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Articles 1 - 30 of 88

Full-Text Articles in Biology

The Interactions Between Drought Tolerant Corn Hybrids And Plant Water-Stress On Weeds And Their Host Capability For Spider Mites, Mercy Adhiambo Odemba Aug 2024

The Interactions Between Drought Tolerant Corn Hybrids And Plant Water-Stress On Weeds And Their Host Capability For Spider Mites, Mercy Adhiambo Odemba

All Graduate Theses and Dissertations, Fall 2023 to Present

With climate change, it is predicted that more frequent high temperatures and drought severity will lead to an increase in damage caused by pests that thrive under these conditions. Spider mite outbreaks, for example, are associated with plant waterstress and there is evidence that some weeds are more resilient and adapted to drought than some crops, leading to major concerns for the management of these two pest types. Weeds directly compete with crops for limited resources, but what is unclear is which weeds harbor spider mites and whether they exacerbate the impact of spider mites on corn crops under water-stressed …

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The Effect Of Urbanization And Temperature On Thermal Tolerance, Foraging Performance, And Competition In Cavity-Dwelling Ants, Brooke A. Harris, Dale Stevens, Kaitlyn A. Mathis Feb 2024

The Effect Of Urbanization And Temperature On Thermal Tolerance, Foraging Performance, And Competition In Cavity-Dwelling Ants, Brooke A. Harris, Dale Stevens, Kaitlyn A. Mathis

Biology

Human disturbance including rapid urbanization and increased temperatures can have profound effects on the ecology of local populations. Eusocial insects, such as ants, have adapted to stressors of increasing temperature and urbanization; however, these evolutionary responses are not consistent among populations across geographic space. Here we asked how urbanization and incubation temperature influence critical thermal maximum (CTmax) and various ecologically relevant behaviors in three ant species in urban and rural locations in Worcester, MA, USA. We did this by incubating colonies of three species of cavity dwelling ant (Aphaenogaster picea, Tapinoma sessile, and Temnothorax longispinosus) from 2 habitat …

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Investigating The Role Of Plant Traits And Interactions In Emergent Wetland Nutrient Removal, Andrew Ryan Sample Aug 2023

Investigating The Role Of Plant Traits And Interactions In Emergent Wetland Nutrient Removal, Andrew Ryan Sample

Theses and Dissertations

Increasing wetland restoration in the Lower Mississippi Alluvial Valley has been identified as a method to reduce nutrient loading in the Gulf of Mexico. Wetlands have historically been used to treat water through processes facilitated by wetland plants, and relatively few species and plant traits have been identified as important in carrying out these processes. This study focuses on some of those species and traits and aims to identify species differences and plant traits that may be important for wetland nutrient mitigation. Chapter I provides background information on nutrient pollution, wetland biogeochemical mechanisms for nutrient sequestration, and the focal species …

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Interactions Between Chytrids Cause Variable Infection Strategies On Harmful Algal Bloom Forming Species, Katelyn M. Mckindles, R. Michael L. Mckay, George S. Bullerjahn, Thijs Frenken Feb 2023

Interactions Between Chytrids Cause Variable Infection Strategies On Harmful Algal Bloom Forming Species, Katelyn M. Mckindles, R. Michael L. Mckay, George S. Bullerjahn, Thijs Frenken

Great Lakes Institute for Environmental Research Publications

Cyanobacteria have a great diversity of natural enemies, such as herbivores and pathogens, including fungal pathogens within the Chytridiomycota (chytrids). While these pathogens have been previously described on a select number of cyanobacterial hosts and are suspected to play a significant ecological role, little is understood about species interactions and how competition between parasites can affect epidemic development and bloom formation. Here, three Planktothrix agardhii isolates from Sandusky Bay, Lake Erie (OH, USA) were challenged in monoculture and polyculture against infection by three isolates (C1, C2, C10) of their obligate chytrid fungal pathogen, Rhizophydiales sp. The chytrid isolates were inoculated …

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Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer Jan 2023

Competition And Herbivory Influence The Survival, Growth, And Physiology Of Native Tree Seedlings In The Kentucky Inner Bluegrass Savanna-Woodland, James D. Shaffer

Theses and Dissertations--Biology

Terrestrial plant communities are shaped by competition for resources, herbivory, and abiotic processes. Savanna systems represent a dynamic coexistence of contrasting life forms (grasses and trees) shaped by competition and disturbance. The Kentucky Inner Bluegrass Savanna-Woodland (KIBSW) is described as an open woodland of shade intolerant species; however, climatic, and edaphic conditions can support closed-canopy forest. After European pioneer settlement (c1750-1800), over 99% of “savanna-woodlands” have been lost. KIBSW remnants are experiencing a recruitment failure, leading to a dominance shift in tree communities. I researched how tree-grass competition and mammalian herbivory influence KIBSW regeneration and maintenance. The KIBSW does not …

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Multiple Interacting Stressors Influence Development, Growth, And Morphology Of Pacific Chorus Frog (Pseudacris Regilla) Larvae, Abby Dalke, Allie M. Erickson, Bailey R. Tasker, Skylar Riley, Paul Hurst, Sarah Cooney, Scott A. Griffith, Betsy A. Bancroft Jan 2023

Multiple Interacting Stressors Influence Development, Growth, And Morphology Of Pacific Chorus Frog (Pseudacris Regilla) Larvae, Abby Dalke, Allie M. Erickson, Bailey R. Tasker, Skylar Riley, Paul Hurst, Sarah Cooney, Scott A. Griffith, Betsy A. Bancroft

Biology Faculty Scholarship

Freshwater ecosystems are threatened by climate change and invasive species. Amphibians are important members of freshwater communities and are susceptible to negative effects of climate change and invasion. Furthermore, both climate change and invasion can influence density of amphibian larvae at the microhabitat scale because of larval clustering. To understand the effects of climate change and invasion on Pacific Chorus Frog Pseudacris regilla (Baird and Girard, 1852) larvae, a 2 × 2 × 2 factorial experiment was carried out with a climate treatment (future/historical; simulated as changes in both temperature and hydroperiod), indirect exposure to the invasive Brook Stickleback Culaea …

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Lianas Decelerate Tropical Forest Thinning During Succession, Jose A. Medina-Vega, Geertje M. F. Van Der Heijden, Stefan A. Schnitzer Jun 2022

Lianas Decelerate Tropical Forest Thinning During Succession, Jose A. Medina-Vega, Geertje M. F. Van Der Heijden, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

The well-established pattern of forest thinning during succession predicts an increase in mean tree biomass with decreasing tree density. The forest thinning pattern is commonly assumed to be driven solely by tree-tree competition. The presence of non-tree competitors could alter thinning trajectories, thus altering the rate of forest succession and carbon uptake. We used a large-scale liana removal experiment over 7 years in a 60- to 70-year-old Panamanian forest to test the hypothesis that lianas reduce the rate of forest thinning during succession. We found that lianas slowed forest thinning by reducing tree growth, not by altering tree recruitment or …

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Mycophagous Beetle Females Do Not Behave Competitively During Intrasexual Interactions In Presence Of A Fungal Resource, L. D. Mitchem, Vincent A. Formica, R. Debray, Dana E. Homer , '21, E. D. Brodie Iii Jun 2022

Mycophagous Beetle Females Do Not Behave Competitively During Intrasexual Interactions In Presence Of A Fungal Resource, L. D. Mitchem, Vincent A. Formica, R. Debray, Dana E. Homer , '21, E. D. Brodie Iii

Biology Faculty Works

Intrasexual interactions can determine which individuals within a population have access to limited resources. Despite their potential importance on fitness generally and mating success especially, female–female interactions are not often measured in the same species where male–male interactions are well-defined. In this study, we characterized female–female interactions in Bolitotherus cornutus, a mycophagous beetle species native to Northeastern North America. We used dyadic, behavioral assays to determine whether females perform directly aggressive or indirectly exclusionary competitive behaviors. Polypore shelf fungus, an important food and egg-laying resource for B. cornutus females, is patchily distributed and of variable quality, so we tested …

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Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin Schroeder May 2022

Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin Schroeder

Biology ETDs

As some of the most charismatic megafauna to ever walk the earth, the physiology, morphology, growth and evolution of non-avian theropods has been studied exhaustively, yet little is understood about their roles in ecosystems as juveniles. For carnivorous megatheropods, which exceed 1,000kg in mass yet hatched from eggs of limited size, the likelihood of utilizing different prey through ontogeny was high, simply by proxy of the immense difference in size between adults and juveniles. We found these ontogenetic niche shifts, evidenced by significantly different dental microwear in Tyrannosaurids, to have excluded dinosaurian mesocarnivores from Mesozoic communities. The few dinosaurian mesocarnivores …

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Evolution Of Floral Microbes And The Resulting Effects On Pollinator Preference, Hailey Hatch May 2022

Evolution Of Floral Microbes And The Resulting Effects On Pollinator Preference, Hailey Hatch

Undergraduate Honors Capstone Projects

Floral microbes are an overlooked aspect of the extended floral phenotype. Through altering floral nectar chemistry, they can mediate interactions between flowers, pollinators, and other floral microbes, with significant implications for plant and pollinator health. Interactions between floral microbes and pollinators are critically important to understand, as pollinators provide important ecosystem services in both natural and agriculture systems. Here, I explored how floral nectar traits affected both evolution and competition within the floral yeast Metschnikowia reukaufii, the floral bacterium Bacillus subtilis, and other microbes isolated from Brassica rapa nectar, an important plant model system and oilseed crop. To …

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Lianas Significantly Reduce Aboveground And Belowground Carbon Storage: A Virtual Removal Experiment, Sergio Estrada-Villegas, Sara Sofia Pedraza Navaez, Adriana Sanchez, Stefan A. Schnitzer Feb 2022

Lianas Significantly Reduce Aboveground And Belowground Carbon Storage: A Virtual Removal Experiment, Sergio Estrada-Villegas, Sara Sofia Pedraza Navaez, Adriana Sanchez, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Lianas are a quintessential tropical plant growth-form; they are speciose and abundant in tropical forests worldwide. Lianas compete intensely with trees, reducing nearly all aspects of tree performance. However, the negative effects of lianas on trees have never been combined and quantified for multiple tropical forests. Here, we present the first comprehensive standardized quantification of the effect of lianas on trees across tropical forests worldwide. We used data from 50 liana removal experiments and quantified the effect size of lianas on tree growth, biomass accretion, reproduction, mortality, leaf water potential, sap flow velocity, and leaf area index (LAI) across different …

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Data From: Recovery From Discrete Wound Severities In Side-Blotched Lizards (Uta Stansburiana): Implications For Energy Budget, Locomotor Performance, And Oxidative Stress, Susannah S. French, Spencer B. Hudson Feb 2021

Data From: Recovery From Discrete Wound Severities In Side-Blotched Lizards (Uta Stansburiana): Implications For Energy Budget, Locomotor Performance, And Oxidative Stress, Susannah S. French, Spencer B. Hudson

Browse all Datasets

Wounding events (predation attempts, competitive combat) result in injuries and/or infections that induce integrated immune responses for the recovery process. Despite the survival benefits of immunity in this context, the costs incurred may require investment to be diverted from traits contributing to immediate and/or future survival, such as locomotor performance and oxidative status. Yet, whether trait constraints manifest likely depends on wound severity and the implications for energy budget. For this study, food intake, body mass, sprint speed, and oxidative indices (reactive oxygen metabolites, antioxidant capacity) were monitored in male side-blotched lizards (Uta stansburiana) healing from cutaneous wounds of discrete …

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Sister Species Diverge In Modality-Specific Courtship Signal Form And Function, Eileen Hebets, Mitch Bern, Rowan H. Mcginley, Andy Roberts, Arik Kershenbaum, James Starrett, Jason E. Bond Jan 2021

Sister Species Diverge In Modality-Specific Courtship Signal Form And Function, Eileen Hebets, Mitch Bern, Rowan H. Mcginley, Andy Roberts, Arik Kershenbaum, James Starrett, Jason E. Bond

School of Biological Sciences: Faculty Publications

Understanding the relative importance of different sources of selection (e.g., the environment, social/sexual selection) on the divergence or convergence of reproductive communication can shed light on the origin, maintenance, or even disappearance of species boundaries. Using a multistep approach, we tested the hypothesis that two presumed sister species of wolf spider with overlapping ranges and microhabitat use, yet differing degrees of sexual dimorphism, have diverged in their reliance on modality- specific courtship signaling. We predicted that male Schizocosa crassipalpata (no ornamentation) rely predominantly on diet-dependent vibratory signaling for mating success. In contrast, we predicted that male S. bilineata (black foreleg …

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Effects Of Wolf And Grizzly Bear Recovery On Cougars In A Multi-Use System, Jennifer A. Feltner Jan 2021

Effects Of Wolf And Grizzly Bear Recovery On Cougars In A Multi-Use System, Jennifer A. Feltner

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.

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Exposing Lettuce Plants To Cyanobacteria In A Closed Hydroponics System To Reduce Cyanobacterial Growth And Production, Emily Eberly Dec 2020

Exposing Lettuce Plants To Cyanobacteria In A Closed Hydroponics System To Reduce Cyanobacterial Growth And Production, Emily Eberly

Honors Projects

Sandusky Bay is largely populated by cyanobacterial algal blooms, mainly formed by Planktothrix. Fertilizers containing nitrogen and phosphorus run from agricultural lands into the bay, building up excess nutrients forming eutrophic waters. The Planktothrix feed off these nutrients and grow into algal blooms. To determine a potential solution to the growth of these blooms, I implemented a hydroponics system involving Lactuca Sativa for analysis of Planktothrix growth and productivity. Four different nutrient conditions were added to a Planktothrix-only solution and a solution growing Planktothrix with the lettuce in the hydroponics system. The four conditions consisted of no nutrient …

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Can Functional Traits Explain Plant Coexistence? A Case Study With Tropical Lianas And Trees, Felipe N. A. Mello, Sergio Estrada Villegas, David M. Defilippis, Stefan A. Schnitzer Oct 2020

Can Functional Traits Explain Plant Coexistence? A Case Study With Tropical Lianas And Trees, Felipe N. A. Mello, Sergio Estrada Villegas, David M. Defilippis, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Organisms are adapted to their environment through a suite of anatomical, morphological, and physiological traits. These functional traits are commonly thought to determine an organism’s tolerance to environmental conditions. However, the differences in functional traits among co-occurring species, and whether trait differences mediate competition and coexistence is still poorly understood. Here we review studies comparing functional traits in two co-occurring tropical woody plant guilds, lianas and trees, to understand whether competing plant guilds differ in functional traits and how these differences may help to explain tropical woody plant coexistence. We examined 36 separate studies that compared a total of 140 …

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The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R Michael Mckay Jun 2020

The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R Michael Mckay

Biological Sciences Faculty Publications

Blooms of the toxin-producing cyanobacterium are increasing globally, leading to the loss of ecosystem services, threats to human health, as well as the deaths of pets and husbandry animals. While nutrient availability is a well-known driver of algal biomass, the factors controlling "who" is present in fresh waters are more complicated. possesses multiple strategies to adapt to temperature, light, changes in nutrient chemistry, herbivory, and parasitism that provide a selective advantage over its competitors. Moreover, its ability to alter ecosystem pH provides it a further advantage that helps exclude many of its planktonic competitors. While decades of nutrient monitoring have …

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The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R. Michael L. Mckay May 2020

The Complicated And Confusing Ecology Of Microcystis Blooms, Steven W. Wilhelm, George S. Bullerjahn, R. Michael L. Mckay

Great Lakes Institute for Environmental Research Publications

Blooms of the toxin-producing cyanobacterium Microcystis are increasing globally, leading to the loss of ecosystem services, threats to human health, as well as the deaths of pets and husbandry animals. While nutrient availability is a well-known driver of algal biomass, the factors controlling “who” is present in fresh waters are more complicated. Microcystis possesses multiple strategies to adapt to temperature, light, changes in nutrient chemistry, herbivory, and parasitism that provide a selective advantage over its competitors. Moreover, its ability to alter ecosystem pH provides it a further advantage that helps exclude many of its planktonic competitors. While decades of nutrient …

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Impacts Of Smooth Pigweed (Amaranthus Hybridus) On Cover Crops In Southern Ontario, Heather Vanvolkenburg, Frédérique C. Guinel, Liette Vasseur Apr 2020

Impacts Of Smooth Pigweed (Amaranthus Hybridus) On Cover Crops In Southern Ontario, Heather Vanvolkenburg, Frédérique C. Guinel, Liette Vasseur

Biology Faculty Publications

Amaranthus hybridus is a noxious weed in Ontario, with demonstrated allelopathic properties that can lead to decreased agricultural production. We tested the germination and growth of five cover crop species exposed to A. hybridus extracts, and to dried or fresh materials in soil. A germination index was calculated, and the dry weight of plant organs were measured to quantify responses to treatments. All species had reduced germination (≤29%) in 100% extract. Trifolium pratense had significant root weight reductions in extract (52%) and dried (72%) treatments, whereas shoot weight only decreased (48%) in dried treatment. Medicago sativa shoot weight decreased (52%) …

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Using Stable Isotopes And Diet Analysis To Assess The Potential For Competition And Coexistence Among Coyotes (Canis Latransl, Red Foxes (Vulpes Vulpes), And Gray Foxes (Urocyon Cinereoargenteus) In Maine, Henry M. Masters Apr 2020

Using Stable Isotopes And Diet Analysis To Assess The Potential For Competition And Coexistence Among Coyotes (Canis Latransl, Red Foxes (Vulpes Vulpes), And Gray Foxes (Urocyon Cinereoargenteus) In Maine, Henry M. Masters

Student Scholarship

When two species compete for food, one species typically outcompetes the other. Subordinate species can alleviate costs of competition by reducing diet overlap, promoting coexistence. Non-native coyotes (Canis latrans) and historically native gray foxes (Urocyon cineroargenteus) have expanded their range in Maine and may compete with native red foxes (Vulpes vulpes). To investigate competition, I analyzed stable isotopes and stomach contents to determine if coyotes, red foxes, and gray foxes differed in use of anthropogenic foods and trophic position. I predicted that coyotes utilize anthropogenic foods the least (lowest δ13C), and red foxes utilize …

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Predator-Dependent Functional Responses Alter The Coexistence And Indirect Effects Among Prey That Share A Predator, Kyle E. Coblentz, John P. Delong Jan 2020

Predator-Dependent Functional Responses Alter The Coexistence And Indirect Effects Among Prey That Share A Predator, Kyle E. Coblentz, John P. Delong

School of Biological Sciences: Faculty Publications

Predator functional responses describe predator feeding rates as a function of prey abundance and are central to pred-ator–prey theory. Despite ample evidence that functional responses also depend on predator abundance, theory incor-porating predator-dependent functional responses has focused almost exclusively on specialist predator–prey pairs or linear food chains. This leaves a large gap in our knowledge as many predators feed on multiple prey, and in so doing, generate indirect effects among prey that can alter their coexistence. Here we investigate how predator-dependent functional responses in a one predator–two prey model alter the coexistence among prey and their net effects on one …

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The Rattle Call: A Female-Specific Vocalization In Steller's Jays, Kachina L. Rowland Jan 2020

The Rattle Call: A Female-Specific Vocalization In Steller's Jays, Kachina L. Rowland

Cal Poly Humboldt theses and projects

While the elaborate songs of male passerines are well documented for their role in intrasexual resource competition and mate attraction, vocalizations used in female competition are poorly understood. Research has suggested that the female-specific rattle call of Steller’s jays (Cyanocitta stelleri) is used in competition for access to a territory and mate. I describe structural properties of the rattle call, and compare life history traits of individual females to rattle call occurrence. I used two rates to quantify rattle call occurrence from 20 females: rattles per observation period (RPO), and proportion of observations with a rattle call (POR) …

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Assessing Threats And Mitigation For Scarlet Ammannia (Ammannia Robusta) In Southwestern Ontario, Kayla Salive Jan 2020

Assessing Threats And Mitigation For Scarlet Ammannia (Ammannia Robusta) In Southwestern Ontario, Kayla Salive

Theses and Dissertations (Comprehensive)

Scarlet Ammannia (Ammannia robusta) is an annual emergent wetland plant of the Lythraceae family. Throughout most of its distribution, the species population is stable under present conditions. However, this is not the case in Canada, where A. robusta is considered endangered with only a few small populations documented in British Columbia and Ontario. In response, a recovery strategy was created for A. robusta outlining the lack of information on the species biology and ecology, with a primary objective to assess the populations in Ontario and gain information on what may be contributing to the species rarity. To assess …

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Effects Of Sport Fishing On Harbor Seal Hunting Success, Madison Mckay May 2019

Effects Of Sport Fishing On Harbor Seal Hunting Success, Madison Mckay

Scholars Week

Competitive interactions between marine mammals and fisheries are well documented. For example, pinnipeds (seals and sea lions) may impede the recovery of commercial fish stocks, and fisheries can negatively affect seals via bycatch and by diminishing food availability. However, the interactions between pinnipeds and sport fishers are not well documented, despite the fact that both utilize the same resources. I aimed to investigate whether sport fishermen affect the hunting success of harbor seals (Phoca vitulina). Whatcom Creek, a small and accessible river located in downtown Bellingham, WA, is a common place for sport fishers and harbor seals to aggregate and …

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What Does The Snake Eat? Breadth, Overlap, And Non-Native Prey In The Diet Of Three Sympatric Natricine Snakes, Emily E. Virgin, Richard B. King Apr 2019

What Does The Snake Eat? Breadth, Overlap, And Non-Native Prey In The Diet Of Three Sympatric Natricine Snakes, Emily E. Virgin, Richard B. King

Biology Faculty Publications

We investigated diet breadth and diet overlap in three sympatric snakes of similar body size: Dekay’s Brownsnakes (Storeria dekayi), Red-bellied Snakes (S. occipitomaculata), and sub-adult Common Gartersnakes (Thamnophis sirtalis), by examining recently consumed prey (n = 388) collected from wild-caught snakes (n = 263) in northern Illinois. Storeria occipitomaculata were dietary specialists, feeding nearly exclusively on slugs. Storeria dekayi fed predominately on slugs but also consumed snails and earthworms. Sub-adult T. sirtalis fed predominately on earthworms but also consumed frogs and small mammals. Diet overlap was extensive between Storeria species but relatively low between …

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Trait-Based Community Assembly Pattern Along A Forest Succession Gradient In A Seasonally Dry Tropical Forest, Suresh C. Subedi, Michael S. Ross, Jay P. Sah, Jed Redwine, Christopher Baraloto Apr 2019

Trait-Based Community Assembly Pattern Along A Forest Succession Gradient In A Seasonally Dry Tropical Forest, Suresh C. Subedi, Michael S. Ross, Jay P. Sah, Jed Redwine, Christopher Baraloto

Faculty Publications - Biological Sciences

We aimed to determine the important functional dimensions that may drive forest succession and community assembly patterns in dry tropical forests. We investigated whether there were patterns in specific functional strategies during succession in the dry tropical forests of the Florida Keys, whose unique physical setting includes nutrient-stressed, salt-stressed, and water-limited environments. The study, which focused on ten traits, determined the leading trait dimensions by which species differentiate from one another in the study area. The general patterns of trait covariation at individual sites and among species were analyzed using principal component analysis. Trait niche overlap indices were calculated for …

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Multispecies Character Displacement In Mexican Poeciliopsis Fishes, Andrea J. Roth Apr 2019

Multispecies Character Displacement In Mexican Poeciliopsis Fishes, Andrea J. Roth

Theses and Dissertations

Competition has long been recognized as a central force in shaping evolution, particularly through character displacement. Yet research on character displacement is biased as it has focused almost exclusively on pairs of interacting species while ignoring multispecies interactions. Unfortunately, communities are seldom so simple that only pairs of species interact, and it is not clear if inferences from pairwise interactions are sufficient to explain patterns in nature. A more realistic approach is to ask how traits evolve when multiple species interact. Here I explore the importance of multispecies competitive interactions on trait evolution in four congeneric species of livebearing fishes …

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Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff Jan 2019

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff

Biological Sciences Faculty Publications

A mathematical model for a two-pathogen, one-tick, one-host system is presented and explored. The goal of this model is to determine how long an invading pathogen persists within a tick population in which a resident pathogen is already established. The numerical simulations of the model demonstrate the parameter ranges that allow for coexistence of the two pathogens. Sensitivity analysis highlights the importance of vector-borne, tick-to-host, transmission rates on the invasion reproductive number and persistence of the pathogens over time. The model is then applied to a case study based on a reclaimed swampland field site in southeastern Virginia using field …

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Facilitative And Competitive Tradeoffs Between Morella Cerifera Seedlings And Coastal Grasses, Michael N. Sinclair Jan 2019

Facilitative And Competitive Tradeoffs Between Morella Cerifera Seedlings And Coastal Grasses, Michael N. Sinclair

Theses and Dissertations

Morella cerifera is a rapidly expanding native shrub on the Virginia barrier islands which displaces other native coastal species and may interrupt normal sediment dynamics. Barrier islands are considered stressful environments with low nutrients, high solar load, and frequent drought and salt exposure; facilitation often dominates in stressful environments according to the Stress Gradient Hypothesis. The objective of this project was to understand the importance of species interactions with grasses on the growth and physiology of M. cerifera at the seedling life stage through both field and lab experiments. Grasses provided ~1.3°C insulation to shrubs during winter freeze events and …

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A Comprehensive Synthesis Of Liana Removal Experiments In Tropical Forests, Sergio Estrada-Villegas, Stefan A. Schnitzer Sep 2018

A Comprehensive Synthesis Of Liana Removal Experiments In Tropical Forests, Sergio Estrada-Villegas, Stefan A. Schnitzer

Biological Sciences Faculty Research and Publications

Lianas are a quintessential feature of tropical forests and are often perceived as being poorly studied. However, liana removal studies may be one of the most common experimental manipulations in tropical forest ecology. In this review, we synthesize data from 64 tropical liana removal experiments conducted over the past 90 yr. We explore the direction and magnitude of the effects of lianas on tree establishment, growth, survival, reproduction, biomass accretion, and plant and animal diversity in ecological and forestry studies. We discuss the geographical biases of liana removal studies and compare the various methods used to manipulate lianas. Overall, we …

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