Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Ecology and Evolutionary Biology

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 811 - 840 of 951

Full-Text Articles in Entire DC Network

Temperature Regulation And The Constraints Of Climate In The Eared Grebe, Hugh I. Ellis, Joseph R. Jehl Jr Feb 2003

Temperature Regulation And The Constraints Of Climate In The Eared Grebe, Hugh I. Ellis, Joseph R. Jehl Jr

Biology: Faculty Scholarship

Eared Grebes (Podiceps nigricollis) encounter a variety of climatic regimes in their annual cycle. The most dramatic occur while on staging areas in autumn. We investigated the thermoregulatory abilities of the Eared Grebe to determine how they coped with these climate changes during staging. The basal metabolic rate (BMR) was higher than predicted. Mass-specific BMR was 1.212 mL O2/g·h for birds averaging 317 g. The thermoneutral zone is wide and extended from 15°C to 38°C. Minimal thermal conductance and average body temperature were not unusual. We conclude that Eared Grebes live most of the year under thermoneutral conditions and that …


Incorporating Local Knowledge Into Population And Habitat Viability Assessments: Landowners And Tree Kangaroos In Papua New Guinea, Philip J. Nyhus, J Williams, J Borovansky, O Byers, P Miller Jan 2003

Incorporating Local Knowledge Into Population And Habitat Viability Assessments: Landowners And Tree Kangaroos In Papua New Guinea, Philip J. Nyhus, J Williams, J Borovansky, O Byers, P Miller

Faculty Scholarship

No abstract provided.


Dangerous Animals In Captivity: Ex Situ Tiger Conflict And Implication For Private Ownership Of Exotic Animals, Philip J. Nyhus, Ronald L. Tilson, J L. Tomlinson Jan 2003

Dangerous Animals In Captivity: Ex Situ Tiger Conflict And Implication For Private Ownership Of Exotic Animals, Philip J. Nyhus, Ronald L. Tilson, J L. Tomlinson

Faculty Scholarship

The risks associated with tiger attacks on people in the wild are well documented. There may currently be more tigers in captivity than in the wild, but relatively little is known about the risks of injury or death associated with owning and managing captive tigers and other large carnivores. The purpose of this study was to conduct a global assessment of attacks by captive tigers on people, with particular emphasis on cases in the United States. Our analysis of 30 international media sources and additional documents uncovered 59 unique incidents in 1998-2001 in which people were reportedly injured or killed …


Winter 2003, Nsu Oceanographic Center Jan 2003

Winter 2003, Nsu Oceanographic Center

Currents

No abstract provided.


Human Health Effects Of A Changing Global Nitrogen Cycle, Alan R. Townsend, Robert W. Howarth, Fakhri A. Bazzaz, Mary S. Booth, Cory C. Cleveland, Sharon K. Collinge, Andrew P. Dobson, Paul R. Epstein, Elisabeth A. Holland, Dennis R. Keeney, Michael A. Mallin, Christine A. Rogers, Peter Wayne, Amir H. Wolfe Jan 2003

Human Health Effects Of A Changing Global Nitrogen Cycle, Alan R. Townsend, Robert W. Howarth, Fakhri A. Bazzaz, Mary S. Booth, Cory C. Cleveland, Sharon K. Collinge, Andrew P. Dobson, Paul R. Epstein, Elisabeth A. Holland, Dennis R. Keeney, Michael A. Mallin, Christine A. Rogers, Peter Wayne, Amir H. Wolfe

Ecosystem and Conservation Sciences Faculty Publications

Changes to the global nitrogen cycle affect human health well beyond the associated benefits of increased food production. Many intensively fertilized crops become animal feed, helping to create disparities in world food distribution and leading to unbalanced diets, even in wealthy nations. Excessive air- and water-borne nitrogen are linked to respiratory ailments, cardiac disease, and several cancers. Ecological feedbacks to excess nitrogen can inhibit crop growth, increase allergenic pollen production, and potentially affect the dynamics of several vector-borne diseases, including West Nile virus, malaria, and cholera. These and other examples suggest that our increasing production and use of fixed nitrogen …


Assessment Of Potential Environmental Impacts Of Nature-Based Tours Originating Within Clark County, Nevada, Beth Domowicz Jan 2003

Assessment Of Potential Environmental Impacts Of Nature-Based Tours Originating Within Clark County, Nevada, Beth Domowicz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this thesis was to assess the potential magnitude of negative environmental damage of nature-based tours originating in Clark County, Nevada. An ordinal ranking system was used for assessment of five variables. These variables were resource use, noise pollution, soil degradation, vegetation degradation, and wildlife disturbance. There were two proposed answers. The first was that as distance increased, negative tour impact would increase. This was not supported, since tours had high impacts for destinations that were close by and far away. The second was that most tours were not causing high damage to the environment. This hypothesis was …


Effect Of Cement Production On Vegetation In A Part Of Southwestern Nigeria, A. T. Salami, A. I. Farounbi, J. I. Muoghalu Dec 2002

Effect Of Cement Production On Vegetation In A Part Of Southwestern Nigeria, A. T. Salami, A. I. Farounbi, J. I. Muoghalu

Tanzania Journal of Science

The impact of cement dust emissions from the factory of West African Portland Cement at Ewekoro in Southwestern Nigeria on the surrounding vegetation was investigated. Sample plots of 20 m x 20 m were established at 1 km intervals from the factory site up to a distance of 10 km intervals from the factory site up to a distance of 10 km in the four cardinal directions. Leaves of common species were randomly selected for chlorophyll content analysis, leaf abundance and leaf area measurement. Woody as well as herbaceous species encountered within the established plots were enumerated, while soil samples …


Historical Changes In Mid-Water Stands Of Common Reed In The Winnebago Pool Lakes, Wisconsin, Anthony O. Gabriel, Leo R. Bodensteiner Dec 2002

Historical Changes In Mid-Water Stands Of Common Reed In The Winnebago Pool Lakes, Wisconsin, Anthony O. Gabriel, Leo R. Bodensteiner

All Faculty Scholarship for the College of the Sciences

Despite the tolerance of common reed grass to environmental extremes, mid-water stands in the Winnebago pool lakes of central Wisconsin appear to be diminishing. Formerly occupying shoreline locations, water level manipulations subsequent to dam construction beginning in the 1850's have isolated reed stands off shore. These stands have persisted but casual observations indicate that stand size has been declining. To address this perception we obtained an approximately decadal series of aerial photographs dating back to 1937 for four stands in Lake Poygan. Annual records were available for 1986–94. Using image analysis software, we determined shape and size metrics. Changes in …


Habitat Structure And Alarm Call Dialects In Gunnison's Prairie Dog (Cynomys Gunnisoni), Bianca S. Perla, C. N. Slobodchikoff Nov 2002

Habitat Structure And Alarm Call Dialects In Gunnison's Prairie Dog (Cynomys Gunnisoni), Bianca S. Perla, C. N. Slobodchikoff

Habitat Assessment and Management Collection

We examined the relationship between habitat structure and alarm call characteristics in six colonies of Gunnison’s prairie dogs (Cynomys gunnisoni) near Flagstaff, Arizona, before and after a mid-summer vegetation change. We found significant differences in alarm call characteristics between colonies, confirming the existence of alarm call dialects. Differences in frequency components but not temporal components of calls were associated with differences in habitat structure. Playback experiments revealed that differences in alarm call structure affected acoustic transmission of calls through the local habitat. Thus, we identify habitat structure as one factor that may contribute to alarm call differences between colonies of …


A Role For Natural Resource Social Science In Biodiversity Risk Assessment, Philip J. Nyhus, Frances R. Westley, Robert C. Lacey, Philip S. Miller Jan 2002

A Role For Natural Resource Social Science In Biodiversity Risk Assessment, Philip J. Nyhus, Frances R. Westley, Robert C. Lacey, Philip S. Miller

Faculty Scholarship

Biologists have made considerable progress in developing realistic simulation models to predict extinction risks for threatened species. Social scientists have to date had a more limited role in these efforts. This limited involvement comes despite the growing acknowledgment by population biologists and simulation modelers that this additional input is necessary for these models to accurately reflect the impact of humans and human-dominated landscapes on wildlife populations. We argue that collaborations among social and biological scientists can provide unparalleled opportunities to develop new conceptual and simulation tools for biodiversity risk assessment. One challenge is that while the value of interdisciplinary research …


Effects Of Management Practices On Grassland Birds: Wilson’S Phalarope, Jill A. Dechant, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss Jan 2002

Effects Of Management Practices On Grassland Birds: Wilson’S Phalarope, Jill A. Dechant, Douglas H. Johnson, Lawrence D. Igl, Christopher M. Goldade, Amy L. Zimmerman, Betty R. Euliss

United States Geological Survey: Effects of Management Practices on Grassland Birds

Information on the habitat requirements and effects of habitat management on grassland birds were summarized from information in more than 4,000 published and unpublished papers. A range map is provided to indicate the relative densities of the species in North America, based on Breeding Bird Survey (BBS) data. Although birds frequently are observed outside the breeding range indicated, the maps are intended to show areas where managers might concentrate their attention. It may be ineffectual to manage habitat at a site for a species that rarely occurs in an area. The species account begins with a brief capsule statement, which …


Unexpected Changes In Soil Phosphorus Dynamics Along Pasture Chronosequences In The Humid Tropics, Alan R. Townsend, Gregory P. Asner, Cory C. Cleveland, Margaret E. Lefer, Mercedes M. C. Bustamante Jan 2002

Unexpected Changes In Soil Phosphorus Dynamics Along Pasture Chronosequences In The Humid Tropics, Alan R. Townsend, Gregory P. Asner, Cory C. Cleveland, Margaret E. Lefer, Mercedes M. C. Bustamante

Ecosystem and Conservation Sciences Faculty Publications

Phosphorus (P) is widely believed to limit plant growth and organic matter storage in a large fraction of the world's lowland tropical rain forests. We investigated how the most common land use change in such forests, conversion to cattle pasture, affects soil P fractions along pasture chronosequences in the central Brazilian Amazon and in southwestern Costa Rica. Our sites represent a broad range in rainfall, soil type, management strategies, and total soil P (45.2–1228.0 μg P/g soil), yet we found some unexpected and at times quite similar changes in soil P in all sites. In the Brazilian sites, where rainfall …


Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman Jan 2002

Mosquito Population Dynamics During The Establishment Phase Of A Constructed Desert Wetland, April Newman

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Nature Preserve at the Clark County Wetlands Park is a constructed wetland that has the potential to produce new mosquito habitat. This thesis evaluates the potential for the development of a mosquito problem at the newly constructed wetland system by assessing the population dynamics of mosquitoes within the Nature Preserve. Based on data collected from May 2001 through January 2002, I describe fluctuations in mosquito genus and relative abundance during the first summer through winter period of wetland development.


Phosphorus Dynamics In Cultures And Natural Populations Of Trichodesmium Spp, Margaret R. Mulholland, Sheri Floge, Edward J. Carpenter, Douglas G. Capone Jan 2002

Phosphorus Dynamics In Cultures And Natural Populations Of Trichodesmium Spp, Margaret R. Mulholland, Sheri Floge, Edward J. Carpenter, Douglas G. Capone

OES Faculty Publications

Trichodesmium spp. fix atmospheric N2 and so an element other than N limits production by these species in the oligotrophic ocean. Because dissolved inorganic phosphorus (DIP) is in short supply in many marine systems, it has been hypothesized that P is a growth-limiting nutrient for these species in nature. However, Trichodesmium is capable of hydrolyzing dissolved organic P (DOP) compounds and the inorganic products from hydrolysis may provide an additional source of P for growth. We investigated P dynamics and alkaline phosphatase activity in cultures and natural populations of Trichodesmium from the Atlantic Ocean and the north coast of …


An Ethical Framework For Interpreting The United States Endangered Species Act, Cathryn M. Elgin May 2001

An Ethical Framework For Interpreting The United States Endangered Species Act, Cathryn M. Elgin

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study I argue that a holistic approach is better than an individualistic approach for interpreting the United States Endangered Species Act (ESA). I propose that the use of a holistic ethical framework, based on fundamental environmental philosophy, is better in that it more effectively fulfills the ESA's goals of species and ecosystem conservation. Holistic ethics is based on concern for a community as a whole, while individualistic ethics is based on concern for the individual. A holistic approach, I argue, is more beneficial to nature than is an individualistic approach or other non-holistic approaches. I set up basic …


Tiger Restoration In Asia: Ecological Theory Vs. Sociological Reality, Ronald Tilson, Philip J. Nyhus, Neil Franklin Jan 2001

Tiger Restoration In Asia: Ecological Theory Vs. Sociological Reality, Ronald Tilson, Philip J. Nyhus, Neil Franklin

Faculty Scholarship

No abstract provided.


The Gray Wolves (Canis Lupus) Of British Columbia’S Coastal Rainforests, Chris T. Darimont, Paul C. Paquet Jan 2001

The Gray Wolves (Canis Lupus) Of British Columbia’S Coastal Rainforests, Chris T. Darimont, Paul C. Paquet

Biogeography and Ecological Opportunity Collection

The mainland coast of British Columbia (BC) is a remote area that is comparatively free from human-caused disturbance. However, concerns about current and anticipated increases in industrial forestry activity have prompted conservation biologists to investigate the biota in this understudied region. We were commissioned by the Raincoast Conservation Society to study coastal wolves so that information could be incorporated into ongoing conservation planning and education efforts. The summer of 2000 marked the pilot season of a multi-year research project. Our team spent more than 240 person days in the field during the summer and fall seasons. We surveyed 18 mainland …


Lessons From The Motorized Migrations, David H. Ellis, George F. Gee, Kent R. Clegg, Joseph W. Duff, William A. Lishman, William J. L. Sladen Jan 2001

Lessons From The Motorized Migrations, David H. Ellis, George F. Gee, Kent R. Clegg, Joseph W. Duff, William A. Lishman, William J. L. Sladen

Proceedings of the North American Crane Workshop

Ten experiments have been conducted to determine if cranes can be led on migration and if those so trained will repeat migrations on their own. Results have been mixed as we have experienced the mishaps common to pilot studies. Nevertheless, we have learned many valuable lessons. Chief among these are that cranes can be led long distances behind motorized craft (air and ground), and those led over most or the entire route will return north come spring and south in fall to and from the general area of training. However, they will follow their own route. Groups transported south and …


Results Of The First Ultralight-Led Sandhill Crane Migration In Eastern North America, Joseph W. Duff, William A. Lishman, Dewitt A. Clark, George F. Gee, David H. Ellis Jan 2001

Results Of The First Ultralight-Led Sandhill Crane Migration In Eastern North America, Joseph W. Duff, William A. Lishman, Dewitt A. Clark, George F. Gee, David H. Ellis

Proceedings of the North American Crane Workshop

In 1997, we led 8 sandhill cranes (Grus canadensis) south from Ontario, Canada by ultralight aircraft to a wintering area near Warrenton, Virginia, an area without a wild population. Six others were transported south in a trailer in hopes they would return north with those that flew. The migration was 863 kIn long, included 14 stops, and took 21 days to complete. A1l13 SUIViving birds were wintered together. In March 1998, the surviving 7 "aircraft-led" birds departed the wintering site. The following day, 6 of the 7 were reported on the south shore of Lake Ontario. The flock …


Comparison Between Two Analytical Methods For Fecal Coliform Analysis In Natural Water: Membrane Filtration And Multiple Tube Fermentation, Mona M. Hafez Oct 2000

Comparison Between Two Analytical Methods For Fecal Coliform Analysis In Natural Water: Membrane Filtration And Multiple Tube Fermentation, Mona M. Hafez

Theses & Honors Papers

This study compares two different analytical methods for the determination of coliform bacteria within natural waters. The two methods are: 1) membrane Filtration, and 2) multiple tube fermentation. Water samples from ten different locations within the Appomattox River watershed were collected by technicians from the Piedmont Soil and Water Conservation District and the Piedmont Region TMDL Initiative in Farmville, Virginia.

The Membrane filtration (MF) method utilizes m-FC broth to isolate and differentiate total fecal coliform bacteria (E.coli, Klebsiella, Pseudomonas) in natural water samples. A 1% dilution of each water sample is filtered through a 0.45 micron (um) Millipore filter …


Responses Of Sphagnum And Carex Peatlands To Ultraviolet-B Radiation, And A Meta-Analysis Of Uv-B Effects On Vascular Plants, Peter S. Searles May 2000

Responses Of Sphagnum And Carex Peatlands To Ultraviolet-B Radiation, And A Meta-Analysis Of Uv-B Effects On Vascular Plants, Peter S. Searles

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The severity of stratospheric ozone depletion in the temperate and polar latitudes has raised concerns about the sensitivity of terrestrial vegetation and ecosystems to solar ultraviolet (UV-B) radiation. This dissertation examined the responses of plants and microbes to solar UV-B for 3 years in Tierra del Fuego, Argentina (55° S). This region is under the influence of the Antarctic "ozone hole" during the austral spring. Additionally, a quantitative review of the UV-B literature was conducted using a set of statistical techniques known as meta-analysis.

For the field studies in Tierra del Fuego, plots were established in a Sphagnum moss peatland …


How Do We Know There Is A Population-Environment Problem?, Peter J. Taylor Mar 2000

How Do We Know There Is A Population-Environment Problem?, Peter J. Taylor

Working Papers on Science in a Changing World

Five fictional friends of the author have agreed to meet and talk, hoping that he was right when he claimed that discussion crossing the usual boundaries of their fields would enrich their different inquiries and concerns. Ecolo, a natural and human ecologist, breaks the ice. He wants to marshall scientific knowledge to persuade others of the seriousness of the population problem. He is questioned by Philoso, whose philosophical bent leads her to observe the models that people use and to ask how they support the claims they make. In turn, the other three join in: Activo, an activist who is …


Final Environmental Impact Statement - Iron Point Exploraton License - Iron Point Coal Lease Tract - Elk Creek Coal Lease Tract, Volume 2, United States Department Of Agriculture -- Forest Service, United States Department Of The Interior -- Bureau Of Land Management Feb 2000

Final Environmental Impact Statement - Iron Point Exploraton License - Iron Point Coal Lease Tract - Elk Creek Coal Lease Tract, Volume 2, United States Department Of Agriculture -- Forest Service, United States Department Of The Interior -- Bureau Of Land Management

Environmental Assessments (CO)

This appendix documents BLM and Forest Service activities to involve and consult with other government agencies and the public in the preparation of the Final EIS for the potential leasing of the Iron Point and Elk Creek Coal lease tracts, as well as the issuance of a coal exploration license for an area within and surrounding the Iron Point Coal lease Tract.


Changes To The Distribution Of Posidonia Seagrass Communities Of James Point, In Response To The Development Of Cockburn Sound, Western Australia, Anthony Muscara Jan 2000

Changes To The Distribution Of Posidonia Seagrass Communities Of James Point, In Response To The Development Of Cockburn Sound, Western Australia, Anthony Muscara

Theses: Doctorates and Masters

Australia’s oceans provide many economic and environmental benefits both nationally and regionally, and are of particular social, recreational and cultural importance. Western Australia's most intensively used marine embayment is Cockburn Sound, is Cockburn Sound, it supports one of the most extensive Posidoni seagrass communities in Western Australia. The protected coastal waters off the southern metropolitan coastline of Perth arc utilised intensively for industrial, commercial and recreational purposes. Over the past 50 years, wastes have been routinely discharged into Cockburn Sound causing extensive phytoplankton and epiphyte blooms, particularly during the 1960's and 1970's. The development of industrial and naval facilities and …


Three New Hesperioidae (Hesperiinae) From South Carolina: New Subspecies Of Euphyes Bimacula, Poanes Aaroni, And Hesperia Attalus, Ronald R. Gatrelle Dec 1999

Three New Hesperioidae (Hesperiinae) From South Carolina: New Subspecies Of Euphyes Bimacula, Poanes Aaroni, And Hesperia Attalus, Ronald R. Gatrelle

The Taxonomic Report of the International Lepidoptera Survey

Euphyes bimacula arbogasti is described as a new subspecies from Berkeley County, South Carolina, United States. It is known from only a few widely scattered colonies in the coastal swamp forests of the southeastern United States from Georgia to southeastern North Carolina. It is darker then E. b. bimacula and E. b. illinois. Poanes aaroni minimus is described as a new subspecies from Bull Swamp, Orangeburg County, South Carolina. This unique inland subspecies is presently known only from the type locality. It is darker then P. a. aaroni and P. a. …


Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole Dec 1999

Reciprocal Transplantation Of The Desert Soil Crust: Can It Be Done?, Christina D. Cole

UNLV Theses, Dissertations, Professional Papers, and Capstones

A 100 meter X 100 meter study site was chosen at White Rock Springs in Red Rock Canyon National Conservation Area, Nevada. To examine Syntrichia caninervis, a desert crustal moss, reciprocal transplantations (20 mm and 40 mm diameter cores) were performed between shaded to shaded, exposed to exposed, and shaded to exposed microsites to determine if it was possible to transplant the study organism with reasonable survivorship. Transplants were inspected following rain events for percent hydration, number of dead stems, and change in percent cover. Data indicated that there was a low mortality rate of S. caninervis stems, and few …


Development Of A Novel Method For Phenol Detection Using High Performance Thin Layer Chromatography, Danette Young Carlton Aug 1999

Development Of A Novel Method For Phenol Detection Using High Performance Thin Layer Chromatography, Danette Young Carlton

Theses & Honors Papers

The purpose of this study was to develop a more efficient method to test for phenol in both wastewater and non-wastewater. Phenol is a caustic and toxic contaminant that may be present in our water supplies. Phenol is used in various resins, pharmaceuticals, plastics and disinfectants. Environmental Protection Agency methods are available to test for phenol using gas chromatography along with mass spectrometry or flame ionization detection. Each of these methods can be a long, involved process consisting of extraction, many sample injections, and interference problems. This method developed an easier and less complicated approach of testing for phenol in …


Ultraviolet-B Radiation: Effects On Pollen Of 34 Taxa, And Inheritance Patterns And Carryover Of Radiation Response In Arabidopsis, Javad Torabinejad May 1999

Ultraviolet-B Radiation: Effects On Pollen Of 34 Taxa, And Inheritance Patterns And Carryover Of Radiation Response In Arabidopsis, Javad Torabinejad

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Although considerable research has addressed effects of elevated ultraviolet-B (UV-8) radiation on vegetative plant structures and processes, the reproductive biology and patterns of inheritance of UV-B tolerance have received much less attention. I examined the effects of UV-B radiation on pollen of 34 taxa. I also addressed questions concerning the patterns of inheritance of UV-B tolerance in Arabidopsis thaliana and examined potential cumulative carryover effects of UV-B exposure through multiple generations of this species.

In the first study, a significant reduction in pollen germination occurred in only five species, but pollen tube growth in more than half of the species …


Spring 1999, Nsu Oceanographic Center Apr 1999

Spring 1999, Nsu Oceanographic Center

Currents

No abstract provided.


The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski Jan 1999

The Relative Importance Of Patch Area And Perimeter–Area Ratio To Grassland Breeding Birds, Christopher J. Helzer, Dennis E. Jelinski

School of Natural Resources: Faculty Publications

Habitat fragmentation has been implicated as a major cause of population decline in grassland birds. We tested the hypothesis that a combination of area and shape determines the use of grassland patches by breeding birds. We compared both species richness and individual species presence in 45 wet meadow grasslands in the floodplain of the central Platte River, Nebraska. Bird data were collected through the use of belt transects and supplemented by walking and listening outside transects. Our data supported our primary hypothesis that perimeter–area ratio, which reflects both the area and shape of a patch, is the strongest predictor of …