Ecology and Evolutionary Biology Commons^™

Fishery Interaction Modeling Of Cetacean Bycatch In The California Drift Gillnet Fishery To Inform A Dynamic Ocean Management Tool, Nicholas B. Sisson

Biological Sciences Theses & Dissertations

Understanding the drivers that lead to interaction between target species in a fishery and marine mammals is a critical aspect in efforts to reduce bycatch. In the California drift gillnet fishery static management approaches and gear changes have reduced bycatch but neither measure ascertains the underlying dynamics causing bycatch events. To avoid further potentially drastic measures such as hard caps, dynamic management approaches that consider the scales relevant to physical dynamics, animal movement and human use could be implemented. A key component to this approach is determining the factors that lead to fisheries interactions. Using 25 years (1990-2014) of National …

Marine Reserves Promote Coral Reef Resilience By Mitigating Human Impacts Through The Restoration Of Parrotfish Populations, Increasing Their Reproductive Output And Seeding Neighboring Overfished Reefs, Brian L. Stockwell

Biological Sciences Theses & Dissertations

Coral reefs are some of the most productive ecosystems on the planet, providing fisheries resources for over a billion people with billions of dollars in revenue from tourism for developing nations. Coral reefs are under threat from overfishing and water pollution, resulting in less productive algae dominated reefs. Marine reserves are widely expected to promote the resilience of reefs by protecting and increasing the abundance of herbivorous fishes that can graze on algae, therefore directly or indirectly preventing coral to algal phase shifts. However, the ability of marine reserves to mitigate human impacts, restore herbivorous fish populations and seed nearby …

Tracing The Genetic Footprints Of The Redbelly Yellowtail Fusilier, Caesio Cuning, Across Multiple Spatial And Evolutionary Scales, Amanda Susanne Ackiss

Biological Sciences Theses & Dissertations

Overfishing is one of the most pervasive threats to coral reef ecosystems, and management of these multi-species resources is hampered by limited species-specific population level information. The reefs in the western tropical Pacific Ocean, including the Coral Triangle, are the most bio-diverse in the world. Home to more than 400 million people, this region contains some of the most threatened coral reef ecosystems. Presented here is the first comprehensive analysis of the genetic structure of Caesio cuning, planktivorous fish inhabiting reefs in the Coral Triangle and western Pacific Ocean. Data from both classical Sanger and next-generation sequencing were analyzed …

Population Structure Of Lethrinus Lentjan (Lethrinidae, Percoidei) Across The South China Sea And The Philippines Is Detected With Lane-Affected Radseq Data, Ellen E. Biesack

Biological Sciences Theses & Dissertations

Southeast Asia includes the Coral Triangle, a marine biodiversity hotspot that supports important fishery resources experiencing varied threats. Patterns of speciation and population structure in the Coral Triangle have been examined to test hypotheses relating to the historical geologic processes that may have influenced this biodiversity phenomenon. This study investigates the genetic population structure of the Pink-ear Emperor Snapper, Lethrinus lentjan (Lacepède, 1802), across the Philippines and the South China Sea. The species is fished throughout the Coral Triangle by subsistence and commercial fishers and their landings have been in decline for several years, which could be indicative of depleted …

The Effect Of "Casitas" On Lobster Biology And Fishery Sustainability In The Bahamas, Lester George Gittens

Biological Sciences Theses & Dissertations

“Casitas” (artificial table-like structures) are a commercial fishing gear used to harvest Caribbean spiny lobster (Panulirus argus) in the Caribbean and in The Bahamas, where lobster is the most valuable fishery. Yet, casitas are largely unregulated in The Bahamas and they may threaten fishery sustainability through alteration of lobster growth, disease, or mortality rates and due to insufficient information concerning their number and location. Focusing on the lobster fishery in The Bahamas, my objectives were to: (1) investigate the mortality, growth, and susceptibility to disease of lobsters collected in casitas compared to wooden traps and those living in …

Determining Critical Internesting And Foraging Habitats For The Conservation Of Sea Turtles In Gabon, Africa Using Satellite Tracking And Stable Isotope Analysis, Tiffany M. Dawson

Biological Sciences Theses & Dissertations

Understanding the horizontal and vertical habitat of olive ridley sea turtles (Lepidochelys olivacea), a threatened species, is critical for determining regions of protection that may effectively reduce bycatch, the largest threat to this species. Satellite transmitters were used to determine the movement and dive behavior of 21 female olive ridley turtles tagged in Pongara National Park, Gabon during the 2012, 2013, and 2015 nesting seasons. A switching state space model was used to filter the tracking data and categorize the internesting and post-nesting movements. Gridded utilization distribution (UD) home range analysis of tracking data revealed that the entire core habitat …

Strawberries (Frag X Anan) Are Bigger When Native Mason Bees (Osmia Lignaria) Are Experimentally Added To Small Farms, Laura A. Campbell

Biological Sciences Theses & Dissertations

Agriculture is the cornerstone of our economy, and pollination plays a vital role in nearly all non-wind pollinated crops. Declining honey bee populations have caused a more diligent investigation into using solitary bees for crop pollination. The native, solitary Orchard Mason Bee has shown to successfully pollinate almonds and apples, but there has been little work conducted on their effectiveness as a low fruit crop pollinator. This study assesses their effectiveness as a small strawberry farm pollinator, and preferences for nesting materials. Mason bee cocoons and nest homes made with different materials (bamboo, Phragmites, or wood) were supplemented on …

Coarse Root Biomass And Architecture: Applications Of Ground Penetrating Radar, John Claude Bain

Biological Sciences Theses & Dissertations

The effectiveness of ground penetrating radar (GPR) to identify and quantify coarse roots was tested in a mixed-oak forest in Southeastern Virginia using experimental pits and locally excavated root segments. GPR was found to be highly dependent on low soil moisture levels as it is unable to differentiate root structures if they possess similar moisture content as their surrounding soil. Likewise, GPR was unable to identify simulated dead roots. This does not alter the effectiveness of GPR to measure living coarse root biomass, but does present the potential for underestimation of carbon storage in coarse root structures, as a dead …

Characterization Of Soundscapes In Shallow Water Habitats Of The Florida Keys (Usa) And Their Influence On The Settlement Of Larval Fish And Invertebrates, John R. Butler

Biological Sciences Theses & Dissertations

In recent decades, changes in climate and water quality in Florida Bay and the Florida Keys (FL, USA) caused expansive cyanobacteria blooms that in turn precipitated massive sponge die-offs that drastically altered sponge-dominated hard-bottom communities in south-central Florida Bay. This area served as a model system to explore the effect of ecosystem change and habitat restoration on underwater soundscapes and larval recruitment. I had four main objectives: (1) characterize the underwater soundscapes of three near-shore, benthic habitats: mangrove islands, seagrass meadows, and hard-bottom (Chapter 2); (2) quantify larval settlement within healthy, degraded, and restored hard-bottom areas to test whether habitat …

A Hitchhiker’S Guide To Invasion Biology: Describing The Ecological Mechanisms Underlying The Range Expansions Of Two Ixodid Tick Species, Robyn M. Nadolny

Biological Sciences Theses & Dissertations

Increasing incidence of many tick-borne diseases have been linked to recent expansions of tick species distributions. Many tick species are expanding their ranges because of anthropogenic changes in the landscape, shifting climatic variables, and increasing populations of suitable host species and tick habitat. Few empirical studies have been performed, however, investigating the ecological mechanisms underlying these range expansions. Ticks are parasitic organisms that disperse across landscape by hitchhiking on hosts, but must then survive in the environment for long periods of time between bloodmeals. Two species of ixodid tick, Ixodes affinis and Amblyomma maculatum, are simultaneously expanding their ranges throughout …

Naturalization Of Salt Marsh Restoration Sites In The Elizabeth River, Virginia, Assessed By Feeding Activity And Trophic Level Of Mummichogs (Fundulus Heteroclitus), Moriah Anne Good

Biological Sciences Theses & Dissertations

Recent efforts to mitigate environmental issues within the Southern Branch of the Elizabeth River, Virginia, designated a “Region of Concern” by the Chesapeake Bay Program, include several salt marsh restorations. By examining gut contents and stable isotopes values (δ13C and δ15N) from mummichogs (Fundulus heteroclitus), the functional equivalency of restored salt marshes compared to natural marshes was measured. In July 2013 I collected mummichogs from three restored and three reference salt marshes in the Southern Branch. Fish were collected for gut content analysis and were analyzed for stable isotopes (δ13C and δ15N).

I removed gut contents from 16 fish per …

The Effects Of Urbanization On Tick Parasitism Rates In Birds Of Southeastern Virginia, Erin Leigh Heller

Biological Sciences Theses & Dissertations

The coastal region of southeastern Virginia is one of the largest urban areas along one of North America’s migratory flyways. Because hundreds of avian species use this flyway, understanding factors affecting birds and their health is of paramount concern. Within this region, 14 species of ticks have been documented, all of which may serve as vectors of mammal (including human) pathogens. By sampling birds at sites of varying levels of urbanization within the coastal southeastern urban matrix, I studied the relationship between ticks and their avian hosts, and how this relationship varies seasonally. Mistnets were set-up at five permanent sites …

Perch Selection By Male Dragonflies (Odonata, Anisoptera) Related To Competitive Ability And Species Composition, Jessica L. Beard

Biological Sciences Theses & Dissertations

Males of many species of dragonflies (Odonata, Anisoptera) establish territories in aquatic habitats where they compete with other males for access to food and females. Territorial males typically perch on emergent vegetation and chase rival males who intrude into their territories. This dissertation research examined the role of male size in perch height selection, position on the perch, and competitive ability. Four hypotheses were tested: 1) Dragonfly species would vary by size and that territorial species would show sexual size dimorphism (SSD), 2) Perch height selection would be related to dragonfly size, 3) Position on the perch would be related …

Blue Carbon In Freshwater / Brackish Marshes On The Barrier Islands Of Virginia Aboveground Net Primary Productivity And Carbon Pools, Emily Caitlin Adams

Biological Sciences Theses & Dissertations

"Blue carbon" is a relatively new concept describing carbon distributed tidally and sequestered via net production within coastal ecosystems, including seagrass beds, mangrove forests, and salt-water marshes. These systems sequester carbon at least 10 times faster than terrestrial systems. Fresh to brackish wetlands that receive irregular tidal influence due to overwash and storm events have not been typically studied as blue carbon systems. My objective was to quantify carbon pools within four interdunal fresh to brackish marshes on Hog Island, Virginia to determine their blue carbon potential. Marshes 1 and 2 were farthest from the ocean, below and above a …

The Behavioral Causes Of Reproductive Skew In Cooperatively Polygynandrous Acorn Woodpeckers (Melanerpes Formicivorus), Anna C. Brownson

Biological Sciences Theses & Dissertations

Reproductive skew, the degree to which reproduction is shared among same-sex individuals in a social group, is a pattern affected by ecological conditions, sociality, cooperation, and the inter- and intrasexual behavior of individuals in complex animal societies. Transactional and compromise skew models assume that high skew is the product of dominance hierarchies among cobreeders, yet this has rarely been tested. Both model types fail to incorporate the decisions of more than two individuals, generally overlooking the effect of female behavior on male reproductive success in multi-male groups, and are ineffective at predicting skew in larger groups characterized by more than …

Blue Carbon In Coastal Freshwater/Brackish Marshes On The Barrier Islands Of Virginia: Belowground Carbon Dynamics, Nathan M. Sedghi

Biological Sciences Theses & Dissertations

Some coastal ecosystems sequester substantially more carbon (blue carbon) than land locked systems due to high net primary production and deposition associated with oceanic influences. Most blue carbon research has focused on mangroves, seagrass beds, and salt marshes. Studies on blue carbon potential of coastal freshwater marshes are less common. Barrier islands frequently flood, with seawater reaching interior ecosystems. I examined brackish/freshwater marshes on Virginia barrier islands for possible roles as blue carbon systems. I studied four interior marshes on Hog Island, which varied in proximity to a direct overwash path and protection by a trail berm that divides northern …

The Role Of Chemical Attractants In The Use Of Tick Traps For Life Stages Of Tick Species Ixodes Scapularis, Dermacentor Variabilis And Amblyomma Maculatum, Pamela C. Kelman

Biological Sciences Theses & Dissertations

Amblyomma maculatum, Ixodes scapularis and Dermacentor variabilis are three of the hard-bodied ticks found in the United States. This study explored three aspects of the appetence process of these tick species: attraction, desiccation survival, and locomotive activity. The first portion of this work was to improve one of the standard methods used for collecting ticks from the environment, the tick trap. To determine the attractants needed to capture all life stages of the three chosen species of ticks in the field using tick traps, a series of experiments were conducted using laboratory-reared larval, nymphal and adult A. maculatum, I. scapularis …

Predictors Patterns And Processes Of Extinction Risk In Porgies And Seabreams (Family: Sparidae), Mia Theresa B. Conteros

Biological Sciences Theses & Dissertations

A variety of human-induced changes are having profound impacts on the marine environment, and no area on the planet remains unaffected by the detrimental effects of our activities. These stressors can potentially lead to synergistic effects, causing accelerated biodiversity loss and diminished ecosystem functioning. Identification and understanding of the factors that drive species to heightened risk of extinction are important goals in conservation.

The Sparidae are commercially important and ecologically complex marine fishes; global extinction risk assessments using the IUCN Red List of Threatened Species methodology show that 9% (13 species) have increased vulnerability to population declines from intense fishing …

A Molecular Framework Phylogeny For Ptilotus (Amaranthaceae), Timothy A. Hammer

Biological Sciences Theses & Dissertations

Ptilotus (Amaranthaceae) is an Australian genus with over 100 species, most of which occur in arid Western Australia. Ptilotus has been a taxonomically difficult genus; despite rigorous morphological studies into the genus over many years, previous workers have found it difficult to delimit infrageneric groups due to inconsistent morphological variation. With the goal to establish a phylogenetic framework for the genus, 100 taxa were sampled, including 87 Ptilotus spp., and the ITS nrDNA and matK cpDNA were sequenced. The phylogeny was reconstructed using Bayesian, maximum likelihood and maximum parsimony analyses on separate and concatenated datasets. Morphological characters were assessed and …

Phylogeny And Biogeography Of The Family Haemulidae Based On A Multigene Approach, Millicent D. Sanciangco

Biological Sciences Theses & Dissertations

Haemulids are one of the most ecologically and commercially important groups of near-shore fishes. They are very diverse, with 145 putative species belonging to 18 genera. The phylogenetic relationships of the genera within the haemulids, however, are uncertain and the limits and relationships with other percomorphs are undefined.

Here, I present the first comprehensive phylogenetic hypothesis for the family based on a combined dataset of five genes (4731 bp; 16 genera, 56 species). Results show strong support for a monophyletic Haemulidae with the inclusion of the former inermiids. However, results of the analyses call into question the monophyly of a …

The Ecological Impact Of Casitas On Caribbean Spiny Lobster (Panulirus Argus) Populations In The Florida Keys, Fl, (Usa), Benjamin C. Gutzler

Biological Sciences Theses & Dissertations

Casitas are artificial structures placed on the seabed by fishermen to aggregate Caribbean spiny lobsters (Panulirus argus) for ease of capture. Some researchers suggest that they may also enhance lobster populations in shelter-limited environments. Conversely, aggregation of lobsters within casitas may be detrimental to the population if the nutritional condition or mortality of lobsters is poorer in casitas than in natural shelters. Small juvenile lobsters may be at particular risk because their foraging range is smaller and they are more readily preyed upon than larger lobsters. If so, then casitas placed in lobster nurseries may function as "ecological traps"; wherein …

Determination Of The Ecological Condition Of Benthic Communities Affected By Polycyclic Aromatic Hydrocarbons In The Elizabeth River, Chesapeake Bay, Usa, Adam M. Webb

Biological Sciences Theses & Dissertations

The Southern Branch of the Elizabeth River, a tributary of Chesapeake Bay, has historically been polluted with hydrocarbon based industrial by-products. My study compared benthic community condition from two locations in the Southern Branch: the subtidal region near Money Point, historically affected by pollution of polycyclic aromatic hydrocarbons (PAHs), to a subtidal region near Blows Creek on the opposite shore that is putatively designated as unimpacted by P AH contamination. Samples from both study sites in the Southern Branch were compared to the benthic community condition of samples from the same habitat type designations collected as part of the Chesapeake …

Benthic And Planktonic Microalgal Community Structure And Primary Productivity In Lower Chesapeake Bay, Matthew Reginald Semcheski

Biological Sciences Theses & Dissertations

Microalgal populations are trophically important to a variety of micro- and macroheterotrophs in marine and estuarine systems. In Chesapeake Bay, microalgae facilitate the survival and development of ecologically and economically relevant fauna, including shellfish and finfish populations. While regarded as significant components of coastal environments, microphytobenthic communities are historically understudied. In Chesapeake Bay, the importance of phytoplankton to the ecosystem is understood, but the contribution of microphytobenthos remains unclear. This project surveys intertidal microphytobenthic communities, in relation to phytoplankton communities, around lower Chesapeake Bay describing the taxonomic makeup of these populations, coupled with quantification of cell abundance, biomass, and primary …

Investigations Of Phytoplankton Diversity In Chesapeake Bay, Todd Arthur Egerton

Biological Sciences Theses & Dissertations

Characterizing the diversity of a community in relation to environmental conditions and ecosystem functions are core concepts in ecology. While decades of research have led to a growing comprehension of diversity in many ecosystems, our understanding in aquatic habitats and microbial organisms remains relatively limited. Phytoplankton represent a diverse and important group that contribute approximately half of global primary productivity and are intrinsically connected to changing environmental conditions, especially in systems as dynamic as estuaries. To better understand the ecological processes governing phytoplankton composition and diversity, spatial and temporal patterns of environmental parameters and their relation to the algal community …

Friends Or Foes: Interpreting The Relationship Between Two Synoptic Small Mammals In Southeastern Virginia, The Hispid Cotton Rat (Sigmodon Hispidus) And Eastern Harvest Mouse (Reithrodontomys Humulis), Sarah A. Crawford

Biological Sciences Theses & Dissertations

Relatively little is known about the relationship between the hispid cotton rat (Sigmodon hispidus) and the eastern harvest mouse (Reithrodontomys humulis). Literature on these two syntopic genera in other areas of the United States suggests that competition may exist; however, both species seem to be greatly affected by environmental changes, making it difficult to draw any definite conclusions. Live trapping and microhabitat data collected from 2 old fields in Chesapeake, Virginia over a 9-year period were used to assess the biotic and abiotic influences on space use by these two species. Each I-ha plot consisted of 2 live traps placed …

Basin Isolation And Oceanographic Features Influencing Lineage Divergence In The Humbug Damselfish (Dascyllus Aruanus) In The Coral Triangle, Jeremy M. Raynal

Biological Sciences Theses & Dissertations

The Coral Triangle (CT) is a hotspot for marine species diversity as well as for intraspecific genetic diversity. Here, nuclear RAG2 and mitochondrial D-Loop genes were used to identify deep genetic divergence among Dascyllus aruanus (Linnaeus, 1758) populations across relatively short scales within the CT. Mitochondrial clades different by greater than 20 mutational steps were geographically isolated from one another across the distance between Java and the Lesser Sunda Islands, and also east and west across the Philippines. Evidence for population structure in the Sulu Sea and at the Lesser Sunda Islands is also identified. The results suggest that the …

Carrion Beetle (Coleoptera: Silphidae) Carcass Selection: Effects Of Carcass Mass And Site Fidelity, Jonathan M. Schmude

Biological Sciences Theses & Dissertations

This study investigated reproductive behaviours of the carrion beetles (Coleoptera: Silphidae) of southeastern Virginia. Carrion beetles have been known to have ranges of carcass masses used for reproductive behaviors. In this study, pitfall traps were baited with 25g, 50g, or 75g of a cat food/mackerel mixture and left to decay and attract beetles for one week to investigate if any Silphidae species prefer a single mass over another. This study investigated the carcass bait mass that is used on the subfamily and species level, and how the beetle mass plays a role in preference. The study also investigated the effect …

Comparative Phylogeography Of The Emperor Snappers Lethrinus Lentjan And Lethrinus Harak (Lethrinidae: Percoidei) In The Coral Triangle, Andrew B. Hines

Biological Sciences Theses & Dissertations

Many questions remain regarding the origins of the well-known peak in marine biodiversity found in the Coral Triangle. Barriers to gene flow may promote lineage diversification and provide the potential for speciation contributing to the high biodiversity in this area. Population structure was examined in two species of Emperor Snappers (Lethrinidae), Lethrinus harak and Lethrinus lentjan. These species were selected because they share similar life-history traits and geographic distributions, but differ in their habitat preferences. Specimens were collected from within the Coral Triangle as well as other localities across the Indo-Pacific. To investigate phylogeographic patterns and structure a hypervariable …

Thresholds Of Change In Decomposition Rate Along A Dune/Swale Transect On A Virginia Barrier Island, Dominic J. Graziani

Biological Sciences Theses & Dissertations

Aboveground and belowground decomposition rates were determined along a barrier island dune/swale transect located on the Virginia Coast Reserve-Long Term Ecological Research Site using litterbags and wooden dowels. The objective was to determine the influence of fine scale changes in the environment on decomposition to identify any potential thresholds affecting decomposition rate. Wax myrtle (Morella cerifera L. Small) leaves and dowels of southern yellow pine wood were used as standard substrates to evaluate environmental influences on decay. Aboveground (F=6.494, p < 0.0001) and belowground (F=5.705, p < 0.0001) decay rates (yr^-1) showed significant variation among litterbag/dowel locations. Aboveground decay rates (yr^-1) ranged from 0.339 (Upper Dune station) …

Life History Of Stranded Bottlenose Dolphins (Tursiops Truncatus) In Virginia, Margaret Cook Lynott

Biological Sciences Theses & Dissertations

Little is known about the life history and overall ecology of bottlenose dolphins that strand in Virginia. In this study, I examined archived life history samples and stranding data from bottlenose dolphins found in Virginia waters to (1) develop growth curves based on ages from sectioned teeth, (2) document characteristics of male and female reproductive organs, and (3) define the relationship between age/length and presence of neonatal characteristics during the first year of life. The Gompertz growth model provided the best fit of growth data for stranded T. truncatus in Virginia. Length at birth and asymptotic length for males were …