons

Theses and Dissertations

Ruminant animals comprise the greatest proportion of herbivores around the world, provide essential ecosystem services and human consumable protein by consuming grass and human inedible dietary fiber. Herbivory pressure alters plant communities and species diversity, effectively making grazing animals ecosystem engineers in dynamic ecosystems. Development of advanced computer processing power coupled with biometric and ecosystem sensors may be employed in the internet of things framework to create an integrated information system designed to inform understanding of grazing system function and animal energy balance. Towards this end, I utilized Bos indicus / Bos taurus crossbred steers (n = 20) across two …

Quantifying Contributions Of Climate, Geography, And Gene Flow To Divergence: A Case Study For Three North American Pines, Constance E. Bolte

Theses and Dissertations

Long-lived species of trees, especially conifers, often display weak patterns of reproductive isolation, but clear patterns of local adaptation and phenotypic divergence. Discovering the evolutionary history of these patterns is paramount to a generalized understanding of speciation and the processes that confer population persistence versus those that compromise adaptive potential under rapidly changing environments. Forest trees have long generation times and low migratory potential making them especially vulnerable to population fragmentation and reductions of genetic diversity due to insufficient tracking of niche optima and adaptational lags. Within clades of the genus Pinus, evolutionary histories appear to be riddled with hybridization …

Some (Im)Material Girls, Living In (Im)Material Worlds, With Seeds, Stars, And Shit, Matthew Weiderspon

Theses and Dissertations

This writing situates material and gestural vocabularies cultivated in my artwork in relation to my lived experience; primarily my rural upbringing in Colorado. Scattered floor dispersals, calling sounds, and bodily movements desire reconsiderations of hope in precarity through a disorientation of place, association, scale, and language.

Autumn Tree Phenology In Northern Wisconsin: Humans Versus Photographs, Trevor Iglinski

Theses and Dissertations

Ecosystem primary productivity halts when plants go dormant, and so the timing of dormancy as it relates to autumn phenology has been a focus of much interdisciplinary research. While monitoring plant phenology has its roots in directly observing specimens, digital sensors along with modern methods have also become a mainstay in phenology. Results from different methods often vary, so there is still a need to better understand how digital cameras record autumn phenology, especially in comparison with ground-based observations (Keenan et al. 2014). This study compared autumn phenology derived from direct ground observations with upward-facing fisheye photography, in the context …

The Mechanisms And Consequences Of Shrub Encroachment On The Virginia Barrier Islands, Lauren K. Wood

Theses and Dissertations

Shrub encroachment is a global phenomenon driven by direct and indirect anthropogenic influence which alters plant communities and ecosystem function. Many studies have investigated drivers and consequences of woody plant establishment, but mesic landscapes are underrepresented in the literature. My objective was to assess the mechanisms of Morella cerifera encroachment into coastal mesic grassland, the potential for self-reinforcement, and consequences on community composition, nutrients, and landscape productivity. I studied temperature and water microclimate modification by Morella cerifera presence and removal to understand ecosystem engineering and community composition changes. Additionally, I examined the influence of shrubs on surrounding grassland species traits …

Interspecific Gene Flow Potentiates Adaptive Evolution In A Hybrid Zone Formed Between Pinus Strobiformis And Pinus Flexilis, Mitra Menon

Theses and Dissertations

Species range margins are often characterised by high degrees of habitat fragmentation resulting in low genetic diversity and higher gene flow from populations at the core of the species range. Interspecific gene flow from a closely related species with abutting range margins can increase standing genetic diversity and generate novel allelic combinations thereby alleviating limits to adaptive evolution in range margin populations. Hybridization driven interspecific gene flow has played a key role in the demographic history of several conifer due to their life history characteristics such as weak crossability barriers and long generation times. Nevertheless, demonstrating whether introgression is adaptive …

Plant-Pollinator Associations In An Eastern Serpentine Savannah And The Effects Of Overbrowsing, Allyson Richins

Theses and Dissertations

Chapter 1: Native plant response to deer overbrowsing in a serpentine savannah

Plants are particularly vulnerable to physical disturbance in low productivity areas, due to a high cost of replacing lost plant tissue. In the eastern United States, serpentine grasslands are fragmented ecosystems with high concentrations of rare endemic plant species, low concentrations of soil nutrients, and uncontrolled deer overpopulation. This study assessed functional responses of native angiosperms in a rare eastern serpentine savannah to selective deer browsing. Plant count, flower count, floral area, vegetative area, and plant height of 10 serpentine plant species were compared inside and outside of …

Stimulated Growth Response To Sand Burial Of A Coastal Shrub, D. Nicole Keller

Theses and Dissertations

Drivers of vegetation zonation on barrier islands are complex and interconnected. Sand burial is a strong driver in dynamic coastal systems, especially in the foredune community. However, it is not well understood how burial impacts the interdunal swales communities and it is especially difficult to separate the effects of burial from salinity. Climate change is altering the frequency of overwash events as well as expanding the range of the native shrub, Morella cerifera, on the Virginia barrier islands. To accurately forecast island response to climate change it is important to understand how the shrub responds to sand burial. Juvenile …

Belowground Characteristics Of Dominant Coastal Dune Grasses And Potential Community-Level Effects On Coastal Erosion, Shannon L. Walker

Theses and Dissertations

Natural dunes arise out of complex relationships between ecological, hydrological, and geological processes and are important for reducing erosion along coastlines. Aboveground structures of coastal dune grasses are known to impact erosional dynamics, and recent studies have shown that belowground structures—such as roots, rhizomes, and belowground stems— may be important in erosional resistance. My objectives were to 1) characterize above- and belowground characteristics of prominent dune grasses and 2) combine these data with functional group abundances and distribution to evaluate community effects on two adjacent locations of distinctive morphology and erosional characteristics and their response to storm disturbance. Whole plant …

Chamaecrista Fasciculata In Tallgrass And Sand Prairies: The Potential For Differential Responses, Robert W. Philips

Theses and Dissertations

Successful establishment of a diversity of native species has become an important goal for restoration site managers to achieve, however as seed sources for a species may occur in habitats with different abiotic and biotic characteristics. Consequently, seeds from different sources may vary in their success in a restoration. Chamaecrista fasciculata, a native prairie species, occurs in two divergent prairie types - tallgrass and sand prairies. Tallgrass prairies have a moist soil with dense vegetation; in contrast, sand prairies have a well-drained sandy soil with sparse vegetation. I propose differential selection acting on populations in these prairie types would affect …

Natural And Anthropogenic Drivers Of Tree Evolutionary Dynamics, Brandon M. Lind

Theses and Dissertations

Species of trees inhabit diverse and heterogeneous environments, and often play important ecological roles in such communities. As a result of their vast ecological breadth, trees have become adapted to various environmental pressures. In this dissertation I examine various environmental factors that drive evolutionary dynamics in threePinusspecies in California and Nevada, USA. In chapter two, I assess the role of management influence of thinning, fire, and their interaction on fine-scale gene flow within fire-suppressed populations of Pinus lambertiana, a historically dominant and ecologically important member of mixed-conifer forests of the Sierra Nevada, California. Here, I find evidence …

Floral Symmetry Genes Elucidate The Development And Evolution Of Oil-Bee Pollinated Flowers Of Malpighiaceae And Krameriaceae, Farahnoz N. Khojayori

Theses and Dissertations

Specialization on insect and animal pollinators is thought to be the driving force for the evolution of floral traits. Specifically in the New World (NW), the oil-bee pollination syndrome has led to the convergence of floral characters in two distantly related families of core eudicots, Malpighiaceae and Krameriaceae. Both families display a flag-like structure that establishes a zygomorphic flower and floral oil rewards in epithelial elaiophores. These traits work concomitantly to attract and reward female oil-bees that help fertilize these flowers and in return receive oils. The underlying genetics of floral zygomorphy were studied in several clades of core eudicots, …

Short-Term Effects Of Nutrients On A Barrier Island Grassland Community, Ashley Moulton

Theses and Dissertations

Increased nutrient availability globally has the potential to affect community functional composition of plants in nutrient limited environments, such as coastal grassland systems. Stability of these systems are threatened worldwide by urbanization, as well as effects of sea level rise and increased frequency and intensity of storms, and atmospheric N deposition, associated with climate change. Annual net primary productivity (ANPP), species composition, and functional traits (community weighted specific leaf area (CWSLA), leaf area index (LAI), growth form and photosynthetic pathway) were measured across four treatments to assess multiple resource limitation of nitrogen (N) and phosphorus (P) and functional community response …

Consequences Of Loss Of An Abundant Pollinator: An Experimental Study, Allysa Hallett

Theses and Dissertations

Pollinator populations are declining worldwide, and this may lower the quantity and quality of pollination services. Since pollinators often compete for floral resources, loss of an abundant pollinator species may release others from competition and potentially alter floral visitation rates. We explored how the removal of a frequent pollinator, bumble bees, influenced pollination success of whorled milkweed (Asclepias verticillata). In three small and three large populations we quantified pollinator visitation rates and pollination success for control plots and for plots where bumble bees were experimentally excluded. We found that exclusion of bumble bees did not reduce A. verticillata pollination success. …

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

The Curiosity Of Con, Petrified Breath, And An Accident Known As Blue., Steven Randall

Theses and Dissertations

My thesis installation emerged from an interest in visualizing breath. The resulting work came to exist at the intersection between art, biology, and performance.

The unicorn tapestries were used as a generative point of departure to explore the preservation and transformation of images through time, by time, and with time. Reproductions of the six tapestries were each etched into paper and then submerged into solutions of Phenol Red dye, Ferric Ferrocyanide (also known as Prussian Blue), and various forms of sodium chloride. Exhaled breath was used to encrust these images of the tapestries into physical objects which gradually crystallized and …

Factors Constraining The Reproductive Output Of Baptisia Alba Macrophylla, Ashley Morgan Hembrough

Theses and Dissertations

Baptisia alba macrophylla, a native, herbaceous perennial legume, produces inflorescences with a large number of flowers, yet matures relatively few fruits. We hypothesized that the number of seeds matured by B. alba macrophylla is maximized based on resource availability at each stage of development, but this optimal number is further compromised by extrinsic factors including pollen limitation and pre-dispersal seed predation by the weevils Apion rostrum and Tychius sordidus. To test this hypothesis, we conducted a field experiment at two sites: (i) the John English Prairie, located in Hudson, IL, and also (ii) the Sugar Grove Nature Center and Funks …

Plant Dioecy, Ecology, Evolution And Sex Reversal, D. Carl Freeman

Theses and Dissertations

The distribution of dioecious species among forty-four plant communities of western United States was examined. The dioecious habit is most prevalent in harsh environments. In many communities, over 20 percent of the species and 40 percent of the individuals are dioecious. Dioecy is most common among woody species which are pollinated by wind. It is concluded that inbreeding depression alone is insufficient to account for all known facts concerning dioecy. Disruptive selection acting upon differential success of gametes produced on sites of differing quality appears to have played a major role in producing separate sexed individuals. Dioecious species reported to …

A Paleocene Flora From The Fort Union Formation Near Baggs, Carbon County, Wyoming, John L. Roth

Theses and Dissertations

A well-preserved Paleocene flora of 39 species from the Fort Union Formation near Baggs, Carbon County, Wyoming has been studied. This is the first study of the plant megafossils in this area. The most abundant species collected are: Carya antiquorum Platanus nobilis, Cercidiphyllum arcticum and Platanus raynoldsi. Together they represent 74% of the flora. The flora has been dated as Upper Middle Torrejonian. This report is also the first paleoecological study of any North American Paleocene flora. Two methods were used to determine the paleoclimatic conditions of the flora. The first was an analysis of leaf margin characteristics, comparing them …

Diatom Phytoplankton And Periphyton Studies Of The Headwaters Of Henrys Fork Of The Snake River, Island Park, Idaho, Richard L. Clark

Theses and Dissertations

An ecological baseline study of the diatom flora was conducted on the headwaters of Henrys Fork of the Snake River, Idaho. The diatom flora of this spring fed drainage basin consisted of both phytoplankton and periphyton. Thirty-nine genera, two hundred forty-four species, eighty-two additional varieties, and seven additional forms were identified from these waters. Species of Melosira, Stephanodiscus, Fragilaria, Synedra, and Asterionella were found in the plankton of Henrys Lake and Island Park Reservoir. Diatoma, Fragilaria, Synedra, Eunotia, Achnanthes, Navicula, Pinnularia, Gomphonema, Cymbella, Nitzschia, and Surirella were the important genera present in the periphyton.

A Taxonomic And Ecologic Study Of The Riverbottom Forest On St. Mary River, Lee Creek And Belly River In Southwest Alberta, Canada, Robert Keith Shaw

Theses and Dissertations

The riverbottom forest community of St. Mary River, Lee Creek and Belly River in southwest Alberta, Canada is a unique ecological entity characterized by poplar species having their major Alberta distribution along these streams. Stands in the community are dominated by three tree species, six shrub species and nine herb species. Establishment of the community is dependent on climate and substrate; destruction is the result of progressive lateral stream-flow erosion. Soils are sandy loams above gravel, with pH values of 7.7 to 8.0 and soluble salt concentration of 176 to 458 parts per million. Trees in mature stands averaged 23.0 …

Community Characteristics Of Six Burned Aspen-Conifer Sites And Their Related Animal Use /|Clarry H. Kleinman, Larry H. Kleinman

Theses and Dissertations

Six forest areas destroyed by fire representing different seral stages of aspen development and conifer invasion were studied to determine successional dynamics and the related livestock and big game use. Factors measured were: (a) age, basal area, density and frequency of aspen and conifer trees; (b) density and frequency of under-story species; (c) forage production for forbs, grasses, and browse, and (d) animal-days use for deer, cattle and sheep. Aspen appeared in the community the spring following the fire and conifers appeared fifteen to twenty years later. Conifers had begun to dominate aspen on an eighty-two year old stand. The …

A Flora From The Dakota Sandstone Formation Near Westwater, Grand County, Utah, Samuel R. Rushforth

Theses and Dissertations

A cretaceous (Cenomanian) flora from the Dakota Sandstone Formation near Westwater, Grand County, Utah contains an admixture of ferns and angiosperms. The ferns of this flora are representative of an older Jurassic-Wealden vegetational type, whereas the angiosperms are typical of the modern vegetational type. Species of Gleichenia and Matonidium and Astralopteris coloradica represent the dominant forms in this flora. The Westwater flora contains fourteen genera including nineteen species and one variety. New species described from this flora include Asplenium dakotensis, Coniopteris westwaterensis and Ilex serrata.

Notes On The Fern Family Matoniaceae From The Western United States, Samuel R. Rushforth

Theses and Dissertations

A Cretaceous fern flora haas been recently discovered near Westwater, Grand County, Utah. Among specimens collected from Westwater are many forms related to extant members of the fern family Matoniaceae. This family was widely distributed geographically throughout most of the Mesozoic Era, and matoniaceous ferns have been collected from several fossil localities in the United States. The Matoniaceae was especially important in the United States during Lower Cretaceous times. Five species, Matonidium brownii Rushforth, Matonidium lanceopennis Rushforth, Matonidium galleyi (Miner) Rushforth, Matonidium americanum Berry em. Rushforth, and Matonidium sp., and one variety, Matonidium brownii var. extenda Rushforth, are considered in …

An Ecological Study Of The Algae And Mosses Of Cascade Springs, Wasatch County, Utah, Deanna Lynn Mccoard

Theses and Dissertations

An ecological study was conducted at Cascade Springs, Wasatch county, Utah from August 1965, to June 1967. The algae and aquatic moss species were determined and ecological information about these organisms was obtained. Physical data were also collected: bicarbonates, carbonates, free carbon dioxide, hydroxides, oxygen, pH, and temperature. The physical environment of the water was found to be very constant. Tests taken at the different study sites were consistently similar, not only during each day, but all year around. No great variation of any kind was found in the water. In contrast to the water environment, the topography of the …

Perennial Atriplex Of Utah And The Northern Deserts, Craig A. Hanson

Theses and Dissertations

Atriplex is a genus in the Chenopodiaceae, the perennial members of which are ecologically important in western North America. Seventeen species and one subspecies of perennial Atriplex occur in Utah and the northern deserts. Three of these species and the subspecies were described by the writer in a recent publication as a result of extensive field work leading to this study. These are A. welshii, A. navajoensis, A. bonnevillensis, and A. cuneata ssp. introgressa. This study is an investigation of the systematics and phytogeography of the perennial Atriplex in Utah and the northern deserts, with emphasis on the A. gardneri …

An Ecological Study Of An Exclosure In The Mountain Brush Vegetation Of The Wasatch Mountains, Utah, Elray S. Nixon

Theses and Dissertations

This is a comparative study of the vegetation and soils of an exclosure in the mountain brush vegetation of the Wasatch Mountains, Utah. The exclosure was fenced and initially analyzed during the summers of 1949-1950. The study area is located in Pole Canyon in the Uinta National Forest, a few miles northeast of Provo, Utah. The dominant woody species of the vegetation in the exclosure are big toothed maple (Acer grandidentatum) and Gambel oak (Quercus gambelii). After settlement of the area in and around Provo, Pole Canyon became overgrazed by livestock. Since 1949 the area has been protected from grazing. …

The Succession Of Vegetation On A Southern Utah Sand Dune, Elias S. Castle

Theses and Dissertations

The sand dunes lying ten miles northwest of Kanab in Kane County, Utah, support a sparse plant cover with four species dominating the vegetation: Psoralea stenostachys, Sophora stenophylla, Oryzopsis hymenoides, and Wyethia scabra var. attenuata. Of these Psoralea and Wyethia are endemic to the dunes or to a limited area which includes the dunes. The pineer species gain a start in the valleys between dunes and occupy the area only until sand covers them or until sand is blown away from their roots. Stabilization of the soils is not permanently in the interdune valleys and the dunes continue to wander. …