Terrestrial and Aquatic Ecology Commons^™

Methods For Caculating The Chesapeake Bay Benthic Index Of Biotic Integrity, Roberto J. Llansó, Daniel M. Dauer

Benthic Applications

The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI evaluates the ecological condition of a sample by comparing values of key benthic community attributes (“metrics”) to reference values expected under non-degraded conditions in similar habitat types. It is therefore a measure of deviation from reference conditions.

The B-IBI is used by the Chesapeake Bay Benthic Monitoring Program, which is conducted by the Maryland Department of Natural Resources (MD DNR) and by the Virginia Department of Environmental Quality (VA DEQ). The program contains two primary elements: …

Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, I. K. Bartol, R. Mann, M. Vecchione

Biological Sciences Faculty Publications

The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors …

Fine Root Dynamics In Atlantic White Cedar (Chamaecyparis Thyoides) Wetlands: Patterns Of Ecosystem Development In Natural And Restoration Settings, Harvey Leroy Rodgers

Biological Sciences Theses & Dissertations

This work addresses seasonal and successional factors of root dynamics in natural and restoration Atlantic white cedar (AWC) wetlands. Using minirhizotrons, fine root dynamics in a chronosequence of naturally-regenerating and restoration AWC wetlands were measured to compare ecosystem development trends with restoration conditions. A second study was conducted to compare fine root dynamics in AWC wetlands with contrasting hydroperiods. In addition, a technical study was conducted to determine the feasibility of estimating root biomass with indirect minirhizotron measurements.

Root biomass estimates using minirhizotrons were significantly higher in naturally regenerating AWC wetlands and significantly lower in the restoration site relative to …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (2000), 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 second year of sampling in 2000. 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 …

Systematics Of The Subterranean Amphipod Genus Stygobromus (Crangonyctidae) In Western North America, With Emphasis On Species Of The Hubbsi Group, Daqing Wang

Biological Sciences Theses & Dissertations

This dissertation presents a study of the systematics of the subterranean amphipod genus Stygobromus of family Crangonyctidae in western North America. A total of 53 species of Stygobromus from western North America (including one species from Wisconsin) are recognized, 28 of which are new to science. All species are described and illustrated using external morphological features. A key to the western North America species of Stygobromus is given, as well as a summary of habitats of the species.

Cladistic analyses are conducted using 32 external morphological characters and two categories of outgroup choices: “all-zero” theoretical ancestor and three non-Stygobromus …

Seasonal Phytoplankton Assemblages Of Five Ephemeral Ponds In York County, Virginia, Michelle R. Kokolis

Biological Sciences Theses & Dissertations

Five ephemeral ponds were identified in and around the Grafton Ponds Natural Area Preserve, approximately 56 km north of the City of Norfolk, Virginia. These ponds, which are filled seasonally by precipitation and groundwater discharge, range from 0.1 ha to 2 ha in size and from 4 cm to 3 meters in depth. Ponds for the study were chosen based on variations in their size, depth, basin cover material, canopy openness, and historical inundation period. The purpose of this study is to relate differences in the phytoplankton assemblages to the physical and chemical characteristics of the ponds. All five ponds …

A Comparison Of Phytoplankton Communities In Lake Prince And The Western Branch Reservoir, Suffolk, Virginia, Cara Marie Muscio

Biological Sciences Theses & Dissertations

Lake Prince and the Western Branch Reservoir are two eutrophic bodies of water located in Suffolk, Virginia. Lake Prince and its two small tributaries join the Western branch via a constructed spillway. This lake system is a source of water for the surrounding municipalities, and a recreational area for community citizens. In the past, these bodies of water had repeated incidents of low oxygen and nuisance algal blooms, particularly cyanobacteria species. As a result aerators have been installed in the main body of both Lake Prince and the Western Branch Reservoir. In addition, a pipeline has been installed from North …

The Effect Of Nitrogen Fertilization On Short-Term Fine Root Dynamics In A Barrier Island Dune Community, John Walter Hutton

Biological Sciences Theses & Dissertations

Fine root dynamics are an important yet poorly understood component of terrestrial ecosystems. In recent years a number of researchers have focused on fine root dynamics; their work has looked at patterns across one or multiple growing seasons on a scale of monthly measures. The purpose of this study was to add to the overall understanding by looking at fine root dynamics on a shorter temporal scale. Minirhizotron observation tubes were used to assess the effect of nitrogen fertilization on short-term fine root dynamics in a nutrient limited, barrier island dune system. Root length elongation and mortality rates followed expected …

Biological And Physical Observations On Larval Spot (Leiostomus Xanthurus) Recruiting To Oregon And Ocracoke Inlets North Carolina, Thomas R. Wasaff

Biological Sciences Theses & Dissertations

Patterns of abundance, length, age, and growth of larval spot (Leiostomus xanthurus) were compared to assess the variability between spot larvae ingressing to two North Carolina inlets. The source of variability for the recruitment of larval fishes to estuarine nurseries has been linked to environmental stochasticity. Wind data and seasurface temperature satellite images were analyzed as two influential environmental variables that may help explain recruitment variability. As part of the South Atlantic Bight Recruitment Experiment (SABRE), spot larvae were collected between October 1994 and April 1995 as they recruited to Pamlico Sound through Oregon Inlet, located north of Cape Hatteras, …

An Analysis Of Migratory Behavior Physiological Condition And Life History Strategy In The Salamanders Ambystoma Mabeei And A. Opacum In Southeastern Virginia, Michael W. Mccoy

Biological Sciences Theses & Dissertations

Ambystoma mabeei is listed as threatened in Virginia due to its rarity and susceptibility to urbanization and poor forestry practices. The goal of this study was to identify factors that may affect the persistence of A. mabeei in Virginia by studying the life history and ecology of A. mabeei and its syntopic congener A. opacum. This information will contribute to the knowledge of life history variation within Ambystomatidae and will be critical for the development of a comprehensive management plan for A. mabeei. Population sizes of the two species and the proximate factors responsible for initiating breeding migrations were determined …

Benthic Biological Monitoring Program Of The Elizabeth River Watershed (1999), Daniel M. Dauer

Elizabeth River Reports

Executive Summary

A study of the macrobenthic communities of the Elizabeth River watershed was conducted in summer 1999. The three objectives of the Benthic Biological Monitoring Program of the Elizabeth River watershed are: (1) To characterize the health of regional areas of the tidal waters of the Elizabeth River watershed Chesapeake Bay as indicated by the structure of the benthic communities. These characterizations are based upon application of benthic restoration goals and the Benthic Index of Biotic Integrity (BIBI) developed for the Chesapeake Bay to five primary strata - the Mainstem of the river, the Lafayette River, the Southern Branch, …

A Study Of The Seasonal Composition And Abundance Of Phytoplankton And Autotrophic Picoplankton In A Brackish Water Lake In Portsmouth Virginia, Jennifer Leigh Wolny

Biological Sciences Theses & Dissertations

The phytoplankton and autotrophic picoplankton populations of Hoffler Lake, a brackish-water lake in Portsmouth, Virginia, were monitored from May 1997 through May 1998, Analyses of the phytoplankton community using the Utennohl method showed a dominance of Chlorophytes (61-88% of the total abundance) throughout the year, including a winter bloom of Chlamydomonas snowii (maximum concentration of 2.5 x 101 cells/L). Subdominants were Cyanobacteria (10-33% of the total abundance) whose composition included several species of Anabaena, Lyngbya, and a fall bloom of Microcoleus sp. Diatoms, dinoflagellates, and cryptophytes played a secondary role in the phytoplankton community of Hoffler Lake. …

The Impact Of Resident And Transient Predators On The Popultation Dynamics Of Juvenile Caribbean Spiny Lobster (Panulirus Argus) In Florida Bay, Florida, Jason Edward Schratwieser

Biological Sciences Theses & Dissertations

There has been a considerable amount of research devoted to exploring the relationship between predators and prey, but many of these studies fail to address how predation can vary over spatial and temporal scales. The tendency of ecologists to model predation as a static entity often masks its capacity for creating distinctive effects in prey populations and communities. Most predation studies also focus on the effect of a single species of predator on a prey population, an unrealistic situation in nature. In the Florida Keys, juvenile spiny lobsters are subjected to two general classes of predators: i) "resident" predators such …

Adaptive Strategies That Reduce Predation On Caribbean Spiny Lobster Postlarvae During Onshore Transport, Charles A. Acosta, Mark J. Butler Iv

Biological Sciences Faculty Publications

Like many marine species with meroplanktonic larvae, the Caribbean spiny lobster (Panulirus argus) has a postlarval stage that moves from the oceanic plankton to inshore nurseries only under specific environmental conditions (i.e., at night, in the surface water layer, on the flood tide, and during new moon), presumably to avoid predation or to enhance onshore transport. Using held and mesocosm experiments, we compared predation on planktonic postlarvae swimming at night near the surface and bottom over coastal habitats along typical offshore-inshore transport paths and determined whether predation rates differed between lunar periods (new moon vs, full moon) and with prey …

Accurate Classification Of Juvenile Weakfish Cynoscion Regalis To Estuarine Nursery Areas Based On Chemical Signatures In Otoliths, Simon R. Thorrold, Cynthia M. Jones, Peter K. Swart, Timothy E. Targett

OES Faculty Publications

We investigated the ability of trace element and isotopic signatures in otoliths to record the nursery areas of juvenile (young-of-the-year) weakfish Cynoscion regalis from the east coast of the USA. Juvenile C. regalis were captured with otter trawls at multiple sites in Doboy Sound (Georgia), Pamlico Sound (North Carolina), Chesapeake Bay (Virginia), Delaware Bay (Delaware) and Peconic Bay (New York), from July to September 1996. One sagittal otolith from each specimen was assayed for Mg/Ca, Mn/Ca, Sr/Ca and Ba/Ca ratios using inductively coupled plasma mass spectrometry (ICP-MS), while delta 13 C and delta 18 O values from the other sagittal …

Changes In Small Mammal Community Attributes Associated With Increasing Pine Stand Age In Managed Pine Plantations In Southeastern Virginia, James Douglas Dolan

Biological Sciences Theses & Dissertations

Loblolly pine plantations were examined at different ages to identify small mammal community attributes in relation to the succession of the plant community. Forest floor and understory plant communities were characterized. Small mammals were collected by Fitch (live) traps and pitfall traps in four age classes during five seasons of study. Fitch live traps and pitfall traps were used in conjunction with one another to obtain the most accurate depiction of the small mammal community. Fitch traps accounted for 65 % of small mammal captures and 7 of 9 species captured. Small mammal abundance and biomass declined with increasing stand …

Ecological Relationships Between The Marsh Rice Rat (Oryzomys Palustris) And The Meadow Vole (Microtus Pennsylvanicus) In Two Virginia Tidal Marshes, Christopher P. Bloch

Biological Sciences Theses & Dissertations

Small mammals were trapped for 23 months on two live trap grids in tidal marshes in Northampton County, on the Eastern Shore of Virginia, to examine ecological relationships between the marsh rice rat (Oryzomys palustris) and the meadow vole (Microtus pennsylvanicus). Population density, survival rates, capture probability, recruitment, residence time, and home range size were calculated for each species. Patterns of reproductive activity and fluctuations in mean weight were also observed.

There were considerable differences in population dynamics between the two sites. At Grid 2, where vegetative cover was more abundant, population densities of rice rats and meadow voles …

The Annual Reproductive Cycle Of Oryzomys Palustris In A Virginia Tidal Marsh, Erin A. Dreelin

Biological Sciences Theses & Dissertations

The objectives of my study were to determine when the marsh rice rat (Oryzomys palustris) begins and ends reproduction during the year, if there are seasonal changes in litter size, and the weight at which sexual maturity is reached. Monthly samples of rice rats were trapped from May 1995 to May 1996 in Northampton County, Virginia. Rice rats were trapped with Fitch live traps, euthanized in the field, and brought to the lab for necropsy. Data from two other studies of rice rats in Northampton County were also examined. Potential breeders did not reproduce with equal intensity throughout the …

Stomach Content Analysis Of Stranded Bottlenose Dolphins, Tursiops Truncatus, In Virginia, 1987-1996, John Mcgurk

Biological Sciences Theses & Dissertations

I examined the stomach contents from 94 bottlenose dolphins, Tursiops truncatus, that were stranded along the Virginia coastline from 1987 through 1996. Samples from 1987 through 1991 were obtained from the National Museum of Natural History (NMNH) and samples from 1992 through 1996 were collected by the Virginia Marine Science Museum (VMSM) Stranding Team. Prey species were identified using fish otoliths and cephalopod beaks.

The dolphins examined fed on 23 species of fish and one genus of cephalopods. The primary prey species was Atlantic croaker (Micropogonias undulatus); secondary species were weakfish (Cynoscion regalia), spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), …

The Diet Of Oryzomys Palustris Based On Stomach Content Analysis, Shannon L. Wright

Biological Sciences Theses & Dissertations

Oryzomys palustris (Harlan) is unusual in that it is one of two carnivorous mammals in the Family Muridae in North America. A diet analysis of Oryzomys palustris. the marsh rice rat, was done based on stomach contents. This was accomplished by taking the animals from two study areas located on the Eastern Shore of Virginia. The animals were taken monthly for one year. Once caught, the animals were sacrificed and their stomach contents were identified to the lowest taxonomic level possible. This study showed that rice rats were omnivorous mammals, eating a variety of foods, including dicots, monocots, crabs, …

Brown-Headed Cowbird (Molothrus Ater) Range Expansion Into The Southeast: Effects On The Passerine Populations Using North American Breeding Bird Survey Data, Elizabeth Pruitt Henderson

Biological Sciences Theses & Dissertations

North American Breeding Bird Survey data that were collected from 1971-1992 in Virginia, North Carolina, south Carolina, Georgia, Florida, Alabama and Tennessee were used in this analysis of the impact of Brown-headed Cowbird range expansion on four warbler and four vireo host species.

Maps of mean cowbird abundances were produced using kriging for the periods 1971-1975, 1976-1980, 1981-1985, 1986-1990 and 1991-1992. These maps illustrated a complex invasion of the southeastern United States by Brown-headed Cowbird.

Linear regression analyses of host and cowbird abundances within physiographic strata, showed no species to be in decline or increasing in abundance over the entire …

Comparison Of Sapling Community Structure In Created And Natural Forested Wetlands In Southeastern Virginia, Sharon Ann Haines

Biological Sciences Theses & Dissertations

Forested wetlands are being destroyed at a rapid rate. Wetlands are valuable for flood control, aquifer recharge, and for their role in denitrification and storage of global carbon. When wetlands are lost, their functions and value to humans are lost as well. One response to the continued development of wetlands has been the artificial creation of new wetlands. This study compared the species density, relative density, coverage and frequency of occurrence of the woody vegetation in two southeastern Virginia created wetlands with that in two reference wetlands, also in southeastern Virginia, to determine the structural similarity of their respective communities. …

The Distribution Of Rice Rats (Oryzomys Palustris) And Meadow Voles (Microtus Pennsylvanicus) In Tidal Marsh Communities On The Eastern Shore Of Virginia, Allison L. Sowell

Biological Sciences Theses & Dissertations

Two tidal marsh sites were selected for live trapping of small mammals on the Eastern Shore of Virginia. Trap grids were established at site and animals were trapped and tagged each month for one year. Habitat variables were measured at the peak of the growing season and again in late winter when vegetation was at its least luxuriant. ANOVA and multiple regressions were used to analyze the relationships between rice rats and meadow voles and associated variables related to habitat structure.

ANOVA revealed where rice rats and meadow voles differed in habitat preferences. Meadow voles were consistently captured in association …

Movement Patterns And Habitat Use Of The Copperhead Snake (Agkistrodon Contortrix) In Southeastern Virginia, Christopher Edwin Petersen

Biological Sciences Theses & Dissertations

Radiotelemetry was used to study seasonal movement patterns, habitat use, and thermal relations of nine copperhead snakes, Agkistrodon contortrix, in southeastern Virginia from May 1993 to May 1995. Daily movements ranged from 0-450 m, with 0-5 m movements accounting for 65% of the observations. The seasonal movements of males were more extensive than those of females. Differences in seasonal movements between the sexes may be due to reproductive activity of the snakes. Both males and females significantly reduced their movements prior to shedding. More time was spent using upland deciduous forests than lowland river swamps or anthropogenic habitat. Copperheads …

Zooplankton Community Dynamics In The Elizabeth River, Virginia, William C. Sharp

Biological Sciences Theses & Dissertations

Zooplankton community structure and dynamics were studied over a 12 month period in the Elizabeth River, an industrially polluted tidal river in the Chesapeake Bay estuarine system. An additional site in this estuary (Hampton Roads) was sampled for comparative purposes. Multivariate analysis indicated five distinct temporal groups occurred during the year, but there were no significant differences in spatial composition within the river. Maximum zooplankton concentrations were observed in July and lowest abundances were observed in February, March, and November. Copepods, especially Acartia species, were the most abundant components of the zooplankton community, comprising 67 to 93% of the total …

Population Dynamics Of Oryzomys Palustris And Microtus Pennsylvanicus On The Eastern Shore Of Virginia, John A. March Jr.

Biological Sciences Theses & Dissertations

The population dynamics of Oryzomys palustris, the marsh rice rat, and of Microtus pennsylvanicus, the meadow vole, were determined during a year-long mark-and-recapture study on the Eastern Shore of Virginia. Three nights of trapping per month were conducted on two live trap grids totaling 5456 total trap nights. The grids were located on Nature Conservancy land, one in Oyster, and the second at Steelman's Landing, which is east of Townsend in Northampton County Virginia. Trapped animals were evaluated using established criteria. Reproductive activity, age and sex composition, and density of the population, capture probability, survival rate, and recruitment were determined. …

Fine Root Biomass Distribution And Production Along A Barrier Island Chronosequence, Mark Jeffrey Stevenson

Biological Sciences Theses & Dissertations

Fine roots play an important role in community development on barrier islands. Fine roots can influence nutrient losses from the soil environment along with regulating water loss based on their distribution and concentration (Nobel et al., 1989; Gleeson and Tilman, 1990). A sequential coring method was used to determine fine root biomass and total biomass along a chronosequence of barrier island dunes and swales on the Virginia Coast Reserve - Long Term Ecological Research Site. Fine root production and the effects of nitrogen fertilization were also examined using an ingrowth core method along the chronosequence. Live fine root biomass, total …

The Effect Of Nitrogen Fertilization On The Phenology Of Roots In A Barrier Island Sand Dune Community, Everett P. Weber

Biological Sciences Theses & Dissertations

Little work has been done on the phenology of root growth and senescence largely due to methodological difficulties. The application of minirhizotron technology has enabled the tracking of individual roots through an entire growing season. As a result, direct measures of turnover, root growth, and an analysis of cohorts were made. Small plots on a 36 year old dune on Hog Island, a barrier island in the Virginia Coast Reserve Long Term Ecological Research Site, were fertilized with nitrogen. Minirhizotron tubes were installed in each fertilized and control plot. Each tube was sampled monthly for nine months, March through October …

Seasonal Composition Of Mesozooplankton In The Pagan River, A Nutrient Enriched Virginia Estuary, Lillian Norman Davis

Biological Sciences Theses & Dissertations

A two year study of the mesozooplankton composition and seasonal distribution was conducted in the Pagan River, a nutrient rich tidal estuary and tributary to the lower James River. The mesozooplankton was dominated by calanoid copepods (80%), with the total zooplankton abundance peaks occurring during spring and fall. The total mean abundance, 3008/m', was somewhat lower than those found by other authors, however the mean abundance at one station approximated those means. Seventy-eight percent of the calanoid copepods were Acartia spp. that were primarily responsible for the fall increase in mesozooplankton abundance. The spring increase was primarily due to increases …

Eutrophication And Macrobenthic Communities Of The Lower Chesapeake Bay: Effects Of Organic Enrichment In Pocomoke Sound, Saxis Virginia, Janice D. Mcdonnell

Biological Sciences Theses & Dissertations

The effects of organic enrichment on benthic community structure were evaluated in a field study conducted in Pocomoke Sound in the vicinity of a seafood processing plant. The empirically derived Species Abundance and Biomass (SAB) curves of Pearson and Rosenberg (1978) were used to model patterns of organic enrichment at the study site, called Pig Point, as well as two reference sites located within Pocomoke Sound. The Split Moving Windows (SMW) method was used to detect the ecotone point as defined in the Pearson and Rosenberg (1978) model and the Two Term Local Quadrat Variance (TTLQV) method was used to …