Ecology and Evolutionary Biology Commons^™

The Floral Thermal Environment: Physical, Morphological, And Environmental Determinants, And Their Impact On Plant-Pollinator Interactions, Jennifer Apland

All Theses

Anthropogenic climate change is driving major shifts in global temperatures and increases in extreme temperature events that contribute to reduced survival and species loss. To counteract extreme temperatures, many organisms can undergo geographic range shifts or engage in behavioral thermoregulation (e.g., movement to suitable microhabitats). While plants are sessile and thus subject to highly variable ambient temperatures, they have evolved mechanisms to regulate internal floral temperature. Floral thermoregulation may mitigate thermal stress on pollen and ovules and impact plant-pollinator interactions. These mechanisms for thermoregulation are often highly dependent on ambient temperature and solar radiation as most plants are not endothermic. …

Germination Trends Of American Chaffseed, Schwalbea Americana L., And Factors Affecting First-Year Seedling Development, Trenton Miller

All Theses

Following centuries of exploitation and fire suppression, longleaf pine systems are now the focus of many conservation efforts. Efforts to restore populations of Schwalbea americana L. in longleaf pine savannas have been met with frustratingly low recruitment. While past studies have briefly quantified germination rates for Schwalbea, there have not been any studies yet that truly investigate this plant’s germination requirements. Additionally, there has been little research into characterizing the parasitic relationship between Schwalbea and its various host species. We conducted a germination study in a growth chamber that investigated Schwalbea’s germination rate and time to germinates as …

Impacts Of Disturbance And Nutrient Addition On Coastal Dune Arthropod Communities, Kayla Beitzel

Honors Theses

Coastal dune ecosystems are globally distributed ecosystems that occur from the tropics to the poles and serve as the first line of defense during storms. They are critical habitats for a variety of organisms and also play a critical role in stabilizing coastal habitats. These systems face increased pressure via urban development, recreational expansion, and sea-level rise (Newman et al. 2023; Webster et al. 2005). Insects are vital consumers in coastal ecosystems and act as regulators of plant growth. Low-diversity ecosystems, like coastal dune systems, often contain a higher abundance of low-diverse insect consumers (Ripple et al. 2021), which can …

Reducing Inputs And Adding Value To Turfgrass Systems Through Clover Inclusion And Plant Growth-Promoting Rhizobacteria Applications, Paige E. Boyle

All Graduate Theses and Dissertations, Fall 2023 to Present

Recently, the US has seen an expansion in the amount of turfgrass land cover (lawns, parks, roadsides, sports fields, and golf courses), as well as an interest in reducing fertilizer, water, and pesticide use in these grass systems. To help maintain quality and function while reducing resource inputs, two promising approaches have emerged: planting clover into lawns and applying plant growth-promoting rhizobacteria.

White clover and grass mixtures have been studied for their ability to cut down on fertilizer usage and provide a uniform, dark green lawn, but other clover types have not been as widely studied and may provide similar …

Quantifying The Role Of Water Quality On Nitrogen Cycling In A Trophic Estuary, Kayla Gonzalez-Boy

Symposium of Student Scholars

Jobos Bay Estuary is an intertidal, tropical estuary located in southern Puerto Rico. The estuary covers about 12 km² and has a variety of habitats, such as seagrass beds, mangroves, mud flats, and coral reefs, which play important roles in sediment trapping and water quality maintenance. Seagrasses also serve as nursery and feeding grounds and provide shelter for macrofauna. Currently, the role of seagrasses and water quality on nitrogen (N) cycling in trophic estuaries is not well constrained. Understanding variations in sediment-based effects on N cycling rates and transformations, and how they are associated with water quality, is an …

Forest Composition Change And Biophysical Climate Feedbacks Across Boreal North America, Richard Massey, Brendan M. Rogers, Logan T. Berner, Sol Cooperdock, Michelle C. Mack, Xanthe J. Walker, Scott J. Goetz

Aspen Bibliography

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire. This shift in composition has the potential to generate biophysical cooling via increased land surface albedo. Here we use Landsat-derived maps of continuous tree canopy cover and deciduous fractional composition to assess albedo change over recent decades. We find, on average, a small net decrease in deciduous fraction from 2000 to 2015 across boreal North America and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find near-neutral net biophysical change in radiative forcing associated …

2023 Fall Newsletter, Plaster Creek Stewards

Newsletters

Highlights:

Our Year at a Glance

Marketing as Education

Plaster Creek Mystery

Insect Biodiversity Study

Green Team and Wellbeing

Coming in 2024

Variation Of Carbon Stock Of Boca Del Drago Mangrove Forests Based On Salinity And Seaward Proximity, Fiona Wyrtzen

Independent Study Project (ISP) Collection

Mangrove forests, at the intersection of land and sea, are considered one of the most important marine environments for their variety of ecosystem services and their ability to sequester large amounts of carbon in their biomass and adjacent soils. With a changing climate, many of the abiotic and biotic factors influencing mangroves will begin to shift, potentially impacting resilience, growth capacity, and distribution of mangroves worldwide. This study aimed to examine the influence of changing salinity on the carbon stock capacity for Rhizophora mangle and Laguncularia racemosa forests, and the distribution of biomass in each species relative to salinity in …

Belowground Growth Strategies Of Native And Invasive Rhizomatous Perennial Grasses In Response To Precipitation Variability, Clipping, And Competition, Surendra Bam, Jacqueline P. Ott, Jack Butler, Lan Xu

Natural Resource Management Faculty Publications

Invasive clonal species may exhibit different growth strategies than their native clonal competitors. In this study, we examined the spatial distribution of tiller outgrowth and the bud bank by comparing the investment in phalanx versus guerilla growth of a native and invasive perennial grass in North America. We also examined the efect of altered precipitation frequency, clipping, and competition on their clonal growth strategies. Investment in phalanx and guerilla growth was assessed by examining live propagule and tiller production from the plant crown versus its rhizomes. Although invasive Bromus inermis and native Pascopyrum smithii exhibited similar clonal growth strategies as …

Genomic And Transcriptomic Analyses Reveal Polygenic Architecture For Ecologically Important Traits In Aspen (Populus Tremuloides Michx.), Jennifer F. L. Riehl, Christopher T. Cole, Clay J. Marrow, Hilary L. Barker, Carolina Bernhardsson, Kennedy Rubert-Nason, Pär K. Ingvarsson, Richard L. Lindroth

Aspen Bibliography

Intraspecific genetic variations in foundation species such as aspen (Populus tremuloides Michx.) shapes their impact on forest structure and function. Identifying genes underlying ecologically important traits is key to understanding that impact. Previous studies, using single-locus genome-wide association (GWA) analyses to identify candidate genes, have identified fewer genes than anticipated for highly heritable quantitative traits. Mounting evidence suggests that polygenic control of quantitative traits is largely responsible for this "missing heritability" phenomenon. Our research characterized the genetic architecture of 30 ecologically important traits using a common garden of aspect through genomic and transcriptomic analyses. A multilocus association model revealed …

Mineral Licks As A Potential Nidus For Parasite Transmission, William J. Severud, Todd M. Kautz, Jerrold L. Belant, Seth A. Moore

Natural Resource Management Faculty Publications

Discrete landscape features can concentrate animals in time and space, leading to non-random interspecific encounters. These encounters have implications for predator-prey interactions, habitat selection, intraspecific competition, and transmission of parasites and other pathogens. The lifecycle of the parasitic nematode Parelaphostrongylus tenuis requires an intermediate host of a terrestrial gastropod. Natural hosts of P. tenuis are whitetailed deer, and an aberrant host of conservation concern is moose, which are susceptible to high levels of mortality as a naive host to the parasite. Intermediate hosts become infected when P. tenuis larvae are shed in deer feces, then consumed or enter the gastropod …

Factors Affecting California Grassland Biodiversity: Two Case Studies, Nora Bales

Master's Theses

Biodiversity loss over the last century has been significant and is projected to increase. Biodiversity loss is accelerating due to climate change and habitat loss and degradation. Biodiversity supports key ecosystem services including pollination services, climate regulation, and water filtration. Biodiversity conservation is a top priority for land managers and researchers, however many ecological studies with practical applications lack a thorough understanding of the soil environment in their study system. We conducted two case studies integrating soil and plant data to answer management questions. The first case study investigated the relationship between a threatened plant, Hooveria purpurea var. purpurea and …

Bison Alter The Northern Yellowstone Ecosystem By Breaking Aspen Saplings, Luke E. Painter, Robert L. Beschta, William J. Ripple

Aspen Bibliography

The American bison (Bison bison) is a species that strongly interacts with its environment, yet the effects of this large herbivore on quaking aspen (Populus tremuloides) have received little study. We documented bison breaking the stems of aspen saplings (young aspen > 2 m tall and ≤ 5 cm in diameter at breast height) and examined the extent of this effect in northern Yellowstone National Park (YNP). Low densities of Rocky Mountain elk (Cervus canadensis) after about 2004 created conditions conducive for new aspen recruitment in YNP's northern ungulate winter range (northern range). We sampled …

Particle Drift Potential Of Mesotrione And Rimsulfuron Plus Thifensulfuron-Methyl Tank Mixture In A Low-Speed Wind Tunnel, Milan Brankov, Guilherme Sousa Alves, Bruno Canella Vieira, Milos Zaric, Greg R. Kruger

West Central Research and Extension Center, North Platte

Particle drift happens during herbicide application when droplets travel outside the intended site. Different nozzles produce various range of droplets, so they play a very important role in coverage and drift occasions. When nozzles produce small droplets, the potential for off-target movement is very high. Another important factor determining particle drift is the distance between crops. Wind velocity gives the energy to herbicide particles to move away from the target place. Therefore, a drift simulation of herbicide (mesotrione and rimsulfuron plus thifensulfuron-methyl mixture) was done in a wind tunnel, using different nozzles Extended Range (XR) and Turbo TeeJet Induction (TTI). …

Evidence Of Competitive Release Following Overstory Mortality In A Semi-Arid Piñon-Juniper Woodland, Corrie D. Gonzalez

Biology ETDs

Extreme temperatures and severe drought events have led to widespread tree mortality worldwide. In semi-arid regions of the Southwest United States, these events pose a significant threat to piñon-juniper (PJ) woodlands. We studied the effects of piñon and juniper mortality on the growth and physiology of existing saplings in PJ woodlands by analyzing water status, photosynthetic activity, and tissue chemistry to gain insights into these impacts. Juniper saplings exhibited improved water status and water use efficiency in response to overstory mortality, whereas piñon saplings did not. Additionally, both piñon and juniper saplings exhibited increased photosynthetic rates, increased photosynthetic capacity, and …

Impacts Of Urbanization On Pollination Success For Common Milkweed (Asclepias Syriaca), David Rockow

Electronic Theses and Dissertations

Urbanization is among the greatest threats to biodiversity on the planet, and is projected to increase in magnitude in coming years. This growing threat makes it important to better understand how urbanization may impact vital ecosystem services, such as pollination. Studies on the impact of urbanization on pollination vary wildly in their findings. This study analyzed multiple aspects of pollination success in common milkweed populations varying in urbanization level, including insect community composition, pollen removal/deposition, and fruit/seed production. By analyzing multiple pollination aspects we can determine the overall mechanism in which urbanization instills on the entire pollination process. Overall, urbanization …

Influence Of Abiotic Drivers And Plant Community Interactions On Bald Cypress (Taxodium Distichum) Seedlings: Implications For Restoration, Victoria Ellis

Biological Sciences Theses & Dissertations

Forested freshwater wetlands are valuable ecosystems that provide habitat for numerous species, sequester carbon, and act as sinks for excess water and nutrients. Historically, these ecosystems have been heavily degraded by anthropogenic activities leading to loss of ecosystem services and a desire to restore freshwater forested wetland habitat. Thus, science-backed approaches for the restoration of freshwater forested wetlands are necessary to ensure restoration goals are met. This body of research employed the Stress Gradient Hypothesis to test whether a multi-species planting approach using Juncus effusus (L.) (soft rush) could facilitate the survival of Taxodium distichum (L.) Rich. (bald cypress) seedlings …

Beef Color And Tenderness Response To Production Systems Utilizing Additive Combinations Of Growth-Promotant Technologies, Megan J. Webb, Janna J. Block, John R. Jaeger, R. Funston, Michael G. Gonda, Keith R. Underwood, Judson K. Grubbs, Kenneth C. Olson, Amanda D. Blair

West Central Research and Extension Center, North Platte

The objective of this study was to compare the influence of beef production systems using additive combinations of growth-promotant technologies on meat quality. Steer calves (n = 120) were assigned to 1 of 4 treatments: 1) no technology (NT; control), 2) antibiotic treated (ANT; NT plus therapeutic antibiotics, monensin, and tylosin), 3) implant treated (IMP; ANT plus a series of three implants), and 4) beta-agonist treated (BA; IMP plus ractopamine-HCl). Muscle biopsy samples from the longissimus lumborum were extracted from a subset (n = 4 per treatment) of steers to evaluate expression of calpain-1, calpain-2, and calpastatin using …

Variable Synchrony In Insect Outbreak Cycling Across A Forest Landscape Gradient: Multi-Scale Evidence From Trembling Aspen In Alberta, Barry J. Cooke, Jens Roland

Aspen Bibliography

Using multi-scale trembling aspen tree-ring width data from Alberta, we show that scaling has a profound influence on dendroecological inferencing. At all scales of sampling, there is a significant climatological signal whose strength is nevertheless superseded by the pervasive effect of insect herbivory. At the smallest spatial scale, 20 km x 20 km, we demonstrate a quasi-periodic pattern of sharp growth reductions and the existence of negative spatial correlations among successive outbreaks. At the intermediate spatial scale of 20 km x 80 km, we show that the period 1930-1963 was marked by extremely low correlations in aspen ring widths, with …

Morphological Trait Evolution In Solanum (Solanaceae): Evolutionary Lability Of Key Taxonomic Characters, Rebecca Hilgenhof, Edeline Gagnon, Sandra Knapp, Xavier Aubriot, Eric Tepe, Lynn Bohs, Leandro Giacomin, Yuri Gouvea, Andres Orejuela, Christopher T. Martine, Clara Ines Orozco, Iris E. Peralta, Tina Sarkinen

Faculty Journal Articles

Solanum is one of the world's largest and economically most important plant genera, including 1245 currently accepted species and several major and minor crops (e.g., tomato, potato, brinjal eggplant, scarlet eggplant, Gboma eggplant, lulo, and pepino). Here we provide an overview of the evolution of 25 key morphological traits for the major and minor clades of this giant genus based on stochastic mapping using a well-sampled recently published phylogeny of Solanum. The most evolutionarily labile traits (showing >100 transitions across the genus) relate to plant structure (growth form and sympodial unit structure), herbivore defence (glandular trichomes), pollination (corolla shape …

Pathogen Emergence As Complex Biological Invasion: Lessons From Dynamical Systems Modeling, Sudam Surasinghe, Marisabel Rodriguez, Victor Meszaros, Jane Molofsky, Salvador Almagro-Moreno, Brandon Ogbunugafor

Northeast Journal of Complex Systems (NEJCS)

Infectious disease emergence has become the target of cross-disciplinary efforts
that aim to understand and predict the shape of outbreaks. The many challenges
involved with the prediction of disease emergence events is a characteristic that in-
fectious diseases share with biological invasions in many subfields of ecology (e.g.,
how certain plants are able to successfully invade a new niche). Like infectious
diseases, biological invasions by plants and animals involve interactions between
agents (pathogens and plants in their respective cases) and a recipient niche. In
this study, we examine the problem of pathogen emergence through the lens of a
framework first …

2023 Summer Newsletter, Plaster Creek Stewards

Newsletters

Highlights:

A Summer of Growth

Plaster Creek Has Mussels

Growing with the Green Team

Come See the Plaster Creek Mural

Lot 16: Calvin's New Bioswale

Welcome, Matt!

Student Research

Summer Reflections

Do Species Matter? Examining The Niche Of White Ash (Fraxinus Americana L.) And Estimating Potential Subcanopy Effects Of Its Loss In North-Temperate Forests, Elizabeth Anne Studer

Dartmouth College Ph.D Dissertations

To understand the downstream consequences of the extinction of a species, we must understand its role in an ecosystem. With the impending extirpation of ash (Fraxinus spp.) due to the invasive emerald ash borer (Agrilus planipennis), understanding the role of ash trees is critical to predicting whether its loss will precipitate further species declines and/or ecosystem functions. We evaluated whether subcanopy microbial, invertebrate, and floral communities under four tree species (white ash, American beech, yellow birch, sugar maple) and on two soil hydropedological types (Bh podzol and Typical podzol) varied in species richness, composition, and functional traits in a factorial …

Tamaulipan Thornforest Restoration: Factors Influencing Restoration Outcomes And Impacts Of Cover Crops During Replanting, Jerald T. 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 …

Cadmium And Salinity Stressor Antagonism On Vallisneria Neotropicalis, Christopher P. Mikolaitis

Graduate Theses and Dissertations (2019 - present)

Submerged macrophytes form the foundation of freshwater ecosystems. These organisms are sessile and are very susceptible to shifts in their environment. Heavy metals are of particular concern as they can be sequestered indefinitely in sediments and are readily taken up by rooted vegetation. In the presence of saltwater intrusions, these metals can interact with salt ions potentially changing their availability to submerged vegetation. In this study a freshwater macrophyte, Vallisneria neotropicalis, was used as a test species for interactive effects between Cd, a non-essential heavy metal, and salt stress. The metrics used to establish the individual as well as …

Comparisons Of Above- And Below-Ground Carbon Storage In A Northeastern Illinois Urban Forest Following Rhamnus Cathartica And Fraxinus Spp. Removal, River Sanchez-Dudik, Elene Drosos

DePaul Discoveries

This study focused on quantifying potential differences in ecosystem services (carbon storage, soil organic matter, macroarthropod density) in a small, partially restored urban forest in order to determine if common buckthorn and standing dead ash removal effects can be detected while restoration is on-going. We calculated aboveground carbon storage (tons/total area) using whole tree biomass equations and compared this to i-Tree Canopy estimations. We collected SOM through loss-on-ignition and collected macroinvertebrates by pitfall trapping to determine differences along transects. Aboveground carbon storage, soil organic matter, and macroinvertebrate total results for this study were found to be statistically not significant, indicating …

Animal Communication And Sentience, Catia Correia-Caeiro, Katja Liebal

Animal Sentience

Segundo-Ortin & Calvo (S&C) argue for sentience in plants on the basis of several studies of what they describe as "cognitive abilities" in plants. As other commentaries (e.g., Brooks Pribac, 2023; Damasio & Damasio, 2023; ten Cate, 2023) have pointed out, however, there is some misuse of several concepts, and a lack of evidence for sentience. We try to clarify three questions in S&C’s discussion: (1) How is communication defined and conceptualised in animal research? (2) Is plant communication comparable to animal communication? (3) Is communication (or the process we see in plants) a good basis for inferring sentience in …

A Remote Sensing Approach To Assess The Historical Invasion Of Phragmites Australis In A Brackish Coastal Marsh, Jason S. Hagani, John Y. Takekawa, Steven C. Chappell, Richelle L. Tanner, Adrienne R. Ernst, Karin M. Kettenring

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Introduction: Coastal estuarine wetlands provide important habitats for a variety of endemic flora and fauna but are particularly vulnerable to biological invasions. Regular monitoring of changes in these vulnerable wetlands has become increasingly important for effective management, especially considering threats from climate change effects and human disturbance. Historical analyzes of plant invasions may guide targeted management strategies to eradicate harmful species. Estimating the distribution of invasive species has never been more accessible with the improved availability of high-resolution data and innovations in remote sensing, estimating the distribution of invasive species has never been more accessible.

Methods: We assessed the spread …

Fluidity And Inconstancy: Australian Bush Tomatoes As An Exemplar Of Non-Normative Sex Expression, Christopher T. Martine

Faculty Journal Articles

Solanum, a genus of ~1500 global species, is one of the more interesting plant groups in which to study reproductive biology and ecology. Overwhelmingly, species in this group express full cosexuality, where individual plants have flowers containing both fully-functioning “male” (staminate) and “female” (carpellate) organs. However, there have been multiple and widespread evolutionary transitions within the genus to non-normative variations on this ancestral condition. Australian bush tomatoes (ca. 40 species) are especially diverse in this regard, with uncommon variation and combinations of unisexuality and cosexuality -- including, most notably, two sexual systems known as dioecy (unisexual male or female …

A Foundational Population Genetics Investigation Of The Sexual Systems Of Solanum (Solanaceae) In The Australian Monsoon Tropics Suggests Dioecious Taxa May Benefit From Increased Genetic Admixture Via Obligate Outcrossing, Jason T. Cantley, Ingrid E. Jordon-Thaden, Morgan Roche, Daniel S. Hayes, Stephamie Kate, Christopher T. Martine

Faculty Journal Articles

Solanum section Leptostemonum is an ideal lineage to test the theoretical framework regarding proposed evolutionary benefits of outcrossing sexual systems in comparison to cosexuality. Theoretically, non-cosexual taxa should support more genetic diversity within populations, experience less inbreeding, and have less genetic structure due to a restricted ability to self-fertilize. However, many confounding factors present challenges for a confident inference that inherent differences in sexual systems influence observed genetic patterns among populations. This study provides a foundational baseline of the population genetics of several species of different sexual systems with the aim of generating hypotheses of any factor—including sexual system—that influences …