Ecology and Evolutionary Biology Commons^™

Landscape Ecology Of Birds On Mount Leconte, Great Smoky Mountains National Park, Andreas P. Damalas

Biological Sciences Theses & Dissertations

Landbirds form a significant component of wildlife resources in the Great Smoky Mountains National Park. The present study explored how forest structure and composition of deciduous-coniferous ecotones influenced diversity, richness, and relative abundance of bird species and how bird species responded to the spruce-fir community.

Using a form of the variable-circular plot method, I conducted audio-visual censuses of diurnal birds on Mount LeConte. I established 212 geo-referenced census points on six trails, which were used as gradient-oriented transects (gradsects). I measured habitat characteristics at the same census points. I used forest community types for each point on gradsects to delineate …

Benthic Fisheries Ecology In A Changing Environment: Unraveling Process To Achieve Prediction, Mark J. Butler Iv

Biological Sciences Faculty Publications

Marine fisheries and the ecosystems that sustain them are increasingly beset by environmental deterioration, and the problem is particularly acute in coastal zones where human Populations are increasing. In the best of circumstances, fishery managers are faced with the multiple, often conflicting, demands of resource users, politicians, and scientists when considering strategies for resource management. A further challenge is that management decisions must be made against a backdrop of a deteriorating environment and the shifting status of coastal ecosystem integrity. Traditional tools for single-species management may be inadequate in these settings. Furthermore. the necessary empirical data to appropriately parameterize models …

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus In Virginia Tidal Marshes, Christopher P. Bloch, Robert K. Rose

Biological Sciences Faculty Publications

Oryzomys palustris (marsh rice rat) and Microtus pennsylvanicus (meadow vole) cohabit coastal marshes in the mid-Atlantic US. Both were live-trapped for 23 months at two tidal marsh sites in Virginia to assess their demography near the margins of their distributions. In the presence of dense vegetation, population dynamics of the two species were seasonal and positively correlated, with densities declining through the winter. At the more sparsely vegetated site, densities of both species were lower, and densities of M. pennsylvanicus were negatively correlated with those of O. palustris. Patterns of reproduction differed between the species. O. palustris was reproductively …

Nest-Building And Spawning Behaviors In Nocomis Effusus (Actinopterygii: Cyprindae), Eugene G. Maurakis, George E. Maurakis

Virginia Journal of Science

Spawning behavior in Nocomis effusus is described from direct observations and review of videotapes made in Yellow Creek (Cumberland River drainage), Tennessee in 2003. Nest construction (i.e., excavating a concavity, forming a platform, and building a mound), and spawning behavior in N. effusus where a single breeding male excavates a pit and spawns with females on the upstream slope of his nest is like that described for Nocomis asper and Nocomis biguttatus. In digging a spawning pit, a male N. effusus reshapes and reorganizes substrate materials that results in spawning areas on the upstream slope of the nest composed …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2003), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

Macrobenthic communities of the Elizabeth River watershed have been quantitatively sampled since summer 1999. This report presents the data from the fifth year of sampling in 2003. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. ( 2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will be updated …

A Phylogeny Of Genera Of The Fish Family Nemipteridae (Percoidei) Based On The Cytochrome B Gene, Denise R. Sliter

Biological Sciences Theses & Dissertations

The species level taxonomy of the Nemipteridae is well understood but existing morphological data is insufficient to hypothesize a phylogeny of the five genera of this family of percoid fishes. Furthermore, there are three distinct and widely disparate habitat requirements within nemipterids and little is known how these evolved. Species in the genera Pentapodus, Scaevius and Scolopsis are typically found around shallow reefs. Nemipterus species are also found in shallow-water, but they inhabit strictly soft sediment bottoms. Parascolopsis is the only deep-water genus and its species are also found over soft sediments. Complete cytochrome b gene sequences (1140 base …

Strong Interactions Between Juvenile Caribbean Spiny Lobster (Panulirus Argus) And Caribbean Reef Octopus (Octopus Briareus) In The Florida Keys, Jennifer Anne Lear

Biological Sciences Theses & Dissertations

Coexisting species may simultaneously compete for resources and interact as predator and prey, creating a strong interaction that can alter the structure of animal communities. This type of interaction potentially occurs between juvenile Caribbean spiny lobster (Panulirus argus) and Caribbean reef octopus (Octopus briareus) within hard-bottom habitats in the Florida Keys, FL (USA), where octopuses may consume juvenile lobsters and also compete with them for limited crevice shelters. I conducted a series of field and mesocosm studies to investigate the nature of octopus-lobster interactions and their implications for the structure of their populations in the wild. …

Comparative Systematics Of Subterranean Amphipod Crustaceans (Hadzioidea), Thomas R. Sawicki

Biological Sciences Theses & Dissertations

The research project presented in this doctoral dissertation is a compilation of six published papers. Therefore, instead of being a single comprehensive project, it is composed of a number of sub-projects. Introductory and summary sections provide structure for the compilation of papers.

The research for this dissertation investigates the systematics of genera within the amphipod families Hadziidae Karaman, 1943 and Melitidae Bousfield, 1973. In the family Hadziidae, Bahadzia patilarga is described from an anchialine cave on the southern coast of Cuba, B. caymanensis is described from a weakly brackish-water pool in a small cave on Grand Cayman Island in the …

Seed Bank Response To Fire And Successional Trajectory Of A Virginia Small Depression Pocosin, Jay F. Bolin

Biological Sciences Theses & Dissertations

Pocosins are depressional wetlands maintained by fire. Plants in fire adapted systems can use a variety of mechanisms for survival and recruitment. I examined the seed bank response to fire (500 to 700 °C) and wet heat treatments (50 and 75 °C) in a Virginia small depression pocosin. I quantified seedling abundance, richness, and Sphagnum density. Extant vegetation was sampled with a nested plot design at each seed bank sampling area. The seed flora was compared with the extant vegetation at three size classes with Sorenson similarity values. Data from the fire treatment indicates that a simulated drought burn may …

Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval

Biological Sciences Theses & Dissertations

A quantitative understanding of habitat use of estuarine-dependent fishes is critical to the conservation of their most essential habitats. Because recruitment and fitness may be influenced by the quality of juvenile habitats, developing methods to quantify habitat-specific survivorship is pivotal to such understanding. An initial step to quantify survivorship is to validate the habitat-specific natural tags contained in otoliths. To this aim I investigated the variability in the chemistry of surface waters and otoliths of juvenile spotted seatrout, Cynoscion nebulosus, in five seagrass habitats of Chesapeake Bay, namely: Potomac, Rappahannock, York, Island, and Eastern Shore. I measured Mg, Ca, …

On The Ecological Status Of The Concept "Boundary Conditions" - A Few Methodological Remarks, Lubomira Burchardt, Krzystof Lastowski, Harold G. Marshall

Biological Sciences Faculty Publications

Plant and animal populations are frequently found in habitats where the environmental conditions are considered extreme or challenging for life form to exist. These conditions may be classified as either: (1) Supreme: a situation characteristic of degradation conditions where only a few species live under stress, and (2) Extra-ordinary: habitats that provide high biodiversity that are under stress conditions. Due to the differences in what we consider extreme conditions, it is necessary to distinguish between these two categories, because they are not comparable. Our presentation will include examples of these two extreme environmental categories.

Metabolic Rate Models And The Substitutability Of Predator Populations, David R. Chalcraft, William J. Resetarits Jr.

Biological Sciences Faculty Publications

1. Much of the debate surrounding the consequences of biodiversity loss centres around the issue of whether different species are functionally similar in their effects on ecological processes. In this study, we examined whether populations consisting of smaller, more abundant individuals are functionally similar to populations of the same species with larger, fewer individuals.
2. We manipulated the biomass and density of banded sunfish (Enneacanthus obesus) and measured their impact on populations of Southern leopard frog (Rana sphenocephala) larvae. We also evaluated the ability of models relating metabolic rate to body size to predict the relative …

Advection, Krill, And Antarctic Marine Ecosystems, Eileen E. Hofmann, Eugene J. Murphy

CCPO Publications

Advective processes are recognized as being important in structuring and maintaining marine ecosystems. In the Southern Ocean advective effects are perhaps most clearly observed because the Antarctic Circumpolar Current (ACC) provides a connection between most parts of the system, including open ocean and continental shelf regions. The ACC also provides a mechanism for large-scale transport of plankton, such as Antarctic krill (Euphousia superba Dana), which is an important component of the Southern Ocean food web. This overview provides a summary of recent observational and modelling results that consider the importance of advection to the Southern Ocean ecosystem and, in particular, …

Light Dependence Of Selenium Uptake By Phytoplankton And Implications For Predicting Selenium Incorporation Into Food Webs, Stephen B. Baines, Nicholas S. Fisher, Martina A. Doblin, Gregory A. Cutter, Lynda S. Cutter, Brian Cole

OES Faculty Publications

The potentially toxic element selenium is first concentrated from solution to a large but highly variable degree by algae and bacteria before being passed on to consumers. The large loads of abiotic and detrital suspended particles often present in rivers and estuaries may obscure spatial and temporal patterns in Se concentrations at the base of the food web. We used radiotracers to estimate uptake of both selenite (Se(IV)) and C by intact plankton communities at two sites in the Sacramento/San Joaquin River Delta. Our goals were to determine (1) whether C and Se(IV) uptake were coupled, (2) the role of …

Dinitrogen Fixation And Release Of Ammonium And Dissolved Organic Nitrogen By Trichodesmium Ims101, Margaret R. Mulholland, Deborah A. Bronk, Douglas G. Capone

OES Faculty Publications

Two methods used to measure dinitrogen (N₂) fixation (acetylene reduction and ¹⁵N₂ uptake) often result in different N₂ fixation rates. Part of the discrepancy may arise from the observation that Trichodesmium can release a fraction of their recently fixed N₂ as dissolved organic nitrogen (DON) and/or ammonium (NH4 ⁺). To resolve outstanding issues regarding N₂ fixation and the production of dissolved combined nitrogen (N) by Trichodesmium, we conducted a comprehensive analysis of N₂ fixation and the production of DON and NH₄⁺ in cultures of Trichodesmium IMS101. We performed …

Does Antarctic Krill Employ Body Shrinkage As An Overwintering Strategy?, Se-Jong Ju, H. Rodger Harvey, H. C. Shinn, Y. Kim, S. H. Kang

OES Faculty Publications

To determine if Antarctic krill employ body shrinkage as one of its overwintering mechanisms in the field, Euphausia superba and Euphausia crystallorophias were collected during fall and winter in and around Marguerite Bay through US Southern Ocean GLOBEC field programs during fall and winter 2001 and 2002. The relationships between the body length and weight of both krill species were exponentially correlated with no significant differences between the two species (p>0.05). The ratio between eye diameter and body length of individual krill was examined in an expectation that it could be used as an indicator of the body shrinkage …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: York River (1985-2002), Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded and some areas and indicators show continuing degradation. Progress in reducing nutrient inputs has made demonstrable improvements and we expect that continued progress toward nutrient reduction goals, along with appropriate fisheries management and chemical contaminant controls, will result in additional improvements to the Bay. An overall summary of findings for the major VA Bay tributaries (i.e. James, York, and Rappahannock Rivers) is bulleted below while the remainder of this …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: Rappahannock River (1985-2002), Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded and some areas and indicators show continuing degradation. Progress in reducing nutrient inputs has made demonstrable improvements and we expect that continued progress toward nutrient reduction goals, along with appropriate fisheries management and chemical contaminant controls, will result in additional improvements to the Bay. An overall summary of findings for the major VA Bay tributaries (i.e. James, York and Rappahannock Rivers) is bulleted below while the remainder of this …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: James River (1985-2002), Daniel M. Dauer, Harold G. Marshall, John R. Donat, Michael F. Lane, Suzanne C. Doughten, Frederick A. Hoffman

Status and Trends for Virginia Chesapeake Bay

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded and some areas and indicators show continuing degradation. Progress in reducing nutrient inputs has made demonstrable improvements and we expect that continued progress toward nutrient reduction goals, along with appropriate fisheries management and chemical contaminant controls, will result in additional improvements to the Bay. An overall summary of findings for the major VA Bay tributaries (i.e. James, York, and Rappahannock Rivers) is bulleted below while the remainder of this …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2002), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

A study of the macrobenthic communities of the Elizabeth River watershed was initiated in summer 1999. This report presents the data from the fourth year of sampling in 2002. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of the tidal waters of the Elizabeth River watershed as indicated by the structure of the benthic communities. ( 2) To conduct trend analyses on long-term data at 14 fixed-point stations to relate temporal trends in the benthic communities to changes in water and/or sediment quality. Trend analyses will …

Decision Process For Identification Of Estuarine Benthic Impairments, Roberto J. Llansó, Jon H. Volstad, Daniel M. Dauer

Benthic Applications

To meet the requirements of the Clean Water Act, the States of Maryland and Virginia are in the process of developing biological criteria for evaluating estuarine waters. The Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI) is the basis for these biological criteria. As an initial step, a Workgroup developed an interim framework for the application of the B-IBI to the States’ water quality inventory report (305b report) and list of impaired waters (303d list). The Workgroup included representatives of the Maryland Department of the Environment (MDE), Maryland Department of Natural Resources (MDNR), Virginia Department of Environmental Quality (DEQ), USEPA …

Feeding Responses Of Juvenile And Adult Streblospio Benedicti Webster (Spionidae) To Organic Chemicals Bound To Glass Microbeads, Heidi Kathryn Mahon

Biological Sciences Theses & Dissertations

Spionid polychaetes feed at the sediment-water interface using a pair of ciliated palps. Polychaetes select food particles based upon characteristics including size, texture, specific gravity and organic coatings. Juvenile and adult spionids have different stable isotopic carbon signals, indicating the potential to differentiate organic cues ontogenetically. In the present study, the feeding responses of juvenile and adult Streblospio benedicti Webster to seven organic coatings bound (five amino acids and two carbohydrates) to glass microbeads were tested. Juveniles and adults were highly selective for all seven types of organically coated beads. Juveniles were highly selective for threonine; whereas adults were highly …

Geographic Variation In The Morphology Of Crotalus Horridus (Serpentes: Viperidae), John Robert Allsteadt

Biological Sciences Theses & Dissertations

The Timber Rattlesnake (Crotalus horridus) occurs in discontinuous populations throughout the eastern and central United States. The species exhibits high levels of polymorphism in morphological traits, especially in coloration and pattern. Previous studies recognized either distinct northern and southern subspecies or three regional morphs (northern, southern, and western), but conflicting data sets and limited geographic sampling of previous studies have left the relationships among those regional variants unclear. In this study, univariate and multivariate statistics, together with a geographic information system, were used to analyze geographic variation in 36 morphological characters recorded from 2,420 specimens of C. horridus …

Mechanical Properties Of The Integument Of The Common Gartersnake, Thamnophis Sirtalis (Serpentes: Colubridae), Gabriel Rivera

Biological Sciences Theses & Dissertations

The evolution of the ophidian feeding mechanism has involved substantial morphological restructuring associated with the ability to ingest relatively large prey. Previous studies examining the morphological consequences of macrophagy have concentrated on modifications of the skull and cephalic musculature. Although it is evident that macrophagy requires highly compliant skin, the mechanical properties of the ophidian integument have received limited attention, particularly in the context of feeding. I examined mechanical properties of skin along the body axis in male Thamnophis sirtalis (Colubridae). From each of 11 specimens, I examined nine circumferential strips of skin, each spanning 10 ventral scales, spaced at …

Aphytophagy In The Miletinae (Lycaenidae): Phylogeny, Ecology, And Conservation, John Mathew

Biological Sciences Theses & Dissertations

Less than 1% of all Lepidoptera are aphytophagous; of these, a considerable proportion is found in the family Lycaenidae. The aphytophagous Lycaenidae are believed to have arisen from a mutualistic template involving ant attendance. With this association firmly in place, it is a relatively simple shift to exploitation, either of the ants themselves, through active carnivory on the brood/trophallactic feeding from adults, or by carnivory on ant-tended homopterans, with little to no interference by the ants. Among lycaenids, aphytophagy has arisen several times; most spectacularly in the subfamily Miletinae, where all of the approximately 150 species are presumed or known …

Male Reproductive Dynamics In The Caribbean Spiny Lobster Panulirus Argus, Jamie S. Heisig

Biological Sciences Theses & Dissertations

The population size structure of the Caribbean Spiny Lobster, Panulirus argus, in the Florida Keys, Florida (USA) has undergone a dramatic shift as a result of fishing pressure on the large individuals of the population. Male lobsters are affected most by fishing because of sexual dimorphism in size and other studies have shown that male size has direct impacts on reproductive output (i.e., number of fertilized eggs/clutch) that are independent of female size. To assess more precisely the impact of male size on fertilization success, I conducted laboratory experiments and field observations to examine various male reproductive attributes over …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: Rappahannock River (1985-2001), Daniel M. Dauer, Harold G. Marshall, Kent E. Carpenter, John R. Donat, Michael F. Lane

Status and Trends for Virginia Chesapeake Bay

This summary includes materials provided by Rick Hoffman of the Chesapeake Bay Program of the Virginia Department of Environmental Quality. Environmental information regarding other important conditions in Chesapeake Bay (e.g. submerged aquatic vegetation, fisheries, chemical contaminants) has been reported previously (Chesapeake Bay and its Tributaries: Results of Monitoring Programs And Status of Resources; 2002 Biennial Report of the Secretary of Natural Resources to The Virginia General Assembly).

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: York River (1985-2001), Daniel M. Dauer, Harold G. Marshall, Kent E. Carpenter, John R. Donat, Michael F. Lane

Status and Trends for Virginia Chesapeake Bay

This summary includes materials provided by Rick Hoffman of the Chesapeake Bay Program of the Virginia Department of Environmental Quality. Environmental information regarding other important conditions in Chesapeake Bay (e.g. submerged aquatic vegetation, fisheries, chemical contaminants) has been reported previously (Chesapeake Bay and its Tributaries: Results of Monitoring Programs And Status of Resources; 2002 Biennial Report of the Secretary of Natural Resources to The Virginia General Assembly).

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded …

Status And Trends In Water Quality And Living Resources In The Virginia Chesapeake Bay: James River (1985-2001), Daniel M. Dauer, Harold G. Marshall, Kent E. Carpenter, John R. Donat, Michael F. Lane

Status and Trends for Virginia Chesapeake Bay

This summary includes materials provided by Rick Hoffman of the Chesapeake Bay Program of the Virginia Department of Environmental Quality. Environmental information regarding other important conditions in Chesapeake Bay (e.g. submerged aquatic vegetation, fisheries, chemical contaminants) has been reported previously (Chesapeake Bay and its Tributaries: Results of Monitoring Programs And Status of Resources; 2002 Biennial Report of the Secretary of Natural Resources to The Virginia General Assembly).

The Virginia Chesapeake Bay and its tidal tributaries continue to show some environmental trends indicating progress toward restoration of a more balanced and healthy ecosystem. However, the Bay system remains degraded …

Bio-Optical Properties Of The Labrador Sea, Glenn F. Cota, W. Glen Harrison, Trevor Platt, Shubha Sathyendranath, Venetia Stuart

CCPO Publications

Three cruises were conducted during fall and spring in the Labrador Sea to investigate the effects of bio-optical properties on satellite retrievals of phytoplankton chlorophyll in this important high-latitude ecosystem. Taxon-specific and regional differences were found. Diatoms had similar to 1.5 lower chlorophyll-specific absorption but significantly higher reflectance ratios than prymnesiophytes. Particulate absorption at 443 nm for total, phytoplankton, and "detrital'' fractions was related to chlorophyll, but values were lower than reported for lower latitudes. Decreased particulate absorption is attributed primarily to pigment packaging, while low backscattering to scattering ratios result from a lower relative abundance of bacteria and picophytoplankton …