Population Biology Commons^™

An Integrative Approach To Managing A Species Of Conservation Concern: Resource Selection, Spatial Ecology, And Population Genetics Of The Green Salamander (Aneides Aeneus), Megan Novak

All Dissertations

The relationship between wildlife and the environment they inhabit is dependent on both spatial and temporal scales. It is therefore crucial that biological investigations account for ecological scale when analyzing patterns and processes established, particularly when such investigations inform conservation management plans. This dissertation provides extensive insight into the conservation biology of the green salamander (Aneides aeneus), a critically imperiled species in South Carolina. The green salamander is a species that exists in a patchy network of rock outcrops within mountainous forest landscapes, and most studies on habitat suitability for green salamanders have been conducted on the macrohabitat, …

Population Abundance And Growth Of Elk (Cervus Canadensis) In Western North Carolina, Jessica Braunstein

Doctoral Dissertations

In an effort to restore extirpated elk to their previous range, 52 elk were reintroduced to Great Smoky Mountains National Park (GRSM) in North Carolina during 2001 and 2002. Since their reintroduction, elk numbers have increased and their range has extended beyond GRSM boundaries. My primary research objectives included estimating population abundance, apparent survival, per capita recruitment, and population growth rate of elk in North Carolina. I used spatially explicit capture-recapture (SECR) models based on fecal DNA to identify individual elk and estimate population abundance and growth in the region. Technicians and I walked a series of transects throughout the …

Unraveling A Paradox Of Habitat Relationships: Scale-Dependent Drivers Of Temporal Occupancy-Abundance Relationships In A Cooperatively Breeding Bird, Natasha D.G. Hagemeyer, Mario B. Pesendorfer, Walter D. Koenig, Eric L. Walters

Biological Sciences Faculty Publications

Context Spatial occupancy and local abundance of species often positively covary, but the mechanisms driving this widespread relationship are poorly understood. Resource dynamics and habitat changes have been suggested as potential drivers, but long-term studies relating them to abundance and occupancy are rare. In this 34-year study of acorn woodpeckers (Melanerpes formicivorus), a cooperatively breeding species, we observed a paradoxical response to changes in habitat composition: despite a reduction in the availability of high-quality breeding habitat, the population increased considerably.

Objectives We investigated the role of annual variation in food availability and long-term changes in habitat composition as predictors …

Quantifying Antarctic Krill Connectivity Across The West Antarctic Peninsula And Its Role In Large-Scale Pygoscelis Penguin Population Dynamics, Katherine L. Gallagher, Michael S. Dinniman, Heather J. Lynch

CCPO Publications

Antarctic krill (Euphausia superba) are considered a keystone species for higher trophic level predators along the West Antarctic Peninsula (WAP) during the austral summer. The connectivity of krill may play a critical role in predator biogeography, especially for central-place foragers such as the Pygoscelis spp. penguins that breed along the WAP during the austral summer. Antarctic krill are also heavily fished commercially; therefore, understanding population connectivity of krill is critical to effective management. Here, we used a physical ocean model to examine adult krill connectivity in this region using simulated krill with realistic diel vertical migration behaviors across …

A Simulation Model Of Sustained-Yield Harvest For Northern Bobwhite In South Texas, Joseph P. Sands, Stephen J. Demaso, Fidel Hernández, Leonard A. Brennan, Matthew J. Schnupp, Trent W. Teinert, Dale Rollins, Robert M. Perez

National Quail Symposium Proceedings

Recommended sustainable harvest rates for northern bobwhite (Colinus virginianus) vary greatly and range from 25% to 70% of the prehunt population. Because northern bobwhite populations have declined across their geographic range, determining sustainable harvest levels is critical for effective management. Our objectives were to use simulation modeling to identify sustainable rates of bobwhite harvest, probability of population persistence, and minimum viable population estimates. We also conducted a sensitivity analysis to evaluate the impacts of harvest on northern bobwhite populations in Texas, USA. We constructed a simulation model using Program STELLA 9.0 for a hypothetical northern bobwhite population on …

Ocean Quahog (Arctica Islandica) Population Dynamics: Sex-Based Demographics And Regional Comparisons In The Northwest Atlantic, Kathleen M. Hemeon

Dissertations

Arctica islandica (ocean quahog) is the longest-lived bivalve on Earth. Individuals on the deep continental shelf of the Mid-Atlantic (US) can survive for centuries, and when found in the colder, boreal waters of Iceland, ages over 500 years can be reached. The ocean quahog is important in the US, yet very little is known about the resiliency of the ocean quahog stock to fishing activity, and ocean quahog recruitment patterns over time. To quantify and constrain age-reader error prior to age analysis, a triple-method error protocol was developed for A. islandica that included age-reader bias, precision, and error frequency. The …

Evaluating Relative Abundance, Fish Length, And Marine Protected Area Effectiveness For Four Key Rocky Reef Species Along The Northern Californian Coast, Leon Davis

Cal Poly Humboldt theses and projects

Marine protected areas (MPAs) were created with the purpose of helping conserve and restore diminished populations of marine organisms. Measuring the effectiveness of MPAs requires long-term monitoring, investigating the abundance and size distributions of the species that utilize the conservation areas, and comparing the results to neighboring reference sites that are not currently protected. In this study, observations from long-term MPA monitoring in northern California (2010-2019) were modeled with substrate, oceanographic, spatial, temporal, and body size variables to describe the variability in abundance and size of three fish groups: Black rockfish (Sebastes melanops), the Blue rockfish group (comprised …

Evidence For Irruptive Fluctuation In Axis Deer Of Hawai‘I, Steven C. Hess, Jonathan Sprague, Jacob Muise

USDA Wildlife Services: Staff Publications

Axis deer on the Hawaiian Islands of Maui, Lāna‘i, and Moloka‘i simultaneously experienced one of the most dramatic population crashes on record in 2020-2021, which coincided with extended drought conditions and prompted an emergency declaration for these islands. This phenomenon has been anecdotally documented during previous drought events in 2011-2012, but never formally studied. Newspaper articles document abundant deer becoming a nuisance to agriculture and natural resources, and then experiencing high mortality during droughts. This phenomenon fits Caughley’s (1970) operational definition of eruptive (sic) fluctuation “…as an increase in numbers over at least two generations, followed by a marked decline.” …

Factors Influencing Brook Trout Population Dynamics And Resilience In Central Appalachian Headwater Streams, Christopher W. Schwinghamer

Graduate Theses, Dissertations, and Problem Reports

Central Appalachia has a unique history of human perturbation due largely to its historical economic reliance on extractive industry and timber harvest. Legacy impacts from these historic disturbances along with contemporary stressors in the form of continued industry, changing climates, altered land use, habitat fragmentation, and introduced species can present great threats to the region’s aquatic ecosystems. Brook Trout Salvelinus fontinalis are a species that has recreational and economic importance to the communities of central Appalachia but declines in size and abundance have been observed. Given the disturbances that threaten Brook Trout populations, understanding how their populations will respond to …

Invader Removal Triggers Competitive Release In A Threatened Avian Predator, J. David Wiens, Katie M. Dugger, J. Mark Higley, Damon B. Lesmeister, Alan B. Franklin, Keith A. Hamm, Gary C. White, Krista E. Dilione, David C. Simon, Robin R. Bown, Peter C. Carlson, Charles B. Yackulic, James D. Nichols, James E. Hines, Raymond J. Davis, David W. Lamphear, Christopher Mccafferty, Trent L. Mcdonald, Stan G. Sovern

USDA Wildlife Services: Staff Publications

Changes in the distribution and abundance of invasive species can have far-reaching ecological consequences. Programs to control invaders are common but gauging the effectiveness of such programs using carefully controlled, large-scale field experiments is rare, especially at higher trophic levels. Experimental manipulations coupled with long-term demographic monitoring can reveal the mechanistic underpinnings of interspecific competition among apex predators and suggest mitigation options for invasive species. We used a large-scale before-after control-impact removal experiment to investigate the effects of an invasive competitor, the barred owl (Strix varia), on the population dynamics of an iconic old-forest native species, the northern spotted owl …

Trait Variation And Long-Term Population Dynamics Of The Invasive Alliaria Petiolata (Garlic Mustard) Across Three Microhabitats In Its Invaded Range, Laura Hancock

Masters Theses

Long-term population dynamics across heterogeneous environments can be a major factor in determining species’ ability to expand their ranges and persist in novel environments. Whether and how the relative performance of populations in different microsites over time impacts invasion into new microsites is poorly understood. Though largely restricted to disturbed semi-shaded microhabitats in its home range, the invasive herb Alliaria petiolata (garlic mustard) successfully invades intact forest understories – a novel microhabitat – in its introduced range, where it is known to impact above and below ground community composition. To test the hypothesis that source-sink metapopulation dynamics may be promoting …

Evaluating Common Raven Take For Greater Sage-Grouse In Oregon’S Baker County Priority Conservation Area And Great Basin Region, Frank F. Rivera-Milán, Peter S. Coates, Jacqueline B. Cupples, Michael Green, Patrick K. Devers

Human–Wildlife Interactions

The common raven (Corvus corax; raven) is a nest predator of species of conservation concern, such as the greater sage-grouse (Centrocercus urophasianus). Reducing raven abundance by take requires authorization under the Migratory Bird Treaty Act. To support U.S. Fish and Wildlife Service’s take decisions (e.g., those that authorize killing a specified proportion or number of individuals annually in a defined area), including the most recent one for Oregon’s Baker County Priority Area for Conservation (PAC), we modeled raven population dynamics under hypothetical scenarios with take rates ranging from below to above the maximum sustained yield (MSY; …

Spectral Properties Of A Non-Compact Operator In Ecology, Matthew Reichenbach

Department of Mathematics: Dissertations, Theses, and Student Research

Ecologists have used integral projection models (IPMs) to study fish and other animals which continue to grow throughout their lives. Such animals cannot shrink, since they have bony skeletons; a mathematical consequence of this is that the kernel of the integral projection operator T is unbounded, and the operator is not compact. A priori, it is unclear whether these IPMs have an asymptotic growth rate λ, or a stable-stage distribution ψ. In the case of a compact operator, these quantities are its spectral radius and the associated eigenvector, respectively. Under biologically reasonable assumptions, we prove that the non-compact operators in …

Population Demographics Of Silver Carp Hypophthalmichthys Molitrix In Kentucky Lake, Allison M. Lebeda

Murray State Theses and Dissertations

Invasive species continue to threaten aquatic ecosystems in the United States. Silver Carp Hypophthalmichthys molitrix have successfully infiltrated much of the Mississippi River Basin, including Kentucky Lake – a large reservoir located on the Tennessee River in Western Kentucky. Although Silver Carp have been present in Kentucky Lake for at least a decade, until recently, very little was known about the population, how often successful reproduction is occurring, or the environmental conditions that facilitate strong year-classes. Hence, it is difficult for managers to predict the potential impact of Silver Carp on native species. Silver Carp were collected from Kentucky Lake …

Marine-Derived Nutrient Cycling In The St. Croix River, Maine, Betsy Barber

Electronic Theses and Dissertations

Anadromous species can boost freshwater productivity through nutrient subsidies. Along the Maine coast of the northeast United States, several alewife populations are recovering after freshwater connectivity is restored. Iteroparity in this part of their range may reduce their role as nutrient subsidies. Stable isotope analysis was used to detect marine-derived nutrient input. Spatial and temporal trends were characterized in the St. Croix as a baseline before alewife recovery, and nutrient-diffusing substrates indicated nutrient co-limitation. A reference watershed was used to compare nutrient dynamics when alewives were present versus absent. Results indicated isotope shifts within particular functional feeding groups, but not …

Big Brains Stabilize Populations And Facilitate Colonization Of Variable Habitats In Birds, Trevor S. Fristoe, Andrew N. Iwaniuk, Carlos A. Botero

Biology Faculty Publications & Presentations

The cognitive buffer hypothesis posits that environmental variability can be a major driver of the evolution of cognition because an enhanced ability to produce flexible behavioural responses facilitates coping with the unexpected. Although comparative evidence supports different aspects of this hypothesis, a direct connection between cognition and the ability to survive a variable and unpredictable environment has yet to be demonstrated. Here, we use complementary demographic and evolutionary analyses to show that among birds, the mechanistic premise of this hypothesis is well supported but the implied direction of causality is not. Specifically, we show that although population dynamics are more …

Life-Shortening Wolbachia Infection Reduces Population Growth Of Aedes Aegypti, Eunho Suh, David R. Mercer, Stephen L. Dobson

Entomology Faculty Publications

Wolbachia bacteria are being introduced into natural populations of vector mosquitoes, with the goal of reducing the transmission of human diseases such as Zika and dengue fever. The successful establishment of Wolbachia infection is largely dependent on the effects of Wolbachia infection to host fitness, but the effects of Wolbachia infection on the individual life-history traits of immature mosquitoes can vary. Here, the effects of life-shortening Wolbachia (wMelPop) on population growth of infected individuals were evaluated by measuring larval survival, developmental time and adult size of Aedes aegypti in intra- (infected or uninfected only) and inter-group (mixed with …

Survival, Harvest, And Drumming Ecology Of Ruffed Grouse In Central Maine, Usa, Samantha Davis

Electronic Theses and Dissertations

Understanding population dynamics and how species interact with their environment are important components for conservation and management. Ruffed grouse (Bonasa umbellus) are a widely distributed and common game bird in North America and are a considered an important economic and cultural icon in Maine. Although they are a well-studied species, there has been little research focused on ruffed grouse population dynamics and habitat relationships in Maine. My thesis aims to improve this knowledge gap by focusing on research related to survival and harvest of ruffed grouse, as well as male ruffed grouse resource selection at breeding display sites. Ruffed grouse …

Biology, Molecular Systematics, Population Dynamics And Control Of A Stem Gall Wasp, Zapatella Davisae (Hymenoptera: Cynipidae), Monica Davis

Doctoral Dissertations

Gall wasps are phytophagous insects that often go unnoticed, however, when they are released from their natural enemies, they have the capacity to outbreak and cause extensive foliar damage. One such outbreaking pest, Zapatella davisae, causes significant damage and mortality to black oak, Quercus velutina. In recent years, black oak decline has been documented in Long Island, New York and coastal New England. Little is known about the lifecycle, distribution or population dynamics of Zapatella davisae and the taxonomy of the species is still unclear. My first study described the biology and distribution of Z. davisae. Zapatella …

Measuring Fertilization In Populations Of Sea Scallop (Placopecten Magellanicus): Developing And Testing Methods In The Laboratory And Field, Skylar Bayer

Electronic Theses and Dissertations

Most marine organisms are broadcast spawners, releasing their sperm and eggs into the water column. Methods of measuring in situ fertilization have proven successful with a few model species, which are reviewed in my introductory chapter. However, many commercially exploited species, such as the sea scallop Placopecten magellanicus, have been neglected. Sea scallop populations have greatly increased from fishing closures, but the mechanism behind this response is uncertain, particularly in regard to fertilization. In this dissertation I developed a methodology of measuring fertilization success and spawning events of P. magellanicus, tested it in laboratory and field settings, and …

Patterns In Greater Sage-Grouse Population Dynamics Correspond With Public Grazing Records At Broad Scales, Adrian P. Monroe, Cameron L. Aldridge, Timothy J. Assal, Kari E. Veblen, David A. Pyke, Michael L. Casazza

Wildland Resources Faculty Publications

Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) …

Population Dynamics Of The Cotton Rat In Southeastern Virginia, Robert K. Rose, Heather Green Salamone

Virginia Journal of Science

Abstract

We used monthly live trapping for 2.5 years to evaluate the life-history features of the most common small mammal, Sigmodon hispidus (hispid cotton rat), in an old field at its northern limit of distribution on the Atlantic coast. Peak densities, achieved in late autumn or early winter, were among the highest recorded for the species and were more typical of marginal populations rather than of central ones. Unlike some other marginal populations, hispid cotton rats in eastern Virginia did not lose significant body mass over the winter (when few juveniles were present) and survival in winter was not significantly …

Fishery And Population Dynamics Of Mississippi’S Spotted Seatrout, David Arthur Dippold

Master's Theses

Spotted Seatrout (Cynoscion nebulosus) is the most popular recreational inshore fishery in Mississippi coastal waters. Because of the popularity of Spotted Seatrout in Mississippi as a recreational target and the magnitude of harvest, quantitative approaches to describe the population and fishery dynamics of the Mississippi stock are needed to continue the sustainability of the stock. Quantitative approaches to describing stock dynamics are useful because they can help describe population characteristics, assess the current status of the stock, and be used to evaluate alternative management strategies. In this thesis, I use a suite of quantitative methods to describe, evaluate, …

Effects Of Mountaintop Removal Mining On Population Dynamics Of Stream Salamanders, Sara B. Freytag

Theses and Dissertations--Forestry and Natural Resources

Mountaintop removal mining (MTR) is a notorious stressor of stream ecosystems in the Central Appalachians. Valley fills (VF) lead to reduced occupancy, abundance, and species richness of stream salamanders. Multiple factors may be responsible for these reductions, but specifically habitat fragmentation and degradation may reduce colonization rates and increase local extinction rates. From 2013-2015, repeated counts of salamanders were conducted in stream reaches impacted by MTR/VF and compared to counts in reference reaches to answer the question: do stream salamander population dynamics differ between stream reaches impacted by MTR/VF and reference stream reaches? I also investigated dynamics of stream habitat …

Host Densities And Parasitism Rates In A Forest Defoliator Across A Rural-Urban Landscape, Abigail J. Nelson

Theses and Dissertations

Fall cankerworm (FCW) outbreaks have recently increased in frequency and intensity in the mid-Atlantic region of the United States, especially around cities of Charlotte, NC and Richmond, VA. This study evaluated the effects of two landscape features associated with urbanization, impervious surface and forest cover, on population patterns of FCW and its parasitoids across eastern Virginia. Forest cover was positively related to parasitism rates while impervious surface was positively related to FCW abundance, suggesting that FCW outbreaks may be amplified in urban areas. FCW abundance declined over the two-year period of this study, but parasitism rate increased at most sites. …

An Agent-Based Modeling Approach To Determine Winter Survival Rates Of American Robins And Eastern Bluebirds, Samuel Iselin, Shannon Segin, Alex Capaldi

Alex Capaldi

Density-Dependent Survival In The Larval Stage Of An Invasive Insect: Dispersal Vs. Predation, Adam A. Pepi

Masters Theses

1. The success of invasive species is often thought to be due to release from natural enemies. This hypothesis relies on the assumption that species are regulated by top-down forces in their native range and implies that species are likely to be regulated by bottom-up forces in the invasive range. Neither of these assumptions has been consistently supported with insects, a group which include many highly destructive invasive pest species.

2. Winter moth (Operophtera brumata) is an invasive defoliator in North America that appears to be regulated by mortality in the larval stage in its invasive range. To …

Spatiotemporal Variation In Flow-Dependent Recruitment Of Long-Lived Riverine Fish: Model Development And Evaluation, Daisuke Goto, Martin J. Hamel, Jeremy J. Hammen, Mathew L. Rugg, Mark A. Pegg, Valery E. Forbes

School of Biological Sciences: Faculty Publications

Abstract Natural flow regimes can play a major role as an overarching ecosystem driver in reproduction and recruitment of riverine fishes. Human needs for freshwater however have altered hydrology of many riverine systems worldwide, threatening fish population sustainability. To understand and predict how spatiotemporal dynamics of flow regimes influence reproductive and recruitment variability, and ultimately population sustainability of shovelnose sturgeon (Scaphirhynchus platorynchus), we develop a spatially explicit (1D) individual-based population model that mechanistically (via energetics-based processes) simulates daily activities (dispersal, spawning, foraging, growth, and survival). With field observations of sturgeon and habitat conditions in a major tributary of …

Hybridization As A Stimulus For Adaptation To A Novel Environment, Dylan Robert Dittrich-Reed

Doctoral Dissertations

Understanding processes contributing to the origin of novelty, including ecological transitions in resource or habitat use, is fundamental to evolutionary biology. Early geneticists speculated about the sudden appearance of new species via special macromutations, epitomized by Goldschmidt’s infamous “hopeful monster”. Transgressive segregation during hybridization is a more plausible mechanism for producing “monstrous” phenotypes beyond the range of parental populations. Transgressive hybrid phenotypes can be products of epistatic interactions or additive effects of multiple recombined loci. However, the importance of hybridization in the origin of novelty is contested because we do not know how often hybridization enhances the probability of an …

Collaborative Research: Land-Use Practices And Persistence Of Amphibian Populations., Malcolm L. Hunter Jr.

University of Maine Office of Research Administration: Grant Reports

Over the past 200 years, conversion of land for agricultural use, industrial development, and urban sprawl has drastically reduced natural habitat for many species and is considered the most serious threat to biological diversity. Fragmentation divides once continuous natural habitats into smaller pieces that are often separated by areas unsuitable to sustain viable populations. The goal of the proposed research is to understand how important local population and metapopulation processes are altered by fragmentation of natural habitats in a model system of pond-breeding amphibians. The primary objectives of the proposed study are to experimentally compare demographic and behavioral responses of …