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Articles 5791 - 5820 of 6306

Full-Text Articles in Terrestrial and Aquatic Ecology

Disease Incidence Of Demersal Finfishes From The Southern And Western Branches Of The Elizabeth River, Virginia, Randal D. Owen Apr 1986

Disease Incidence Of Demersal Finfishes From The Southern And Western Branches Of The Elizabeth River, Virginia, Randal D. Owen

Biological Sciences Theses & Dissertations

Fishes from the industrialized environs of the Elizabeth River, Virginia were surveyed for external evidence of disease during June through October 1984. A highly significant (p < 0.001) incidence of disease was found in demersal fishes collected by otter trawl from a site in the industrially contaminated Southern Branch compared to a less contaminated Western Branch site. Cataracts, fin erosion and dermal lesions were the most commonly occurring anomalies in the Southern Branch finfish.

Static, solid-phase toxicity tests employing sediment collected from the Southern Branch site resulted in an immediate toxic stress in the spot, Leiostomus xanthurus, which resulted in 100% mortality within 24 hours, compared with no mortalities in control systems. Spot exposed to control, i.e., pollution free, and diluted Southern Branch sediments innoculated with the pathogenic bacterial species, Vibrio anguillarium, developed significant (p 0.020) cases of fin erosion at a mean total bacterial community density …


Organic Matter Budgets And Models For Four Plant Communities In The Great Dismal Swamp, J. Patrick Megonigal Apr 1986

Organic Matter Budgets And Models For Four Plant Communities In The Great Dismal Swamp, J. Patrick Megonigal

Biological Sciences Theses & Dissertations

Budgets and models of organic matter dynamics were developed for one mesic and three seasonally flooded plant communities in the Dismal Swamp. Components included aboveground parts, belowground parts, litter and soil organic matter (SOM).

Net primary- production was significantly greater on them flooded sites. Comparisons show that the Dismal Swamp is highly productive despite relatively low nutrient inputs.

Budget calculations showed that over 65% of the total input to SOM comes from roots. Leaves contributed about 70% of the aboveground inputs.

The model predicted that species composition, aboveground biomass and turnover rates on the cedar site will become quite similar …


Relationship Between Diameter Breast High And Diameter Near Ground Line For Hardwood Species In Arkansas, Richard A. Kluender, Jimmie L. Yeiser Jan 1986

Relationship Between Diameter Breast High And Diameter Near Ground Line For Hardwood Species In Arkansas, Richard A. Kluender, Jimmie L. Yeiser

Journal of the Arkansas Academy of Science

The relationship of diameter breast high (DBH) and diameter near ground line (DNG) was investigated for three groups of Arkansas hardwoods from four physiographic regions in the state. The relationship between DBH and DNG did not vary significantly across species groups or physiographic regions. Equations of both linear and non-linear form were developed to estimate DBH from DNG. The relationships between DBH and DNG is used to estimate timber volume, growth, and value from residual stumps. The relationship is also useful in harvesting system design and cost estimation in operational forestry.


The Case For Hunting On National Wildlife Refuges, Harvey K. Nelson Jan 1986

The Case For Hunting On National Wildlife Refuges, Harvey K. Nelson

Hunting Collection

Public land management agencies are faced with greater challenges today than ever before in responding to the recreational needs of society. As Will Rogers so aptly stated, "Land, they make so little of it nowadays" (Steinhart 1986). The U.S. Fish and Wildlife Service (FWS) also must face these challenges in management of national wildlife refuges (NWRs). There is a growing demand by the American people to utilize and enjoy NWRs in a variety of ways. Managers are faced with the dilemma of determining how much and what kind of management and utilization of natural resources is appropriate without compromising the …


The Case For Hunting, William L. Robinson Jan 1986

The Case For Hunting, William L. Robinson

Hunting Collection

My purpose at this symposium is to present the case for hunting. I am a wildlife ecologist by training and profession, and I am also a hunter. As a hunter, I am sensitive to criticisms of this pursuit, as any hunter should be. Some people question how, with knowledge of the nature and functioning of ecological systems, I can go out with a gun and kill grouse, ducks, and deer. I respond that, indeed, my understanding of ecology and the nature of man enhances my enjoyment of hunting.


Assault On Eden: Destruction Of Latin America's Rain Forests, Douglas R. Shane Jan 1986

Assault On Eden: Destruction Of Latin America's Rain Forests, Douglas R. Shane

Ecology Collection

In the seemingly distant world of Latin America's rain forests, man's greed and desperation have resulted in a fire which threatens to obscure our ability to observe life's poetry: The continuing destruction of the earth's tropical rain forests is one of the most serious environmental problems confronting humanity today: Intact, these vital organisms offer an understanding of the planet's past and a key to our future; destroyed, they threaten catastrophe of global consequence.


A Study Of Changes In Algal Population Density Diversity And Distribution And Changes In Physical And Chemical Characteristics Of Lake Elsinore, Robert H. Nyman Jan 1986

A Study Of Changes In Algal Population Density Diversity And Distribution And Changes In Physical And Chemical Characteristics Of Lake Elsinore, Robert H. Nyman

Theses Digitization Project

No abstract provided.


Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul Jan 1986

Nebraska Plant Distribution, David M. Sutherland, Robert B. Kaul

Transactions of the Nebraska Academy of Sciences and Affiliated Societies

Distribution notes based on recent collections and herbarium work are provided for 46 Nebraska plant taxa, including 43 flowering plants, two ferns, and one liverwort. The list includes several plants that are new to the State and provides range extensions within the State for many others. Several previously published distribution records believed to be erroneous are also discussed.


Woody Vegetation Of The Crystal Mountains Region, Derwood Mayo, P. L. Raines Jan 1986

Woody Vegetation Of The Crystal Mountains Region, Derwood Mayo, P. L. Raines

Journal of the Arkansas Academy of Science

Arms-length rectangle transects and nested quadrats were used to sample overstory, understory and shrub layers on south-facing mountains, north-facing mountains and flat areas along Collier and Montgomery Creeks in Montgomery County, Arkansas. Data were collected and used to calculate importance values for trees and density values for shrubs. These data indicate that the shortleaf pine-oak forest type occurs on south-facing mountains while variants of white oak-black oak-northern red oak type occur on north-facing mountains and flat areas. Beech (Fagus grandifolia Var. caroliniana [Loud.] Fern and Rehd.) is common along Collier Creek and is completely absent from Montgomery Creek watershed. The …


Survey Of The Interior Least Tern On The Arkansas And White Rivers In Arkansas, Kenneth L. Smith Jan 1986

Survey Of The Interior Least Tern On The Arkansas And White Rivers In Arkansas, Kenneth L. Smith

Journal of the Arkansas Academy of Science

No abstract provided.


The Effects Of Mute Swans On Native Waterfowl, Maria O'Brien, Robert A. Askins Jul 1985

The Effects Of Mute Swans On Native Waterfowl, Maria O'Brien, Robert A. Askins

Biology Faculty Publications

No abstract provided.


The Relationship Between Habitat Structure And Small Mammal Communities In Southeastern Virginia And Northeastern North Carolina, Roger Keith Everton Jul 1985

The Relationship Between Habitat Structure And Small Mammal Communities In Southeastern Virginia And Northeastern North Carolina, Roger Keith Everton

Biological Sciences Theses & Dissertations

A variety of terrestrial habitats was pitfall trapped in the vicinity of the Great Dismal Swamp of eastern Virginia and North Carolina to evaluate the small mammal community within the region. Habitat variables were measured at the end of the growing season on 21 0.25 ha grids. Four multivariate tests were used to examine the small mammal communities, their relationship with habitat structure, and the role of habitat selection in community structure.

Cluster and ordination analysis revealed the existence of two distinct associations of small mammals, and their habitat types, within the region. The small mammal associations were interpreted as …


The Distribution Of Ceratia Over The Mid-Atlantic Bight, Paul V. Zimba Jul 1985

The Distribution Of Ceratia Over The Mid-Atlantic Bight, Paul V. Zimba

Biological Sciences Theses & Dissertations

The distribution and concentration of Ceratium species, between Cape Hatteras, North Carolina and Long Island, New York ls discussed in relation to specific physical factors and the development of a phytoplankton bloom. The progression of high Ceratium counts Is discussed for the Bight areas of New York, Delaware, and the Chesapeake Bay (April through June). The concentration of Ceratium species declined after June, with highest concentrations along the New York and Delaware coast-lines. Coastal regions (less than 12 km from shore) were associated with high concentrations of several species. Path and regression analysis were used to relate physical factors and …


A Biochemical And Genetic Analysis Of The American Shad Alosa Sapidissima Migrating Into The Chesapeake Bay, Edward Norbert Sismour Jul 1985

A Biochemical And Genetic Analysis Of The American Shad Alosa Sapidissima Migrating Into The Chesapeake Bay, Edward Norbert Sismour

Biological Sciences Theses & Dissertations

Seven enzymes extracted from heart and liver tissues of American shad Alosa sapidissima captured during migrations into the Chesapeake Bay and Nansemond River were electrophoretically surveyed. Malate dehydrogenase and nonspecific esterase displayed polymorphic loci. The esterase polymorphism was used as a biochemical genetic marker to analyze the shad migration through the southern Chesapeake Bay. The genetic composition of the shad migration changed significantly over time indicating that this migration is probably composed of multiple, genetically divergent spawning populations. Results of this study are subject to differing interpretations. Observed temporal heterogeneity may result from separation of northern and James River stocks …


March Rice Rat, Oryzomys Palustris, Hugh H. Genoways Jan 1985

March Rice Rat, Oryzomys Palustris, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes information on other names used, description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the march rice rat, Oryzomys palustris, in Pennsylvania, USA.


Pygmy Shrew, Microsorex Hoyi, Hugh H. Genoways Jan 1985

Pygmy Shrew, Microsorex Hoyi, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes the description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the pygmy shrew (Microsorex hoyi) in Pennsylvania, USA.


Badger, Taxidea Taxus, Hugh H. Genoways Jan 1985

Badger, Taxidea Taxus, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

Includes information on another name, the description, range, habitat, life history and ecology, basis of classification, and recommendations of/for the badger, Taxidea taxus, in Pennsylvania, USA.


Notes On Three Palustrine Natural Community Types In The Arkansas Ozarks, Steve L. Orzell, William F. Pell, Gary E. Tucker Jan 1985

Notes On Three Palustrine Natural Community Types In The Arkansas Ozarks, Steve L. Orzell, William F. Pell, Gary E. Tucker

Journal of the Arkansas Academy of Science

No abstract provided.


The Green Movement: Implications For Animals, Ronnie Z. Hawkins Jan 1985

The Green Movement: Implications For Animals, Ronnie Z. Hawkins

Environment Collection

The Green movement, a newly emerging political movement that is both global in scope and firmly anchored to each local region at the grassroots level, is destined to be of great import to those concerned with the status of nonhuman animals in our society. Closely allied with deep ecology and bioregionalism, Green thinking embodies an alteration in our perception of the human organism: no longer seen as separate from and superior to all the other components of the ecosystem, our species is placed in context as one among many interdependent forms of life, with the attainment of a sustainable balance …


Introduction To Species Of Special Concern In Pennsylvania, Chapter 6--Mammals, Hugh H. Genoways Jan 1985

Introduction To Species Of Special Concern In Pennsylvania, Chapter 6--Mammals, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

First two paragraphs:

The mammals in Pennsylvania have long been under the management authority of the Pennsylvania Game Commission, but it was not until 1978 that an effort was made to deal with threatened and endangered mammals in the Commonwealth. At this time, Michael J. Puglisi was appointed as Coordinator for the Threatened and Endangered Species Program within the Game Commission. In late February 1979, Mr. Puglisi asked Hugh H. Genoways to chair an informal study group on endangered mammals in Pennsylvania. The immediate concern of this group was to be the development of a list of threatened and endangered …


Effects Of Litter On Aquatic Macrophyte Germination And Growth, Mark F. Carter, Forrest E. Lane, James B. Grace Jan 1985

Effects Of Litter On Aquatic Macrophyte Germination And Growth, Mark F. Carter, Forrest E. Lane, James B. Grace

Journal of the Arkansas Academy of Science

In Arkansas, during seasonal drought periods, lake water levels drop leaving exposed mudflats which are primary sites for seedling establishment. Commonly, these exposed mudflats are partially covered with decomposing litter from previous stands of aquatic plants. In this study, aqueous leachates from the litter of four macrophytes, Eleocharis quadrangulata, Justicia americana, Polygonum lapathifolium, and Potamogeton nodosus, were used to test for chemical interference with germination and seedling growth. Only Justicia americana leachate was found to affect the growth of several of the test species. The potential for chemical interference by Justicia litter was evaluated further using extracts of acidified leachate. …


Model To Predict Arkansas Gray Fox Fur Harvests, James H. Peck, Gary A. Heidt Jan 1985

Model To Predict Arkansas Gray Fox Fur Harvests, James H. Peck, Gary A. Heidt

Journal of the Arkansas Academy of Science

Linear regression analysis of total gray fox (Urocyon cinereoargenteus) fur harvests from 1954-1983 in Arkansas showed a high correlation with mean pelt values (r = 0.956). Single variable models using linear regression analyses of current season's pelt values (CSPV) and previous season's pelt values (PSPV) were designed to predict fur harvests. These models demonstrated high correlations for predicting harvests (r = 0.933 and r = 0.893 respectively). Regional analyses revealed a high correlation between mean pelt values and harvest for the Ozark Mountain region (r = 0.923), Ouachita Mountain region (r = 0.971 ), and Gulf Coastal Plain (r = …


Age And Growth Of The Bluegill Lepomis Macrochrius Rafinesque From An Unmanaged Watershed Lake In Northeast Arkansas With Observations On Lake Ecology, Stephen A. Sewell Jan 1985

Age And Growth Of The Bluegill Lepomis Macrochrius Rafinesque From An Unmanaged Watershed Lake In Northeast Arkansas With Observations On Lake Ecology, Stephen A. Sewell

Journal of the Arkansas Academy of Science

Age and growth data were compiled on 114 bluegill, Lepomis macrochirus Rafinesque, taken from floodwater retarding structure #15 of the Big Creek Watershed project in Craighead and Greene counties of northeast Arkansas. This project was completed in the early 1960's by USDA-SCS. The 73 surface acre lake has not been managed for fish production and has been subjected to unscheduled water level manipulations during dry weather periods. These manipulations have maintained the bluegill population in healthy condition. The oldest bluegill collected were age class IV+. Average condition coefficient K(TL)declined from oldest to youngest individuals (2.96 in age class IV+ - …


Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois Jan 1985

Gametogenesis En Chthonerpeton Indistinctum (Gymnophiona: Typhlonectidae), Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

RESUMEN:

Histológicamente, las gónadas de Chthonerpeton indistinctum son similares a las ya descritas para otras especies del orden Gymnophiona. Los lóbulos testiculares se hallan compartimentados en unidades estructurales denominadas lóculos. La espermatogénesis ocurre en cistos sincrónicos de células germinales. Durante la espermiogénesis se identifican cuatro estados consecutivos de desarrollo: 1) cistos de espermátidas redondeadas; 2) cistos de espermátidas arrifionadas; 3) cistos de espermátidas bastoniformes y 4) espermátidas en ramillete.

El análisis histológico de los ovarios mostró la presencia de tres estados en la maduración de los folículos ováricos. Estas etapas pueden ser identificadas de acuerdo a: 1) ubicación del folículo …


Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois Jan 1985

Estructura Del Ovario De Chthonerpeton Indistinctum (Reinhardt Y Lutken, 1862) (Amphibia: Gymnophiona) Durante La Gestación, Rafael O. De Sá, Nibia Berois

Biology Faculty Publications

La morfología e histología del ovario para varias especies del orden Gymnophiona ha sido reportada por Wake (1968, J. Morphol. 126, 291) y para C. indistinctum por los autores (1984, XXIV Reunión de Comunicaciones, Soc. Zool. Uruguay).

Continuando con los estudios sobre el aparato genital de esta especie vivípara, se presenta ahora la estructura del ovario durante la gestación.

Se procesaron con fines histológicos, ovarios de dos hembras grávidas colectadas en las costas de los Dep. Montevideo y San José en abril, 1983. El número de ejemplares trabajados es muy reducido dado lo difícil que resulta su colecta …


Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson Dec 1984

Benthic Diatom Community Dynamics In The Colorado River: Interactive Effects Of Periodic Dessication And Current Regime, Christopher Gerard Peterson

Publications (WR)

The response to periodic desiccation of periphyton communities developed in eddy environments or in areas exposed to variable, direct current was examined. Algal communities were incubated on clay tiles for between 2 and 12 weeks in the Colorado River, directly below Hoover Dam from October, 1983 - January, 1984. Mean daily discharge from the dam decreased over this period. To assess the influence of these discharge changes on community dynamics, samples collected over the first 12 weeks of the investigation were compared to samples of the same age collected over the final 8 weeks.

The small diatom taxon Achnahthes spp …


A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson Nov 1984

A Proposal To Fertilize The Overton Arm And Gregg Basin Areas Of Lake Mead, Larry J. Paulson

Publications (WR)

Several limnological studies have been conducted in Lake Mead during the past decade. The recent studies clearly show that most of Lake Mead is deficient in nutrients, especially phosphorus, and very low in productivity. The reservoir-wide average total phosphorus concentration for 1981 - 1982 was only 9 mg/m3. This is below levels found In most oligotrophic lakes and reservoirs. Algal biomass, as measured by chlorophyll-a, averaged only 1.5 mg/m3. That also places Lake Mead in the oligotrophic range. Transparency, as measured by a Secchi disc, averaged 9-5 m in Lake Mead during 1981-1982. That far exceeds …


Demographic Analysis And Microhabitat Relationships Of A Small Mammal Community In Clearings Of The Great Dismal Swamp, Jean Ferguson Stankavich Oct 1984

Demographic Analysis And Microhabitat Relationships Of A Small Mammal Community In Clearings Of The Great Dismal Swamp, Jean Ferguson Stankavich

Biological Sciences Theses & Dissertations

Small mammals were trapped for 14 months on two grids located within a powerline right-of-way in the Great Dismal Swamp National Wildlife Refuge. During 12,354 trap nights, individuals of 10 different species were captured. They included, from highest to lowest density, Reithrodontomys humulis, Ochrotomys nuttalli, Peromyscus leucopus, Blarina brevicauda, Synaptomys cooperi, Microtus pennsylvanicus, Microtus pinetorum, Sigmodon hispidus, Mus musculus and Oryzomys palustris. The demography (densities, reproduction, home range and dispersal) of each species was analyzed when possible. Most of the species were present in relatively low densities, with a number being captured only during the latter months of the study. …


Catalog Of The Recent Scandentia And Primates In The Carnegie Museum Of Natural History, Suzanne B. Mclaren, Duane A. Schlitter, Hugh H. Genoways Sep 1984

Catalog Of The Recent Scandentia And Primates In The Carnegie Museum Of Natural History, Suzanne B. Mclaren, Duane A. Schlitter, Hugh H. Genoways

University of Nebraska State Museum: Mammalogy Papers

The Section of Mammals, Carnegie Museum of Natural History, houses six specimens of Recent tree shrews and 611 specimens of Recent primates. The only family in the Order Scandentia is Tupaiidae. Primate families represented are Lemuridae, Lorisidae, Cebidae, Callitrichidae, Cercopithecidae, Pongidae, and Hominidae. For each specimen the following data are recorded: locality; date collected; catalog number; sex; age; nature of specimen; condition of specimen and comments. The latter category gives information on the condition of the skin and skeletal material, and gives information on the availability of the specimen.


Activity Levels Of Arboreal Rodents Peromysus And Ochrotomys Evaluated With Nest Cans In Seasonally Flooded Forests, John W. Walke Jul 1984

Activity Levels Of Arboreal Rodents Peromysus And Ochrotomys Evaluated With Nest Cans In Seasonally Flooded Forests, John W. Walke

Biological Sciences Theses & Dissertations

The diversity and density of small mammals in the Dismal Swamp are believed to be small. To test this, four 1.96 ha grids were established and operated in the Dismal Swamp National Wildlife Refuge, from September 1981 to November 1982. Number 10 metal cans covered with plastic lids were placed as nest boxes at 0.5 to 1.5 m height on trees. A 2.5 cm hole allowed access by arboreal rodents, to each nest can. The activity level of the two arboreal rodents, Peromyscus leucopus and Ochrotomys nuttalli, was evaluated by observing types of activity ranging from presence of mice to …