Botany Commons^™

Patterns Of Fire History And Vegetation Changes In The Last 5000 Years: A Paleoecological Study Of Iquitos, Annabel Zwarts

Theses and Dissertations

The vegetation of the Amazonian rainforest is hypothesized to have been shaped by pre-Columbian activities, such as burning and palm management to various extents. Management of palms is hypothesized to have caused some of the most useful species to become hyperdominant in Amazonia. This study investigated the extent to which human activities over the past 5000 years affected palm abundances in mature lowland rainforests near Iquitos, Peru. I used phytoliths and charcoal from soil cores to determine the history of local floras, and modern palm surveys to compare modern phytolith occurrence with modern vegetation. Because pre-Columbian activity clustered along the …

Chromosome Evolution Model Reveals Hidden Variation In Karyotype-Driven Speciation In Ferns, Thomas Buchloh

All Theses

Because karyotype change commonly generates reproductive isolation between diverging species, rapid karyotype evolution, like that seen in plants, may increase the total rate of diversification. However, few studies have investigated this predicted relationship. Tests of this prediction have identified a positive correlation between the rate of karyotype change (specifically whole genome duplications) and diversification, but tests have been restricted to relatively small and young clades. Fortunately, novel macroevolutionary models have recently become available to investigate patterns of karyotype evolution in large phylogenies, providing new opportunity to investigate variation in karyotype driven diversification. Ferns are one of the most karyotype rich …

Life After Death: Investigating The Resistance And Recovery Of Fungal Communities To Foundation Tree Mortality, Jessie F. Marlenee

Biology ETDs

Tree mortality can have cascading effects on the composition and resilience of interacting fungal communities. Yet, little is known about the impact tree mortality, distinct from abiotic drivers (i.e., drought), has on these communities. This dissertation focuses on the resilience of fungal communities to experimental tree mortality in a piñon-juniper woodland. In chapter one, I found that piñon mortality reduced piñon fine root biomass and piñon mycorrhizal fungal diversity, whereas juniper mycorrhizal fungi were unaffected by juniper mortality. In chapter two, I revealed that piñon mortality altered the composition and spatial structure of mycorrhizal and saprotrophic fungi in the soil, …

Assessing Understory Along The Elk River (Hikshari') In Headwaters Forest Reserve, Humboldt County, California, Julie R. Meyers, Aliyah M. Ingram, Caleb N. Larkin, Joshua L. Carpenter

Environmental Science & Management Senior Capstones

Northern California’s extensive logging history and lack of forest management has altered old-growth coast redwood (Sequoia sempervirens) forests, leaving dense, homogenous second and third-growth forest stands. This has led to the use of modern restoration techniques such as variable density thinning (VDT) which aims to rehabilitate old-growth forest conditions by improving stand heterogeneity and light availability for understory species. Our study was done in Headwaters Forest Reserve (HFR) along the Elk River (Hikshari’) Trail in Humboldt County, California. Initially, the project was supervised by the Bureau of Land Management (BLM) Arcata Field Office. However, the 2025 U.S. government …

Spatial Analysis Of American Chestnut (Castanea Dentata) Distribution And Ecology In Kentucky’S Federal Lands, Jacob Raymond Pease

Murray State Theses and Dissertations

Anthropogenic factors have been the cause of the decline of tree species across the globe. From unsustainable logging and development to disease and improper management, threats to forests have taken their toll. The American chestnut (Castanea dentata) was once an integral basal tree species in Appalachian forests, but chestnut blight drove the species to functional extinction by the mid-1900s. The recent creation of genetically modified chestnuts gives hope for future restoration of the species throughout its historical range. Despite blight resistance, effective restoration will require optimal site selection for finding and planting chestnuts, which will maximize limited resources. …

Microbial And Plant Biodiversity In Appalachian Agroecosystems And Their Implications For Soil Health, Kinsey Reed Close

Graduate Theses, Dissertations, and Problem Reports (ETD)

The sustainability of agricultural landscapes depends on understanding the complex interactions between plants, soil, and microbes. In Appalachia, a region shaped by complex terrain and long histories of human and ecological interaction, small family farms produce hay, livestock, and row crops. These agroecosystems, though often treated as “artificial” by many ecologists, have the potential to support both food production and biodiversity conservation if managed with an understanding of ecological complexity. This dissertation examines how plant and microbial diversity interact with soil and management to influence nutrient cycling, soil health, and long-term resilience in Appalachian agricultural systems. A literature review revealed …

A Mystery Of Microecology: Revealing The Ecological Relationship Between Allorhizobium Vitis And Missouri Native Grape Species, Hunter White

Graduate Theses/Dissertations

Crown gall disease can be very detrimental to grape and wine producers around the world by reducing vine vigor and yield. It is caused by the bacteria Allorhizobium vitis (A. Vitis) carrying a tumor inducing (Ti) plasmid. The A. vitis bacteria have been found in soil and cane tissues in vineyards around the world, and infect all cultivated grapes. However, there have been no reports of crown gall on native wild grapevines, and very little is known about the ecology of A. vitis in native ecosystems. I have sampled cambium tissues from three native wild grape species of …

“Nice To See You”: Addressing Plant Awareness Disparity With Locally Specific Ecological And Cultural Plant Education, Cecilia Muecke

Pomona Senior Theses

Plants form the basis of life on Earth. However, due to the phenomenon of plant awareness disparity, a self-perpetuating cycle whereby plants are overlooked on an individual and global level ensues. Lack of plant awareness leads to a lessened emphasis on plants in sustainability and conservation as well as biology education, resulting in negative impacts on biodiversity and food security. The severity of plant awareness disparity is dependent on cultural context, and Indigenous and/or traditional societies are less likely to experience plant awareness disparity because of they are typically more connected to plants for their everyday needs. Native plants are …

Assessing Genetic Diversity And Population Structure In The Imperiled Aconitum Reclinatum (White Monkshood), An Endemic Wildflower Of Central Appalachia, Diamanda A. Zizis

Master’s Theses

Aconitum reclinatum, white monkshood (Ranunculaceae), is a Pennsylvania critically imperiled plant species found in five states of the Appalachian region of the United States: Pennsylvania, West Virginia, Virginia, North Carolina, and Tennessee. This plant is adapted to cool, moist environments but faces threats from increasing habitat loss, deer browse, logging, and changes in rainfall and temperature associated with climate change. Comprehensive knowledge of A. reclinatum genetic population structure remains limited. To address this, we collaborated with Natural Heritage programs within the range of A. reclinatum to sample populations across the species distribution and generate a genotyping-by-sequencing data set of …

Responses Of Native And Invasive Aquatic Vegetation To Changes In Water Depth In An Ozark Spring-Fed Pond, Daphne Miles

Graduate Theses/Dissertations

Spring-fed aquatic ecosystems in the Ozark Highlands are characterized by stable water depths, clear water, and diverse aquatic vegetation (filamentous algae, submerged, floating, and emergent plants). Sudden changes in water depth can impact aquatic vegetation dynamics but the impacts of prolonged changes are poorly understood. I investigated seasonal and annual changes to aquatic vegetation abundance in a spring impoundment during and after a two-year period of low water depth that was caused by a broken outlet below an artificial dam. Water depth was significantly lower in 2020 and 2021 (low water years), compared to 2022 and 2023 (high water years). …

Evaluating The Roles Of Pollinators In Shaping The Floral Color Variation Of Phacelia Dubia, Katherine Riddle

All Theses

Floral color variation within a species is a common occurrence and its maintenance has been a long-standing question in evolutionary biology. Differences in flower color between populations can be shaped by pollinator-mediated selection. Pollinators can exhibit innate and learned preferences for color that may influence floral color variation. These preferences may be molded by the visual environment in which pollinators forage. Most current understanding of how pollinators shape floral color variation involves dramatic differences in dominant pollinators between populations (e.g., hawkmoth vs. bee) and most behavioral work utilized model pollinators like honeybee and bumble bee. However, less is known about …

Determining The Long-Term Effectiveness Of Seeding Post-Dam Removal In The Elwha River, Wa, Through Soil Seed Bank Analysis, Makenna Tabino, Rebecca Brown

2024 Symposium

Following the historic dam removal along the Elwha River in Olympic National Park, we are evaluating the impact of seeding in the former Lake Mills reservoir by examining the soil seed bank composition. The Elwha River had the largest dam removal project in history, and the second largest ecological restoration project in National Parks Service history. Active restoration (seeding and planting) took place in terraces and valley walls, the two dominant landform types found in the former reservoir. While the plant community in the former dam reservoirs is well documented, the soil seed bank remains unexplored.

My objective is to …

Fire And Ant Interactions Mediated By Honeydew And Extrafloral Nectar In An Australian Tropical Savanna, Fernanda M. P. Oliveira, Carlos H. F Silva, Melinda L. Moir, Inara R. Leal, Alan N. Andersen

Natural Resources Research Articles

Fire is a major disturbance affecting ecosystems globally, but its impact on mutualisms has received minimal attention. Here, we use a long-term field experiment to investigate the impact of different fire regimes on globally important ant–honeydew and ant–extrafloral nectar (EFN) mutualistic interactions in an Australian tropical savanna. These interactions provide ants with a key energy source, while their plant and hemipteran hosts receive protection services. We examined ant interactions on species of Eucalyptus (lacking EFNs) and Acacia (with EFNs) in three replicate plots each of burning every 2 and 3 years early in the dry season, burning late in the …

2024 Fall Newsletter, Plaster Creek Stewards

Newsletters

Highlights:

Project GreenER Returns in 2025

Sustainable Business of the Year

PCS Is Showing Up Around the Community

Botanical Highlight: Discovery of a New Kent County Native Grass

Fall Event Furthers New Tree Planting Initiatives

Plaster Creek: Unsalted?

Making Connections at Calvin

Field-Based Courses Still Matter, But Not Like They Used To, Christopher T. Martine

Faculty Journal Articles

Increasingly, field-based courses are providing the first real opportunities for students to experience nature in meaningful ways. As a baseline, even before the content delivery and the graded assessments, this is already enough to change the way a person feels in the world and to spark an appreciation for the life around them.

(Part of a special feature on education in which recent winners of the Botanical Society of America's Charles E. Bessey Award share teaching philosophies and strategies.)

Seed Dispersal By Martu Peoples Promotes The Distribution Of Native Plants In Arid Australia, Rebecca Bliege Bird, Douglas Bird, Christopher T. Martine, Chloe Mcguire, Leanne Greenwood, Desmond Taylor, Tanisha M. Williams, Peter M. Veth

Faculty Journal Articles

Commensal relationships between wild plants and their dispersers play a key ecological and evolutionary role in community structure and function. While non-human dispersers are often considered critical to plant recruitment, human dispersers have received much less attention, especially when it comes to non-domesticated plants. Australia, as a continent historically characterized by economies reliant on non-domesticated plants, is thus a key system for exploring the ecological role of people as seed dispersers in the absence of agriculture. Here, we utilize a controlled observation research design, employing ecological surveys and ethnographic observations to examine how seed dispersal and landscape burning by Martu …

Scientific Note: An Incursion Of The Widely-Cultivated Katsura (Cercidiphyllum Japonicum, Cercidiphyllaceae) In Pennsylvania, Kayleigh R. Long, Melody P. Sain, Elizabeth H. Williams, Christopher T. Martine

Faculty Journal Articles

Cercidiphyllum japonicum (katsura) is a dioecious tree native to China and Japan. Although imperiled in parts of its natural distribution, the species has become quite common as a cultivated tree in temperate North America. The species is noted as occasionally escaping cultivation in the eastern United States, but few records of established incursions (and the conditions under which they might recruit) exist in the literature. We here report an incursion of C. japonicum in central Pennsylvania, along with notes on seedling recruitment on the Bucknell University campus.

New Insights On Hybridization In Potamogeton Floridanus (The Florida Pondweed), Kaitlyn R. Sampson

Graduate Theses and Dissertations (2019 - present)

Freshwater ecosystems are some of the most important and highest threatened habitats in the world, and aquatic plants play an important, but often-overlooked, role in maintaining them. Potamogeton is a diverse and ecologically important aquatic plant genus well known for taxonomic difficulty and rampant hybridization. lbis study aimed to 1) test the hypothesis that Potamogeton jloridanus (Florida pondweed) is a hybrid between P. oakesianus and P. pulcher, and 2) to investigate correlations in ecological conditions for the focal species. This study revealed the discovery of a new population of P. jloridanus in Big Coldwater Creek in Santa Rosa Co., FL, …

Climate And Shared Evolutionary History Drive Trait Variation Among Species Of Neotropical Understory Monocots, Eleinis Ávila-Lovera, Oscar M. Vargas, Jennifer L. Funk, Kathleen M. Kay, Gregory R. Goldsmith

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Environmental variation commonly drives functional trait diversity within species, among species, and across communities. Climate and shared evolutionary history can both influence trait–environment relationships. We studied variation in plant functional traits among closely related Costus species occurring across environmental gradients, the extent to which this variation occurs within single species, and how that variation may be influenced by shared evolutionary history. We measured leaf, aboveground stem, rhizome, and fine root traits of 17 species of Costus in eight sites in Costa Rica and Panama, which varied in elevation, temperature, and precipitation. We then assessed the relationships among traits and environmental …

From Pixels To Plants: Remote Sensing Of California Invasive Plants, Kenneth Rangel

Master's Projects and Capstones

Invasive plants cause significant impacts to ecosystems, the economy, and human health. California has experienced significant plant invasions and is well suited to future invasion because of its Mediterranean climate and human disturbance. Eradication or control of invasive plant species requires a detailed understanding of their spatial distribution, which typically involves on the ground surveys that can be expensive or inconsistent. Remote sensing offers a potential alternative or supplement to in-person invasive plant mapping. This study performed a comparative analysis of 41 remote sensing studies that mapped the distribution of California invasive plants. I found that while high spectral resolution …

Identifying Grassland Cores In The Southeast: Relating Spatial Covariance To Avian Communities And Vegetation Structure, Lauren L. Berry

Graduate Theses and Dissertations

Globally, grasslands are declining in range, which is leading to a decline in grassland-dependent taxa. These declines can be attributed to a variety of issues, a major one being the encroachment of woody species into historic grasslands. There is a new framework for strategizing grassland management, referred to as “Defend the Core,” which calls for proactive management of intact grasslands, meaning conserving remaining grasslands by preventing woody encroachment in the first place. To successfully defend the core, it is imperative that we develop rapid methods to identify intact grassland cores for management priority. One method that can be used for …

Cross-Pollination: Building A Co-Taught Course To Examine Art And Sex Through The Lens Of Botany, Christopher T. Martine, Diamanda A. Zizis, Anna K. Kell

Faculty Journal Articles

Driven by overlapping interests in plants, art, and diversity in sex expression, Anna Kell (Department of Art and Art History) and Chris Martine (Department of Biology) developed a course that integrates the perspectives of a visual artist and a botanist. Art & Sex Through the Lens of Botany seeks to impart the importance of making connections across disciplines and the value of visual literacy across academic lines. The course introduces foundational concepts in each field and encourages students to integrate and explore these different systems of knowledge and their intersections. In addition to developing fluencies related to both general botany …

Relationships, Species Boundaries, And Speciation Of Piper Section Enckea, Cara Jean Hastings

Boise State University Theses and Dissertations

Species are fundamental biological units but defining what constitutes a species has been debated by biologists, philosophers, and other scholars. Our concept of what constitutes a species has evolved over time, reflecting progress and advances in technology and types of data available as well as increased understanding of the complexity of the speciation process. To understand how extant species evolved, it is useful to evaluate their relationships using molecular data in a phylogenetic framework. By pairing phylogenetic data with other types of data including morphological and fossil data as well as topographical and climatic history, we can gain understanding of …

The Genus Centris Fabricius In Cuba, With A New Record And The Description Of A New Species (Hymenoptera: Apoidea: Anthophila), Julio A. Genaro, Dayron Breto

Insecta Mundi

Members of the genus Centris Fabricius (Hymenoptera: Apoidea: Anthophila) constitute a significant component of the Neotropical (including insular) bee fauna, exhibiting high species richness, a moderate to large body size, and extensive interactions with various important plant groups. Females of most species possess specialized morphology adapted for collecting oils from flowers. This study documents the presence of the genus in Cuba, recognizing six species: C. aethiops Cresson, C. cornuta Cresson, C. fulviventris Cresson, C. poecila Lepeletier, C. taina Genaro and Breto new species, and C. tarsata F. Smith. Detailed information is provided for …

Variations In Salinity And Forest Structure Between Marginal And Cloistered Mangrove Forests In Boca Del Drago, Bocas Del Toro, Panama, Mary Elizabeth Hodge

Independent Study Project (ISP) Collection

Mangroves are incredibly important ecosystems that have an outsized impact on their surroundings, providing crucial ecosystem services like carbon sequestration and coastal protection. At the same time, mangroves are some of the most threatened habitats due to their valuable position along tropical coastlines. Globally, mangrove forests are deforested and degraded by aquaculture, tourism developments, urbanization, and overharvesting. Due to high rates of mangrove loss, mangrove deforestation is now illegal in Panama, though this legislation is inconsistent and allows for exceptions, especially in tourism developments. This study aims to probe the impacts of localized coastal developments on a small mangrove forest …

Vascular Epiphyte Population Dynamics Within Human-Modified Landscapes Of Guadalupe, Cerro Punta, Chiriquí, Panamá, Lucine Tashjian

Independent Study Project (ISP) Collection

Epiphytes are plants that grow on other plants non-parasitically, and globally, epiphytes compose a very large and diverse group. They are especially abundant and species-rich in the tropics- particularly, in tropical montane forest ecosystems. Human population growth in the tropics, however, has resulted in significant declines in forest cover with land being converted largely for agricultural purposes. Studies on epiphytes have traditionally been undertaken in pristine, undisturbed forest ecosystems, yet terrestrial land conversion has increased the need to understand the value of human-modified ecosystems for epiphytic populations and biodiversity conservation. This study sought to understand the relationship between human modification …

The Virginia Academy Of Science: A Scholarly Forum Over Decades For Students Of A Plant Ecologist, Stewart Ware

Virginia Journal of Science

As a newcomer to Virginia in 1968, I learned that annual meetings of the Virginia Academy of Science (VAS) were regarded as an excellent place for students to have their first experience giving a talk about their research to fellow scientists, and a place for faculty to get to know other Virginia scientists in their fields. Over the next four decades William and Mary students (undergraduate and graduate) and I were presenters or co-authors of 42 talks or posters at VAS annual meetings, 29 of them based on studies of plant ecology across Virginia. Two were talks by colleagues with …

Interacting Effects Of Nutrient Availability And Environmental Change On Grassland Plant Communities, George Robert Wheeler

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The availability of nutrients plays an important role in shaping the composition, productivity and diversity of plant communities. Such effects are particularly well documented in grassland ecosystems, where both independent studies and collaborations such as the Nutrient Network consistently show increasing productivity and decreasing diversity with the addition of limiting nutrients. The specifics of this pattern, however, vary widely from site to site, and within a single site, they may shift with changes in environmental conditions and disturbance regimes.

My research at Cedar Creek Ecosystem Science Reserve (Minnesota, USA), documents such a pattern through resampling of a long-term experiment on …

The Role Of Geomorphological Context In Vegetative Succession Within The Breiðamerkurjökull Glacial Foreland, Lucas Nerbonne

Independent Study Project (ISP) Collection

As glaciers retreat worldwide at an accelerating pace, understanding primary succession in these newly exposed landscapes becomes increasingly critical. This study examines the initial vegetative colonization patterns in glacial forelands, focusing on the influence of geomorphological formations of resulting plant communities. By analyzing vegetative communities in glaciofluvial and push moraine deposits, this study highlights how the more varied, channelized morphologies of fluvial deposits create potential microclimates better conducive to heterogenous plant colonization than the homogenous terrain of the nearby push moraine. Vegetative coverage, sediment size, and species abundance was collected at 480 sites across 6 different historical glacial extents across …

Effects Of Hemiparasites In Grassland Restorations Are Not Universal, Anna Marie Scheidel, Victoria Borowicz

Faculty Publications – Biological Sciences

Root hemiparasites infiltrate the vascular tissue of host roots to acquire water and nutrients, which often reduces host growth. Hemiparasites are postulated to be keystone species in grassland communities if they suppress dominant species and increase plant community biodiversity, and ecosystem engineers if they increase nutrient accessibility for surrounding species. We examined keystone effects by evaluating species richness and evenness in 1 m2 plots in a recent prairie restoration where Castilleja sessiliflora was naturally present or absent, and in a longer-established prairie restoration with or without Pedicularis canadensis. We examined ecosystem engineer effects by determining nitrate and phosphate concentrations …