Ecology and Evolutionary Biology Commons^™

An Ecological Study Of The Troglobitic Cirolanid Isopod Antrolana Lira Bowman From Madisons Saltpetre Cave And Stegers Fissure, Augusta Co., Virginia, T. Lynn Collins

Biological Sciences Theses & Dissertations

An ecological study of the troglobitic cirolanid isopod, Antrolana lira Bowman, was begun in August 1979 and continued through September 1980. The isopod is restricted to two phreatic lakes in Madisons Saltpetre Cave and one phreatic lake in nearby Stegers Fissure, Augusta Co., Virginia.

All three phreatic lakes were scuba dived and surveyed. No direct connections were found between the lakes. However, physical similarities suggest that the lakes are made up of the same body of phreatic water.

Random samples were taken monthly and seasonally from the east lake in Madisons Saltpetre Cave and the lake in Stegers Fissure. Specimens …

Food Habits And Ecology Of Beavers In Southeastern Virginia, John Lennox Echternach Jr.

Biological Sciences Theses & Dissertations

The food habits and ecology of three beaver colonies in James County, Virginia were studied. Vegetation surrounding the colonies was characterized as southern mixed hardwood forest or lowland swamp forest. Stream flow values ranged from 0.013 to 0.369 m³/sec. Water depth ranged from 0.5 60 4.0 m. Caloric value of 13 heavily used woody species ranged from 3305 to 6204 cal/g. Considerable seasonal variation was noted in most species with the lowest caloric values noted in summer. No relationship was found between caloric value and frequency of use. Fresh cutting was monitored on a weekly basis and a …

A Structural Analysis Of Phytoplankton In The Chesapeake Bay Plume And Adjacent Shelf Waters, Charles K. Rutledge

Biological Sciences Theses & Dissertations

Community structures of phytoplankton populations from the southern portion of the Chesapeake Bight were examined and associated to real and environmental spaces. The sampling design was specifically intended to examine the small scale three dimensional structure of the Chesapeake Bay plume as characterized by its phytoplankton populations. The phytoplankton were sampled at 101 stations, non-synoptically, over a five day period in mid-June, 1980.

Several multivariate numerical techniques were used to determine the relationships between the phytoplankton species distributions and pattern the low salinity plume distribution. A pattern of distribution which approximated the salinity plume resulted from several clustering procedures. Environmental …

Small Mammals In Openings In Virginia's Dismal Swamp, Robert K. Rose

Biological Sciences Faculty Publications

In a study of small mammals of openings in the Dismal Swamp of Virginia, seven species were obtained using pitfall traps. Samples included several species rarely caught in the Swamp - seven specimens of the Dismal Swamp subspecies of the southern bog lemming, Synaptomys cooperi helaletes, the first collected in this century; two least shrews, Cryptotis parva; and 15 southeastern shrews, Sorex longirostris fisheri . Results are compared to previous studies, conducted primarily in forested habitats, in which the white-footed mouse, Peromyscus leucopus, and the golden mouse, Ochrotomys nuttalli, were numerically dominant.

The Effects Of Copper On Skeletonema Costatum (Greville) Cleve, Susanne Sybille Jackman

Biological Sciences Theses & Dissertations

Copper levels and dominant phytoplankton species composition were examined from six sites in Kings Creek on Virginia's Eastern Shore from March to August 1980. Creek copper levels were determined by an APDCMIBK extraction procedure and ranged from 0.003 to 0.020 mg/1. Diatoms were the dominant phytoplankters with Skeletonema costatum (Greville) Cleve emerging as a major late summer species.

Subsequent laboratory studies involved 96-hour experiments using Skeletonema costatum (clone Skel) grown in enriched natural seawater. The water was collected from Kings Creek and enriched to Guillard and Ryther's (1962) f/2 media levels. Cupric sulfate was added to the experimental culture media …

Algal Dynamics In A Cypress Stand In The Seasonally Flooded Great Dismal Swamp, Joseph A. Atchue Iii

Biological Sciences Theses & Dissertations

The dynamics of epiphytic algae and phytoplankton were studied at a cypress stand in the Great Dismal Swamp, Virginia. Mean epiphytic algal biomass was 19.9 g m^-2 and mean planktonic biomass was 3.4 g m^-2.Nutrient concentrations in the epiphytic algae and the litter were determined. The algae had mean concentrations of 1.67% and 0.18%. They were found to immobilize as much as 0.5 g N m^-2 and 0.06 g P m^-2. This suggests that the algae are important as nutrient conservers. The phytoplankton were composed primarily of Bacillariophyceae. They exhibited a more or less …

Breeding Birds Of Two Atlantic White Cedar Stands In The Great Dismal Swamp, Karen Terwilliger

Biological Sciences Theses & Dissertations

Breeding birds were censused during two years in two Atlantic white cedar stands of the Great Dismal Swamp, and a comparison was made with census results of the predominant swamp community, maple-gum. The maple-gum site had a higher bird species diversity than either cedar site but supported only half the density. The century-old cedar site had the highest species richness while the younger cedar site had the highest density.

Cluster analysis placed the avifauna into distinct groups which closely corresponded to the vegetative strata of the stands. Species were ordered along the height gradient using principal coordinate and detrended correspondence …

The Seasonality Of Occurrence Of Larval And Juvenile Sciaenids In A Virginia Seaside Estuary, James Howard Cowan Jr.

Biological Sciences Theses & Dissertations

The seasonality of occurrence and relative abundance of larval and juvenile fishes, particularly members of the family Sciaenidae, from a Virginia seaside estuary were determined from ichthyoplankton and trawl collections made from March 1979 to March 1980.

The larvae of 20 species distributed among 15 families were identified from the ichthyoplankton. Larvae of the bay anchovy, Anchoa mitchilli, and the Atlantic silverside, Menidia menidia, dominated the samples and made up 57 and 34%, respectively, of all larvae collected. Peak occurrence began in May and continued through August. Fish larvae were present in the study area all year.

Twenty-eight …

Decay Rates And Nutrient Dynamics In Confines And Nonconfined Leaf Litter In The Great Dismal Swamp, R. Frederick K. Yates

Biological Sciences Theses & Dissertations

This study was designed to quantitatively compare decay rates and nutrient dynamics by the confined and unconfined litter techniques in a seasonally flooded swamp. In this study both methods indicated the same order of decay rates among sites (cedar>maple-gum>cypress> mixed hardwood), but the unconfined method showed faster decay rates at all sites. As in two years of previous data collection, the stands exhibiting some seasonal flooding showed greater decay rates than the mixed hardwood stand which was not inundated. Nutrient dynamics were not different between litter bag and leaf pack methods.

This study included a preliminary investigation of …

The Use Of Microscopic Vegetative Characteristics And Leaf Characteristics And Leaf Deterioration Rates In The Formulation Of Keys Of Some Wetland Plants, Bruce Foy Williams

Biological Sciences Theses & Dissertations

Leaves of Spartina alterniflora, Spartina patens, Spartina cynosuroides, Distichlis spicata, Phragmites communis, Juncus roemerianus, Scirpus robustus, Typha latifolia, Iva frutescens, and Baccharis halimifolia were examined microscopically. Characteristics of each species were then used to develop identification keys. In addition, leaf fragments were buried in the marsh substrate to simulate a dredging and/or filling operation. At weekly intervals during each season of the year, a leaf fragment of each species was processed and examined to see if it could be identified.

Attributes Of Dispersing Meadow Voles In Open-Grid Populations, Raymond D. Dueser, Marcia L. Wilson, Robert K. Rose

Biological Sciences Faculty Publications

Dispersal was investigated in two open-grid populations of meadow voles, Microtus pennsylvanicus (Ord, 1815) an central Virginia (U.S.A.) from November 1974 to April 1978. "Dispersal" was defined as immigration onto open, occupied population grids. Dispersers were distinguished from residents by weight at first capture. Individuals first captured at weights <30 g were classified as residents; those first captured at >30 g were classified as dispersers. Three independent lines of evidence support the validity of the 30-g criterion for recognizing dispersers in these vole populations. With frequent trapping and high trappability, particularly of young animals, this open-grid method of study offers two advantages in the study of dispersal. First, dispersers identified …

An Evaluation Of Small Rodent Populations In Four Dismal Swamp Plant Communities, Fiona Elizabeth Breidling

Biological Sciences Theses & Dissertations

Diversity and density of small rodents in the Dismal Swamp are believed to be low. Reasons for this may be excessive predation, heavy interspecific pressure from larger rodents, lack of suitable habitat, low food availability or flooding.

Rodent populations were evaluated using live-traps and pitfall traps in four different Dismal Swamp plant communities. Habitat was compared on the basis of phytomass studies previously reported. Flood levels were recorded during live-trapping sessions. Mast from trees was collected in modified mast collectors, and fed to Peromyscus leucopus in the laboratory. Mast was analyzed for caloric value and nutrient content.

Only two …

Litter Production And Nutrient Content Of Litter In The Seasonally Flooded Dismal Swamp, Marta M. Gomez

Biological Sciences Theses & Dissertations

Litter production was studied in four plant communities in the Great Dismal Swamp, Virginia, that differ primarily in species composition and flooding regime. Greatest leaf deposition occurred in the more flooded communities, maple-gum (Acer-Nyssa) with 536 g m^-2 yr^-1 and cypress (Taxodium distichum (L.) Richard) with 528 g m^-2 yr^-1, followed by the cedar (Chamaecyparis thyoides (L.) BSP) and mixed hardwood (Quercus-Acer-Nyssa-Liquidambar) communities with 506 g m^-2 yr^-1 and 455 g m^-2 yr^-1, respectively. Litter nutrient concentrations were generally higher in the cypress and maple-gum stands, indicating greater nutrient availability …

Macrobenthic Communities Of An Industrialized Seaport Ecosystem: The Southern Branch Of The Elizabeth River, Virginia, Steven D. Hawthorne

Biological Sciences Theses & Dissertations

Macrobenthic invertebrates of an industrialized seaport ecosystem were studied seasonally from October, 1977 through July, 1978. Five stations were selected along the Southern Branch of the Elizabeth River, Virginia. The stations ranged from an area of heavy industrialization to a non-urbanized environment. At each station, bottom water was measured for salinity, temperature, dissolved oxygen, and pH. Within each sampling area, macrobenthic infauna! invertebrates were collected from in and out of channel sites along with sediment samples for various types of physicochemical analysis.

Community structure was spatially homogeneous at station sites and throughout the stations along the River. Slightly acidic pH …

The Feasibility Of Commercial Scale Culture Of Atlantic Sturgeon, Acipenser Oxyrhynchus, Christopher John Coffing

Biological Sciences Theses & Dissertations

Abstract unavailable.

Morphological Variation Among 14 Species Of Callogobius Bleeker (Pisces: Gobiidae), James Francis Mckinney

Biological Sciences Theses & Dissertations

A survey of the variation among the species of the Callogobius complex has been accomplished in order to determine if recognition of more than one genus is warranted for this assemblage of species. Emphasis has been placed on the osteological variation. Relationships among certain species within the Callogobius complex have been exposed. Although there are two well defined species groups within the complex, it is felt that inclusion of all of the examined species within the single genus Callogobius is the most parsimonious course of action.

Phytoplankton Studies Within The Virginia Barrier Islands I. Seasonal Study Of Phytoplankton In Goose Lake, Parramore Island, Harold G. Marshall

Biological Sciences Faculty Publications

The phytoplankton of Goose Lake, an oligohaline lake on Parramore Island, was studied for one year. The populations consisted primarily of ultraplankton and nanoplankton-sized forms with diatoms and chlorophyceans dominant most of the year. A general pattern of seasonally higher cell concentrations in early summer and fall was noted, with an unidentified ultraplankton-sized component prominent throughout the collection period. A list of 154 species is given.

Structure Of A Subtidal Benthic Community Near Cape Charles, Virginia, R. Michael Ewing

Biological Sciences Theses & Dissertations

Species composition, distribution, and abundance of benthic invertebrates of a subtidal community were examined at a location on the lower Delmarva Peninsula near Cape Charles, Virginia. Macrobenthos was sampled quarterly between June, 1977 and June, 1978 at nine sites along a transect in Old Plantation Creek and the adjacent offshore area. Spatial and temporal patterns of numerically important species are discussed.

Sampling sites and species were grouped by a numerical classification strategy which consisted of the Bray-Curtis similarity measure and group-average clustering. Three faunal assemblages were identified with the aid of constancy and fidelity nodal analyses: (1) a tidal creek …

Swimming As A Determinate To Immigration For Two Small Mammals In Coastal Virginia, Jeffrey Lewis Carter

Biological Sciences Theses & Dissertations

Small mammals were live trapped on the mainland and on an island located in the southeast corner of Virginia. The area was characterized by a mid-Atlantic coastal climate. White-footed mice (Perompsous fsucopus) were trapped on the mainland but not on the island, whereas meadow voles (Microtus psnnsylvimious) inhabited only the island. A series of swimming tests were performed in both the field and in the laboratory on both of these species to determine if swimming abilities could be the factor preventing Pszomysous from colonizing the island.

Both species of small mammals showed good swimming endurance in …

Seasonal Feeding Habits Of The River Otter (Lutra Canadensis) In Ditches Of The Great Dismal Swamp, Ronnie M. Pierce

Biological Sciences Theses & Dissertations

To determine the seasonal feeding habits of the river otter (Lutra canadensis) in the Great Dismal Swamp 209 scats were collected, from May 1977 to May 1978, and analyzed for content. Remains of crayfish were found with a frequency of occurrence of 82% while fish remains occurred in 62% of the scat. This is in direct contrast to previous studies (from other areas) which found fish with a greater frequency than crayfish. Fish consumption was believed to increase during periods of low water or low temperatures. Sunfish were represented most frequently and may be the preferred fish. Amphiuma remains …

The Spatial And Temporal Distribution Of Fish Eggs And Larvae In Hempstead Bay Estuary, Joseph Adelard Lessard

OES Theses and Dissertations

The ichthyoplankton of Hempstead Bay estuary was sampled from December 1972 to mid March 1974. Eleven stations were sampled by towing a 0.5 meter diameter plankton net. Eggs were most abundant during June and July with an average concentration calculated to be above 5,500/100m³. Egg densities were the lowest during the fall and winter. Larvae were most frequently taken from March through July with densities varying greatly among the samples. The eggs of Brevoortia tyrannus, Anchoa mitchilli, Tautoga onitis, Tautogolabrus adspersus, and Scophthalmus aguosus and the larvae of Menidia menidia, Ammodvtes hexapterus and Pseudopleuronectes americanus constituted most …

Additional Comments On Reproductive Strategies And Population Fluctuations In Microtine Rodents, Michael S. Gaines, William M. Schaffer, Robert K. Rose

Biological Sciences Faculty Publications

Recently, Schaffer and Tamarin (1973) proposed a model relating changes in reproductive effort (RE) to fluctuating densities in microtine rodents (lemmings and voles). They assumed (and presented data supporting this assumption) that the major effect of increased crowding would be a reduction in survival among prereproductives, thereby lowering the effective fecundity (Schaffer and Rosenzweig 1977) of their parents. As a consequence, Schaffer and Tamarin argued that the optimal reproductive expenditure, E(N), should decline with increasing population size, N. They also deduced the shape of the zero-growth isocline, N*(E), for differing levels of RE and plotted both E(N) and N*(E) on …

Animal-Sediment Relationship Study Of The Western Branch Of The Lynnhaven River, Charles Perry Seymour

Biological Sciences Theses & Dissertations

The animal-sediment relationships of the marine benthic infauna of an estuarine river system, Lynnhaven River, Virginia Beach, Virginia, were studied at six sites, sampled bimonthly for one year. Six species were found to dominate all of the sampling periods and sites for the year. The greatest number of individuals, biomass, and species were found at the sand sites. Deposit feeders were recorded in greater number than suspension feeders at both the sand and the mud sites.

Cluster and nodal analyses were successful in demonstrating animal-sediment relationships for the intertidal regions of the river system.

The Comparative Ecology Of Two Populations Of The Troglobitic Isopod Crustacean Lirceus Usdagalun (Asellidae), James Alexander Estes

Biological Sciences Theses & Dissertations

Aquatic communities of two caves in Lee Co., Virginia, were compared, and an examination was made of the life history phenomena of the troglobitic isopod Lirceus usdagalun. Measurements of physical and biological parameters were made in Thompson Cedar Cave and Gallohan Cave No. l. A contagious distribution was exhibited by populations of L. usdagalun in both caves and also by the population of another troglobitic isopod, Caecidotea recurvata, in Gallohan Cave No. 1. This distribution was attributed to aggregations of individuals which were considered to occur in areas of preference or optimal habitat patches. Lirceus usdagalun exhibited a …

The Fall And Winter Food Habits Of The Black Bear (Ursus Americanus) In The Great Dismal Swamp Of Virginia, Francis Leonard Daniel

Biological Sciences Theses & Dissertations

A study was conducted on the food habits of the black bear (Ursus americanus) in the Great Dismal Swamp of Virginia. A total of four stomachs and 42 scats were analyzed. Four samples were collected from September and October of 1975, and the remainder of the samples were collected from September 1976 to February 1977. The study was conducted to obtain information vital to the management of this species in the Great Dismal Swamp. Vitis spp. was the primary food item during the fall comprising 43% of the total diet, followed by fruits of Diospyros virginiana and Asimina triloba, each …

The Photosynthetic Action Spectra Of The Phytoplankton And Their Role In Governing Spatial And Temporal Distribution: A Numerical Modeling Approach, William Morrow Willis

OES Theses and Dissertations

In the present study a numerical modeling approach is employed to examine the role of division spedific differences in photosynthetic action spectra in governing the relative size of diatom and dinoflagellate carbon synthesis along various marine light regime gradients. A radiative transfer model taking into account both Rayleigh and Mie atmospheric optical properties is employed to define the light regime incident on the sea surface. The hydrospheric light regime is defined by an exponential decay model with a correction for diffuse back scatter. Taken together, the atmospheric and hydrospheric models define the spectral composition and intensity of light in the …

Experiments In Attempted Interspecific And Interpopulational Hybridzation Of Grass Shrimp Of The Genus Palaemonetes (Caridea Palaemonidae), Mark Andrew Boston

OES Theses and Dissertations

The present study investigates the interfertility of Palaemonetes populations, Interspecific crosses were attempted between representatives of sympatric :populations of P. pugio, P. vulgaris, and P. intermedius, Intraspecific crosses were undertaken between geographically separated :populations of P. pugio. Laboratory conditions of 25°c, 25°/oo, and 14.5 hour photoperiod per day were maintained for all breeding attempts, Under these conditions interspecific hybridization of Palaemonetes pugio and P. vulgaris was not feasible. P. intermedius could not be hybridized with P. pugio and P. vulgaris. At 40 days of age P. pugio juveniles were significantly larger than P. vulgaris juveniles of …

Herbaceous Production In Burned-Cut Burned-Uncut And Control Areas Of A Chamaecyparis Thyoides (L.) Bsp (Cupressaceae) Stand In The Great Dismal Swamp, Caroline Elisabeth Mckinley

Biological Sciences Theses & Dissertations

The herbaceous layer of an Atlantic white cedar (Chamaecyparis thyoides) stand in the Great Dismal Swamp was sampled to estimate the productivity of two burned areas and a control area. The herbaceous vegetation was sampled along three transects utilizing the harvest method and productivity values were estimated using peak biomass values for each individual species. The burned-cut area had the highest productivity (3623 kg ha^-l yr^-1) and was characterized by species of the Asteraceae, Poaceae, and Cyperaceae. The burned-uncut area had a productivity value of 1636 kg ha^-1 yr^-1 with similar species of the Asteraceae …

The Reproductive Cycle Of Microtus Ochrogaster In Eastern Kansas, Robert K. Rose, Michael S. Gaines

Biological Sciences Faculty Publications

About 800 Microtus ochrogaster were live—trapped at biweekly intervals from May 1971 through March 1973 in 3 grassland study areas in eastern Kansas, USA. Details of reproduction were determined by autopsy. Population density increased through the first winter, reached a peak in April 1972, then declined sharply during that summer and beyond. Body length, but not body mass, tended to be positively related to density. Both sexes matured at about the same weight; development was somewhat prolonged during the winter months, especially in the winter preceding the population peak. Pregnancy rates were high, approaching maximal iteroparity, throughout the study, with …

Plant Distribution And Succession Within Interdunal Depressions On A Virginia Barrier Dune System, Robert Wayne Tyndall

Biological Sciences Theses & Dissertations

A unique series of interdunal depressions was recognized on the barrier dune system of southeastern Virginia. Plant distribution and succession, and environmental factors controlling them, were studied in the series. Plant community distribution appears to be predominantly controlled by soil moisture, interspecific competition, and feral hog disturbance. Both biotic and physiographic succession are apparent with Quercus virginiana probably climax for both. Salt spray and feral hog and migratory waterfowl activity are important controlling factors of plant succession. Results indicate that the zonal appearance of shrubs and trees on the Virginia and North Carolina coasts is due to the absence of …