Life Sciences Commons^™

Salinity Tolerance Of Gambusia Affinis, Sarah Rubelowsky

Honors Theses

Developmental plasticity refers to changes during development as a result of environmental contributions. Salinity is a varying environmental condition in freshwater and estuarine habitats that can mediate developmental plasticity in Gambusia affinis, which can increase their tolerances as an invasive species. For my study, estuarine and freshwater populations of Gambusia affinis were sampled in March of 2017 using dip nets. Both populations were then brought back to the laboratory where pregnant females were acclimated to three different salinities (0‰, 15‰, 25‰) until they gave birth. I predicted that the estuarine population of Gambusia affinis would have a greater salinity tolerance …

Evaluating The Ecological Status Of The Introduced Nile Monitor (Varanus Niloticus) In Florida: Forecasting Presence And Population Expansion Using Computational Geographic Information Systems, Noah G. Cohen

HCNSO Student Theses and Dissertations

The Nile monitor (Varanus niloticus) is a large, carnivorous lizard that has become a notorious invasive species in Florida, USA. Initially released in the 1980s from the pet trade, the species has since established at least three breeding populations and spread throughout much of southern Florida. While current control efforts have failed to eradicate V. niloticus, it is important to attain a better understanding of its invasive dynamics to guide and inform better control strategies. In this study, available georeferenced records of V. niloticus in Florida were compiled and linked to a habitat classification map to evaluate ecotype preferences. Factored …

European Starlings, H. Jeffrey Homan, Ron J. Johnson, James R. Thiele, George M. Linz

Wildlife Damage Management Technical Series

European starlings (Sturnus vulgaris, Figure 1) are an invasive species in the United States. The first recorded release of the birds was in 1890 in New York City’s Central Park. Because starlings easily adapt to a variety of habitats, nest sites and food sources, the birds spread quickly across the country. Today, there are about 150 million starlings in North America. Conflicts between people and starlings occur mostly in agricultural settings. Conflicts can occur during winter in urban and suburban environments, especially in business districts.

Starlings damage apples, blueberries, cherries, figs, grapes, peaches, and strawberries. Besides causing direct losses from …

A Window Of Opportunity: Subdominant Predators Can Use Suboptimal Prey, Kelly A. Jackson, Joshua S. Mccord, Jennifer A. White

Entomology Faculty Publications

Introduced species have been linked to declines of native species through mechanisms including intraguild predation and exploitative competition. However, coexistence among species may be promoted by niche partitioning if native species can use resources that the invasive species cannot. Previous research has shown that some strains of the aphid Aphis craccivora are toxic to a competitively dominant invasive lady beetle, Harmonia axyridis. Our objective was to investigate whether these aphids might be an exploitable resource for other, subdominant, lady beetle species. We compared larval development rate, survival, and adult weight of five lady beetle species in no-choice experiments with …

Ecology, Evolution, And Sexual Selection In The Invasive, Globally Distributed Small Indian Mongoose (Urva Auropunctata), M. Aaron Owen

Dissertations, Theses, and Capstone Projects

Introduced species provide rare opportunities to test evolutionary hypotheses in situ by creating so-called natural experiments. Natural experiments are situations in nature that resemble laboratory studies by allowing for comparisons of a “control” group (i.e., a species’ native range) with “experimental” groups (i.e., a species’ introduced range). In particular, introduced animals allow us to investigate evolutionary dynamics in complex, long-lived organisms in ways that would otherwise be impossible in a laboratory setting. One such introduced animal is the small Indian mongoose (Urva auropunctata, formerly Herpestes auropunctatus). Native to South Asia, the small Indian mongoose’s introduction to more …

A Spiny Water Flea Invasion And Effects On The Zooplankton Community In Southern Green Bay, Lake Michigan, Casey Ann Merkle

Lawrence University Honors Projects

The spiny water flea (Bythotrephes longimanus) is an invertebrate aquatic invasive species (AIS) in the Great Lakes that competes with native fish species for zooplankton, perhaps contributing to a decline of fish populations or changes in zooplankton communities in Lake Michigan. Bythotrephes produce two types of eggs, immediately hatching versus resting eggs which are tolerant to harsh conditions and allow for rapid dispersal. We determined Bythotrephes population density and population dynamics in Green Bay during the summer months of 2015 and 2016. Population dynamics were similar at both sites in Green Bay in each year, with peak population …

Influence Of Stream Permanence, Predation, And Invasive Species On Crayfish In The Ozark Highlands With An Emphasis On Species Of Greatest Conservation Need (Orconectes Marchandi, Orconectes Eupunctus And Cambarus Hubbsi), Allyson Noelle Yarra

Graduate Theses and Dissertations

Due to the ecological importance of crayfish and the increasing vulnerability of freshwater systems due to habitat loss, invasive species, and hydrologic alteration, understanding crayfish-environment relationships is crucial in the context of aquatic species conservation. I sought to examine the influence of hydrologic variation among intermittent and permanent streams on crayfish occupancy, abundance, predation risk, and potential vulnerability to invasive species effects. I conducted crayfish and environmental data sampling during two consecutive summers across 20 Ozark streams of differing permanence levels (10 intermittent, 10 permanent). In these same streams, I conducted fish and scat surveys over the course of four …

Ecological Importance Of Invader Source Population And Disturbance In Aquatic Invasions, Nicole Elizabeth Graham

Graduate Theses and Dissertations

Invasive species are a global problem and their effects on recipient ecosystems may be mediated by disturbance and intraspecific variation. Crayfish can substantially influence stream structure and function, and invasive crayfish often have differential impacts than native crayfish in aquatic ecosystems. Since species traits often vary across a distribution, it is possible that invasive crayfish from different source populations may have distinct impacts on recipient ecosystem structure and function. In the Ozark Highlands of Arkansas and Missouri, USA, invasive O. neglectus (the Ringed Crayfish) may be leading to the displacement of native O. eupunctus (the Coldwater Crayfish). The objective of …

Predicting The Impact Of A Northern Pike (Esox Lucius) Invasion On Endangered June Sucker (Chasmistes Liorus) And Sport Fishes In Utah Lake, Ut, Jamie Reynolds

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Invasive species introductions are associated with negative economic and environmental impacts, including reductions in native species populations. Successful invasive species populations often grow rapidly and a new food web structure is established. The ability of invasive species to outcompete and prey upon native species are two characteristics that make them a leading cause of fish extinctions in North America.

Northern pike (Esox lucius; hereafter pike) are voracious ambush top predators \native to the upper Midwest and Mid-Atlantic regions of the lower 48 United States, Alaska, and southern Canada. Pike have been spreading across the Intermountain West and Pacific …

Mechanical Harvesting Effectively Controls Young Typha Spp. Invasion And Unmanned Aerial Vehicle Data Enhances Post-Treatment Monitoring, Shane Lishawa, Brendan D. Carson, Jodi S. Brandt, Jason M. Tallant, Nicholas J. Reo, Dennis A. Albert, Andrew M. Monks, Joseph M. Lautenbach

School of Environmental Sustainability: Faculty Publications and Other Works

The ecological impacts of invasive plants increase dramatically with time since invasion. Targeting young populations for treatment is therefore an economically and ecologically effective management approach, especially when linked to post-treatment monitoring to evaluate the efficacy of management. However, collecting detailed field-based post-treatment data is prohibitively expensive, typically resulting in inadequate documentation of the ecological effects of invasive plant management. Alternative approaches, such as remote detection with unmanned aerial vehicles (UAV), provide an opportunity to advance the science and practice of restoration ecology. In this study, we sought to determine the plant community response to different mechanical removal treatments to …

Biotic And Abiotic Factors Predicting The Global Distribution And Population Density Of An Invasive Large Mammal, Jesse S. Lewis, Mathew L. Farnsworth, Christopher L. Burdett, David M. Theobald, Miranda Gray, Ryan S. Miller

Other Publications in Wildlife Management

Biotic and abiotic factors are increasingly acknowledged to synergistically shape broad-scale species distributions. However, the relative importance of biotic and abiotic factors in predicting species distributions is unclear. In particular, biotic factors, such as predation and vegetation, including those resulting from anthropogenic land-use change, are underrepresented in species distribution modeling, but could improve model predictions. Using generalized linear models and model selection techniques, we used 129 estimates of population density of wild pigs (Sus scrofa) from 5 continents to evaluate the relative importance, magnitude, and direction of biotic and abiotic factors in predicting population density of an invasive large mammal …

Phenotypic Plasticity Of Native And Invasive Cool-Season Grasses In Response To Frequency Of Moisture Availability, Ming-Yu Stephens

Electronic Theses and Dissertations

Phenotypic plasticity, the ability of an individual to alter its growth in response to environmental conditions, is an attribute that is considered a likely invader attribute, as it provides the opportunity to expand its ecological niche breadth. Adaptive phenotypic plasticity can affect not only the ability to establish in a new environment, but also the ability to outperform the existing vegetation over time. Bromus inermis (smooth brome) and Poa pratensis (Kentucky bluegrass) are invasive species in tall- and mixed-grass prairie ecosystems. The objectives of this two-part study were to quantify the adaptive plasticity of biomass accumulation and tiller production in …

The Effect Of Site Characteristics On The Reproductive Output Of Lesser Celandine (Ranunculus Ficaria), Justin P. Kermack

ETD Archive

Ranunculus ficaria L., an ephemeral perennial invasive plant brought over from Europe, is becoming widespread throughout the Northeastern United States. This herbaceous buttercup is able to create extensive dense mats that limit native species growth. Taking advantage of an early growing season and rapid reproduction rates, this species can create dense monocultures, which threatens native communities and ecosystems. Elimination of native spring ephemerals results in decreased biodiversity. A better understanding of how R. ficaria responds to site characteristics is needed to prioritize management efforts toward high-risk sites.

Ranunculus ficaria abundance and reproductive output (seed, bulbil and tuber production rates) were …

Assessing The Genetic Status And Factors Leading To The Decline Of The Roanoke Bass (Ambloplites Cavifrons), Jackman C. Eschenroeder

Electronic Theses and Dissertations

Although numerous factors have led to the staggering declines in freshwater biodiversity throughout the United States and the world, habitat alteration and introduced species pose some of the greatest challenges to conservation efforts. Learning more about how these two factors lead to the decline of an endemic organism could help prevent the future loss of unique species and the premature conclusion of evolutionary trajectories. Roanoke bass (Ambloplites cavifrons) is a sport fish endemic to portions of the Roanoke, Chowan, Tar, and Neuse river basins of North Carolina and Virginia. This species has been in decline for many years, …

Determining The Reproductive Patterns Of The Titan Acorn Barnacle (Megabalanus Coccopoma) In Its Introduced Range, Isabel L. Moran Ms.

Honors College Theses

Invasive species are a significant conservation concern given their contribution to native species decline. The barnacle, Megabalanus coccopoma, is a common invasive species in tropical and subtropical regions of both the Pacific and Atlantic oceans. Little is known about the life history and ecology of M. coccopoma, and data on reproductive biology could provide valuable insight into its propensity to establish introduced populations. Most species of barnacle (including M. coccopoma) are hermaphroditic, but self-fertilization is rare in species studied to date. A recent genetic study of introduced M. coccopoma populations in the southeastern US showed high levels of …