Digital Commons Network^™

Distributions Of Sharks Across A Continental Shelf In The Northern Gulf Of Mexico, J. Marcus Drymon, Sean P. Powers, John Dindo, Brian Dzwonkowski, Terry A. Henwood

University Faculty and Staff Publications

Declines in shark populations have sparked researchers and fishery managers to investigate more prudent approaches to the conservation of these fish. As managers strive to improve data collection for stock assessment, fisheries-independent surveys have expanded to include data-deficient areas such as coastal regions. To that end, a catch series from a nearshore survey off Alabama was combined with data from a concurrent offshore survey with identical methodology to examine the depth use of sharks across the continental shelf (2–366 m). The combined data set contained 22 species of sharks collected from 1995 to 2008: 21 species in the offshore data …

The Identity Of Zachaenus Roseus Cope, 1890 (Anura: Species Inquirenda), Esteban O. Lavilla, J. J. Nuñez, F. E. Rabanal, José A. Langone, Rafael O. De Sá

Biology Faculty Publications

Zachaenus roseus Cope, 1890, has puzzled systematists working in southern South America. A single individual, the holotype, has ever been collected and this specimen is in extremely poor preservation condition. Herein, the precise location of the type locality of Z. roseus is determined based on a historical review of the literature. Furthermore, following a careful comparison with all species that inhabit the southern austral forest, and that could potentially correspond to Zachaenus roseus, we conclude that this taxon is placed in the synonymy of Eupsophus calcaratus (Günther, 1881)

Conservation And Ecology Of The Yellow-Blotched Sawback (Graptemys Flavmaculata), William Winsyl Selman Ii

Dissertations

The role of species conservation is becoming increasingly important due to the mounting pressures from humans on habitats and populations of organisms. This is particularly evident in riverine ecosystems throughout the world where the human demand for freshwater resources is increasing, and consequently, the number of imperiled aquatic organisms is also growing. The seven chapters of this dissertation primarily focus on the Yellow-blotched Sawback, Graptemys flavimaculata, an endangered riverine turtle that is endemic to the Pascagoula River system of southeast Mississippi, USA. At the population level, we aimed to study the impacts of Hurricane Katrina on two study populations within …

Un Estudio Ecológico De Las Lagartijas Del Valle Seco De Buenavista Y De Los Valles Húmedos De La Josefina Y Salango, Ross Brennan

Independent Study Project (ISP) Collection

La región costera del sur de la provincia de Manabí, Ecuador es un lugar de gran biodiversidad y endemismo. En esta zona el desierto peruano del Tumbes y el bosque húmedo del Chocó se encuentran. La gran cantidad de especies endémicas y la alta biodiversidad resultan de la interacción entre las dos regiones y la diversidad de hábitats que crean. Hay bosques secos tropicales y bosques húmedos muy cerca de Puerto López. Sin embargo, esta región está cambiando rápidamente debido a las actividades humanas; hay progresiva desertificación y otras amenazas a la diversidad. Además, no hay muchos estudios de la …

Interisland Variability Of Dune Plant Community Structure On Virginia's Barrier Islands, Justin K. Shafer

Biological Sciences Theses & Dissertations

The barrier islands of the Virginia Coast Reserve LTER site provide an opportunity to study interisland variability of dune plant communities. My research focused on the variation in biomass and diversity of communities among islands and dune positions. Grassy dunes of young, intermediate and old age were sampled on Smith, Hog, and Parramore Islands. Aboveground biomass was obtained from harvest plots, and roots were extracted from cores. Data were collected on depth to groundwater and total soil nitrogen. Variation in mean aboveground biomass was evident among the islands with the highest values on Hog Island, followed by Smith, then Parramore …

Carbon Dynamics In A Phragmites Australis Invaded Riparian Wetland, Steven Walters

School of Natural Resources: Dissertations, Theses, and Student Research

Invasive plant species are widely recognized as a major threat to biodiversity and ecosystem stability. Wetland ecosystems tend to be much more susceptible to invasions because of their location on the landscape where water, nutrients, and the impacts of disturbances accumulate. Invasive plants have the ability to alter ecosystem processes and community/population dynamics. The ability of invasive plants to alter these processes can have profound economic consequences. In the United States, control of invasive wetland species alone costs approximately 155 million dollars annually. The state of Nebraska spends 2 million dollars annually controlling invasive plant species in the Platte River …

Countability Of Sandhill Cranes In Aerial Surveys, Douglas H. Johnson, John W. Solberg, Courtney L. Amundson

Proceedings of the North American Crane Workshop

Aerial surveys are used to monitor populations of many wildlife species, including sandhill cranes (Grus canadensis). In addition to the usual problems of detectability (involving both availability and perceptibility), aerial surveys of concentrated animals are subject to countability issues; from a rapidly moving aircraft, observers cannot count or accurately estimate the number of animals in a large group. Calibration is sometimes performed in an effort to adjust aerial counts for incomplete detectability and countability by calculating the ratio of animals actually in a group to the number in the group estimated from the aircraft. Here we explore alternative, …

Fall 2010, Nsu Oceanographic Center

Currents

No abstract provided.

What Is The Taxonomic Identity Of Minnesota Wolves?, L. David Mech

USGS Northern Prairie Wildlife Research Center

The taxonomic identity of the historical and current wolf (Canis lupus L., 1758 or Canis lycaon Schreber, 1775 or their hybrids) population in Minnesota (MN) and the Great Lakes region has been, and continues to be, controversial. So too does its legal status under the U.S. Endangered Species Act. This review summarizes the morphological and genetic information about that population and concludes that historically the MN population consisted of a gray wolf (C. lupus) in the west and an eastern type (Canis lupus lycaon or C. lycaon) in the east with intergrades or hybrids between …

Population Status And Geographic Distribution Of Greater Sandhill Cranes In The Mid-Continent Population, Gary L. Krapu, David A. Brandt

Proceedings of the North American Crane Workshop

Number and geographic distribution of greater sandhill cranes (Grus canadensis tabida) in the mid-continent population (MCP) of sandhill cranes were evaluated. G. c. tabida comprised 7 of 133 (5.3%) individuals of 3 subspecies which projects to 31,579 ± 11,661 (SE) individuals in an estimated spring MCP of 600,000 cranes. From a platform transmitting terminal (PTT)-marked sample representative of the geographic distribution of G. c. tabida, 10 of 13 (77%) settled during the breeding season in east-central Canada/Minnesota, including 4 in northwestern Minnesota, 4 in Manitoba (2 at sites near the Minnesota border), and 2 in Ontario. Three …

The Ratio Of Gametophytes To Tetrasporophytes Of Intertidal Chondrus Crispus (Gigartinaceae) Across A Salinity Gradient, Michele Guidone, Sean Grace

Biology Faculty Publications

Population studies of the Gigartinaceae (Rhodophyta) have often observed that the ratio of gametophytes to tetrasporophytes varies with the location of the population or the time of sampling. For some species, patterns have emerged that correlate this ratio to one or a few particular environmental variables, such as elevation, wave exposure, or season. Identifying these distributional patterns is an important step towards understanding what (if any) ecological differences exist between the two free-living life history stages.

The purpose of this study was to measure the ratio of gametophytes to tetrasporophytes of intertidal populations of Chondrus crispus across a decreasing salinity …

Behavior And Habitat Use Of Greater Sandhill Cranes Wintering In East Tennessee, David A. Aborn

Proceedings of the North American Crane Workshop

An increase of eastern greater sandhill cranes (Grus canadensis tabida) stopping over and wintering at the Hiwassee Wildlife Refuge in east Tennessee has led to overcrowding at the refuge, resulting in crane use of private property. Proper management is needed to prevent the cranes from becoming a nuisance, increase the suitability of the refuge for waterfowl, and reduce the likelihood of a disease outbreak. Observations of cranes revealed that cranes spent 83% of their time foraging, alert, or preening. Sandhill cranes foraged primarily in agricultural and grassy fields, whereas mudflats and shallow water were used for preening and …

Trophic Implications Of Light Reductions For Amphibolis Griffithii Seagrass Fauna, Adam Gartner

Theses: Doctorates and Masters

The ongoing threat of seagrass loss from reduced light availability, coupled with our lack of knowledge of associated trophic responses has motivated this characterization of the flow-on effects of light reductions to Amphibolis griffithii seagrass fauna. Recently, field manipulations of varying light reductions, induced disturbances in a A. griffithii seagrass meadow that have been shown to effect potential food resources and the structural complexity of seagrass habitats for macroinvertebrates. This offered the opportunity to assess the flow-on effects to seagrass for fauna, a topic that has seldom been examined. This study investigated the effects of different light reduction intensity (high: …