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Treefall Gaps And The Maintenance Of Species Diversity In A Tropical Forest, Stefan A. Schnitzer, Walter P. Carson

Biological Sciences Faculty Research and Publications

The maintenance of species diversity by treefall gaps is a long‐standing paradigm in forest ecology. Gaps are presumed to provide an environment in which tree species of differing competitive abilities partition heterogeneous resources. The empirical evidence to support this paradigm, however, remains scarce, and some recent studies even suggest that gaps do not maintain the diversity of shade‐tolerant species. Although there is evidence that gaps maintain the diversity of pioneer trees, most of this evidence comes from studies that did not make comparisons between gaps and intact forest sites (controls). Further, nearly all studies on the maintenance of diversity by …

2001 - The Sixth Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the Sixth Annual Symposium of Student Scholars, held on March 30, 2001. Includes abstracts from the presentations and posters.

Comparative Genetics Of Seven Plants Endemic To Florida’S Lake Wales Ridge, Eric S. Menges, Rebecca W. Dolan, Rebecca Yahr, Doria R. Gordan

Scholarship and Professional Work - LAS

Here we submit that mathematical tools used in population viability analysis can be used in conjunction with floristic and faunistic surveys to predict changes in biogeographic range. We illustrate our point by summarizing the results of a demographic study of Lobelia boykinii. In this study we used deterministic and stochastic matrix models to estimate the growth rate and to predict the time to extinction for three populations growing in the Carolina bays. The stochastic model better discriminated among the fates of the three populations. It predicted extinction for two populations in the next 25 years but no extinction of the …

Life Stage Simulation Analysis: Estimating Vital-Rate Effects On Population Growth For Conservation, M. J. Wisdom, L. Scott Mills, D. F. Doak

Wildlife Biology Faculty Publications

We developed a simulation method, known as life-stage simulation analysis (LSA) to measure potential effects of uncertainty and variation in vital rates on population growth (lambda) for purposes of species conservation planning. Under LSA, we specify plausible or hypothesized levels of uncertainty, variation, and covariation in vital rates fur a given population. We use these data under resampling simulations to establish random combinations of vital rates for a large number of matrix replicates and finally summarize results from the matrix replicates to estimate potential effects of each vital rate on lambda in a probability-based context. Estimates of potential effects are …

Ecology And Sympatric Relations Of Crevice Salamanders In Randolph County, West Virginia, Jayme Linn Waldron

Theses, Dissertations and Capstones

By implementing a mark-recapture study, I investigated the ecology of three species of sympatric plethodontid salamanders (Aneides aeneus, Desmognathus ochrophaeus, and Plethodon glutinosus) on rock outcrops in the Westvaco Wildlife and Ecosystem Research Forest, Randolph County, West Virginia. By examining activity patterns, vertical stratification, and habitat preference for A. aeneus, D. ochrophaeus, and P. glutinosus, I attempted to offer some insight into how these sympatric species avoid competition on small, isolated rock outcrops. Twenty-one surveys, both nocturnal and diurnal, were performed between 11 May and 17 October, 1999. During this time, 89 salamanders, encompassing five species ( …

Briefing Book Nebraska

United States Fish and Wildlife Service: Publications

Table of Contents

U.S. Fish and Wildlife Service Presence in Nebraska

Boyer Chute National Wildlife Refuge

Crescent Lake / North Platte National Wildlife Refuge Complex

Fort Niobrara / Valentine /John and Louise Seier National Wildlife Refuge Complex

Rainwater Basin Wetland Management District and Sandhills Habitat Office

Partners for Fish and Wildlife (PFFW)

Ecological Services (ES) Field Office

Law Enforcement

North American Waterfowl Management Plan

Nebraska Federal Aid-- Sport Fish and Wildlife Restoration

Migratory Bird Conservation

Paternity Efficiency In Turkeys Differes Extensively After Hererospermic Insemination, Ann M. Donoghue, Murray R. Bakst, Paul Drummond, Shakura Haqque, Edward J. Smith, Daniel J. Donoghue

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

All commercial turkey hens in the U.S. are bred by artificial insemination (AI).  Since semen samples are pooled from 10 or more males (heterospermic inseminations), paternity of the progeny is rarely known.  Whereas it is known that sperm competition exists, the degree to which any male's sperm fertilizes ova relative to other male's remains unknown.  In this work, we determined individual male fecundity relative to that of other males in the study and attempted to establish a relationship between male fecundity and semen characteristics in turkeys.  Fingerprinting of genomic DNA from parents and offspring was used to determine parentage efficiency. …

Cattle Production In The Gascoyne And Interior Regions Of Western Australia; A Report On The Cunyu Demographic Study (1990-1998) And The Mt Clere Producer Demonstration Site (1993-1997), Andrew Thomson

Agriculture reports

Although Producer Demonstration Sites have been staged widely in the northern parts of Australia, the events at Cunyu and Mt Clere herald a first for such an in-depth investigation in the mulga shrub lands of Western Australia.

Insect Herbivory Above- And Belowground: Individual And Joint Effects On Plant Fitness, John L. Maron

Biological Sciences Faculty Publications

Understanding of the selective effects of insect herbivory on plants comes primarily from studies of herbivory aboveground. The impact of belowground herbivory, either in isolation or in concert with herbivory aboveground, on plant fitness is only beginning to be understood.

I reduced the densities of root-boring ghost moth (Hepialus californicus) larvae and/or flower- and seed-feeding insects of bush lupine (Lupinus arboreus), a woody shrub, and followed fecundity and survival of plants for three years. In year one, suppression of aboveground herbivores increased mean seed output by 31%, but suppression of belowground herbivores had no significant effect …

Factors Concerning The Conservation Of A Rare Shale Endemic Plant: The Reproductive Ecology And Edaphic Characteristics Of Penstemon Debilis (Scrophulariaceae), Amy L. Mcmullen

Biology

The management of a rare, edaphic endemic plant species requires an understanding of the ecological setting and processes that contribute to its restriction. Included in the ecological processes is a set of biotic characters associated with the reproductive ecology, including its breeding system, pollination vectors, and germination requirements. The geologic and soil setting of the plant must also be characterized in order to understand the plant's restriction to the substrate. These issues were addressed by this study of the rare endemic Penstemon debilis O'Kane and Anderson (Scrophulariaceae). Penstemon debilis consists of six populations that occur on talus slopes of the …

Demographic Viability Of Populations Of Silene Regis In Midwestern Prairies: Relationships With Fire Management, Genetic Variation, Geographic Location, Population Size And Isolation, Eric S. Menges, Rebecca W. Dolan

Scholarship and Professional Work - LAS

1. We studied the demographic viability of populations of a long-lived iteroparous prairie perennial, Silene regia, in relation to management regimes, population sizes, geographical region (Ohio and Indiana vs. Missouri and Arkansas), degree of isolation and amount of genetic variation. Demographic data were collected from 16 populations for up to 7 years.

2. This species has high survivorship, slow growth, frequent flowering and episodic seedling recruitment. Matrix projection methods were used to summarize population performance with and without recruitment. Median finite rates of increase by population varied from 0.57 to 1.82 and from 0.44 to 0.99, respectively.

3. Populations with the highest rates …

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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 …

Secondary Reproductive Strategies Of The Eastern Kingbird (Tyrannus Tyrannus), Assessed By Dna Fingerprinting And Egg Physiognomy, Diane L. Rowe

Biology

Extra-pair fertilization, a secondary breeding strategy, was detected in the eastern kingbird (Tyrannus tyrannus) using multi-locus DNA fingerprinting. I assessed the genetic parentage of 20 broods in a population of kingbirds in central New York. Two DNA probes were used to test for exclusion of nestlings as true offspring of one or both social parents. Band-sharing coefficients and the number of novel bands were used to discern which parent was not a first-degree relative of the nestling in question. No cases of conspecific brood parasitism or quasi-parasitism were documented. However, extra-pair paternity was found to be very common, …

A Quantitative Study Of Diet In Three Species Of Rodents In Natural And Irrigated Savanna Fields, Safianu Rabiu, Robert K. Rose

Biological Sciences Faculty Publications

During July, 1990 - June, 1992 we collected stomach contents of necropsied rodents that totalled 494 Arvicanthis niloticus (Desmarest, 1822), 356 Mastomys natalensis (Smith, 1834) and 273 Tatera valida (Wroughton, 1906) from natural, savanna fields in Nigeria, and 528 Arvicanthis and 367 Mastomys from nearby irrigated fields, where Tatera was never trapped. The materials were processed and microscopically analyzed to determine patterns of diet selection. Sites were sampled for vegetative cover and rodent food resources. More than 90% of the stomach materials could be identified to one of four categories: dicots (vegetative), monocots (vegetative), seeds, and insects. Seeds constituted approximately …

Growth And Survival Of Colorado Squawfish In The Upper Colorado River, D. B. Osmundson, Ronald J. Ryel, T. E. Mourning

Wildland Resources Faculty Publications

Growth and adult survival rates were estimated for the endangered Colorado squawfish Ptychocheilus lucius inhabiting the upper Colorado River by using data from fish captured during 1990–1995. Mean annual growth rates of fish aged 3–6 years ranged from 32.2 (age 6) to 82.0 (age 3) mm/year. Growth rates for older fish were highest for fish 400–449 mm total length, TL, (42.7 mm/year) and declined to 19.8 mm/year for fish 500–549 mm TL. Fish 550 mm and longer grew an average 9.5 mm/year. Survival rates for fish 550 mm and longer were estimated by comparing measured size distributions with simulated stable …

Understanding Of Wetlands As Expressed By Selected Community Leaders, Donald Nathan Bardole

Dissertations and Theses @ UNI

This study focuses on ascertaining the understanding of wetlands by selected community and state leaders and determining the source of that knowledge. Because of the subjects' positions of influence, this information may become an important element in understanding the decisions made by those community and state leaders. An interview survey was designed and piloted for this study. Community and state leadership positions were first delineated and then individuals selected from each category. The subjects varied considerably in their knowledge of wetlands, showed the presence of professional expediency, and agreed that regulation in some form is necessary. The wetlands knowledge held …

The Natural History Of Aconitum Noveboracense Gray (Northern Monkshood), A Federally Threatened Species, Margaret A. Kuchenreuther

Journal of the Iowa Academy of Science: JIAS

Aconitum noveboracense Gray (Ranunculaceae), commonly known as northern monkshood, is a federally threatened herbaceous perennial that occurs in disjunct populations in Iowa, Wisconsin, Ohio and New York. It appears to be a glacial relict, existing today only in unique areas with cool, moist microenvironments, such as algific talus slopes. Field studies reveal that A. noveboracense has a complex life history. Perennation of individual plants occurs through the annual production of daughter tubers. Vegetative reproduction is commonly observed, and can occur by means of aerial and subterranean bulbils, as well as by development of adventitious root buds. Populations also reproduce sexually …

Ecology And Community Relationships Of The River Cooter, Pseudemys Concinna In A Southern Illinois Backwater, Michael J. Dreslik

Masters Theses

In Illinois the River cooter, Pseudemys concinna, is an enigmatic endangered species. Even throughout its range, ecological studies on the River cooter are rare. During 1994 and 1995 I quantified the: growth rates and trends, population size and structure and dietary habits of a population from floodplain lake in Gallatin county, Illinois. Population estimation (Schnabel method) predicted 136 individuals at a density of 4.6 turtles/ha with a biomass of 3.6 Kg/ha. The sex ratio is slightly male biased (1:1.14). From back-calculated growth data, the von Bertalanffy growth model (Fabens' method) estimates males with a higher growth rate (k) and …

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. …

Effects Of Reproductive Mode On Demography And Life History In Arabis Fecunda (Brassicaceae), Peter Lesica, J. Stephen Shelly

Biological Sciences Faculty Publications

Life history theory predicts that trade-offs between growth and reproduction should be dictated by a population's mortality schedule. We tested this prediction with Arabis fecunda, a short-lived perennial that occurs in many different habitats in southwest Montana. Individuals produce either or both axillary or terminal inflorescences. Axillary-flowering plants are usually iteroparous and have smaller reproductive bouts, while terminal-flowering plants have larger reproductive bouts, and tend to be semelparous. We recorded size and fecundity of A. fecunda individuals from 1989 to 1993 in three different habitats. There was great variation in demographic and life history traits among the populations. A …

Population Dynamics In Response To Fire In Quercus Laevis - Pinus Palustris Barrens And Related Communities In Southeast Virginia, Allen E. Plocher

Biological Sciences Theses & Dissertations

Permanent plots in the Zuni Pine Barrens (Isle of Wight Co., Virginia) were sampled in order to: quantify plant population dynamics in response to fire, compare these dynamics among different moisture regimes, compare the effect of mechanical understory removal to that of fire on tree seedling and herbaceous dynamics, and determine the effect of dense lichen (Cladonia spp.) coverage on pine seedling establishment and survival. Fire resulted in 40% aboveground mortality in the overstory, 80% in the sapling/large shrub layer, and nearly 100% in the understory, followed by a 3.3 to 10.6 fold increase in understory density. Regeneration …

A Survey Of The Stony Coral Community Composition Of Pompano Ledge, Broward County, Florida, With A Preliminary Evaluation Of The Effectiveness Of Mooring Buoys In Reducing Coral Damage, John D. Hocevar

HCNSO Student Theses and Dissertations

Stony corals of Pompano Ledge, First Reef, Broward County, Florida were sampled in situ using a new reef assessment method. The circular-radial method was used to assess the effectiveness of mooring buoys in reducing damage to reefs. Data will be part of a long-term monitoring study of·buoy impacts. The parameter of recent injury was used to provide preliminary information on buoy effectiveness.

Results were as follows: approximately 6% of the study area was covered by stony corals, with an average of 3 colonies per square meter. Diversity based on abundance (H'n) was 1 .7, and diversity based on relative coverage …

Handbook Of Field Methods For Monitoring Landbirds, C. John Ralph, Geoffrey R. Geupel, Peter Pyle, Thomas E. Martin, David F. Desante

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

This handbook is a compilation of methods that can be used to assay population size, demographics, and status of many species of birds occurring in a wide variety of habitats. The handbook will prove useful to field biologists, managers, and scientists anywhere in the New World from the arctic through the tropics. The methods include four types of censuses for determining population size and trends, mist-netting and nest searches to determine demographic parameters, and other methods that will be useful in operating a monitoring station, including habitat and weather observations, and suggestions for training personnel and possibilities for detailed studies. …

Importance Of Mild Hyperoxaluria In The Pathogenesis Of Urolithiasis - New Evidence From Studies In The Arabian Peninsula, W. G. Robertson, H. Hughes

Scanning Microscopy

The hypothesis that mild hyperoxaluria is more important than hypercalciuria in the pathogenesis of urolithiasis is re-examined in the light of new evidence. Small increments in urinary oxalate in the normal to high-normal range are much more critical than similar rises in urinary calcium for increasing the relative supersaturation of urine with respect to calcium oxalate, the oxalate/calcium ratio in urine, the total volume of calcium oxalate crystals excreted, the proportion of abnormally large crystals and aggregates of calcium oxalate and the severity of the disorder as defined by the recurrence rate of stone-formation. Data from the Arabian Peninsula, where …

Interactions Between Populations Of Intermediate Wheatgrass And Western Wheatgrass As Influenced By Short-Duration Grazing And Moisture Availability, Gerrit B. Bartels

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of grazing and moisture availability on the competitive interactions of intermediate wheatgrass (Thinopyrum intermedium (Host) Barkw. & D.R. Dewey) and western wheatgrass (Pascopyrum smithii (Rhydb.) A. Love) were examined under a short-duration grazing system in central Utah. The fate of tiller cohorts was observed at approximately monthly intervals at the interface between patches of these two rhizomatous grasses and in monospecific stands. The effects of short-duration grazing, clipping of western wheatgrass following grazing to achieve levels of utilization equivalent to that of intermediate wheatgrass, irrigation, and removal of the competitor were assessed in terms of the …

Population Ecology Of Polydora Ligni (Polychaeta: Spionidae). Ii. Seasonal Demographic Variation And Its Potential Impact On Life History Evolution, Roman Zajac

Biology and Environmental Science Faculty Publications

Seasonal demographic variation was studied in an estuarine population of the opportunistic polychaete Polydora ligni between May 1982 and November 1983 in Alewife Cove, Connecticut, USA. The demography of 15 cohorts settling during this period was analyzed using life cycle graph models. Cohorts settling in spring and early summer had the shortest life spans (≈ 10 wk); highest survivorship over all life cycle stages and adult females produced an estimated maximum of 6 larval broods. Early adult stages contributed most to population growth during this period, and the potential for population growth, λ, was the highest during the study. Late …

Survivorship And Recruitment In A Long-Lived Prairie Perennial, Ipomoea Leptophylla (Convolvulaceae), Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Little is known of the lifespans of herbaceous plants, especially in grasslands, although this information is basic to understanding the dynamics of species and ecosystems. Permanently marked plants of the bush morning glory, Ipomoea leptophylla (Convolvulaceae), in Nebraska sandhills prairie were censused annually from 1979-1989. While the average annual death rate was 2.6 per 100, virtually all the mortality was among smaller and probably younger plants. Recruitment varied greatly among years. Of plants of known age, the median age at first flowering was 6 yr. After 9 yr 30% had never flowered. Larger size classes flowered more frequently than smaller …

Upholstered Potential In The U.S. And Canada, Gary M. Kellum, Eric J. Todd, Steven H. Bullard

Faculty Publications

The potential market for upholstered furniture sales in the near future appears to be quite favorable in both the United States and Canada. A recent survey indicates that 48 percent of U.S. house· holds,and 54 percent of Canadian households are planning to purchase some type of upholstered furniture in the next 4 to 5 years.

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …

Dna Fingerprinting Analysis Of Captive Asian Elephants, Elephas Maximas, Laura Louise Bischof

Dissertations and Theses

This thesis examined the effectiveness of DNA fingerprinting analysis for paternity ascertainment and the establishment of relatedness of captive Asian elephants (Elephas maximas). Eighteen Asian elephants from three North American zoos were examined. Thirteen of these elephants were wild caught. Relationships between these elephants and the remaining elephants born in captivity were known.