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Articles 121 - 150 of 162

Full-Text Articles in Life Sciences

Season And Distance From Forest - Old Field Edge Affect Seed Predation By White-Footed Mice, Scott J. Meiners, James T. Mccormick Jan 2000

Season And Distance From Forest - Old Field Edge Affect Seed Predation By White-Footed Mice, Scott J. Meiners, James T. Mccormick

Scott J. Meiners

We studied the spatial pattern of seed predation across a forest-old field edge in both fall and winter to assess the potential for seed predators to influence plant spatial patterns. We used a 100 x 100 m grid that began 30 m inside the forest and extended 60 m into the old field. Inside this grid we placed seed stations at regular 10 m intervals and monitored seed removal. Seed predation varied significantly across the edge gradient in both fall and winter with the highest rate of seed removal at the edge in both trials. The spatial pattern of seed …


Sagina (Caryophyllaceae) In Illinois: An Update, Gordon C. Tucker Jan 2000

Sagina (Caryophyllaceae) In Illinois: An Update, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason Jan 2000

Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason

Paul V. Switzer

The implications of insects’ vision for territorial defense have been relatively little studied in the field. In the dragonfly Perithemis tenera Say we investigated whether either the angle at which an intruder was viewed by a territorial resident or the background against which it was viewed affected the detection of that intruder. Residents detected intruders at a greater distance if the intruders were directly in front of them; they also detected more intruders in front of them than from other angles. Intruders viewed against distant vegetation were detected more readily than were intruders against near vegetation. Residents detected more intruders …


School Foodservice Director’S Perceived Compliance With The Dietary Guidelines For Americans, Melanie Burns Jan 2000

School Foodservice Director’S Perceived Compliance With The Dietary Guidelines For Americans, Melanie Burns

Melanie Burns

No abstract provided.


Review Of Searching For Hawa's Secret, John Stephen Brantley Jan 2000

Review Of Searching For Hawa's Secret, John Stephen Brantley

Steve Brantley

No abstract provided.


Avian Prey-Dropping Behavior. I. The Effects Of Prey Characteristics And Prey Loss, Paul V. Switzer, Daniel A. Cristol Jan 1999

Avian Prey-Dropping Behavior. I. The Effects Of Prey Characteristics And Prey Loss, Paul V. Switzer, Daniel A. Cristol

Paul V. Switzer

No abstract provided.


Rejection Of Cowbird Eggs By Mourning Doves: A Manifestation Of Nest Usurpation? Brian D. Peer And Eric K. Bollinger, Eric K. Bollinger, Brian D. Peer Oct 1998

Rejection Of Cowbird Eggs By Mourning Doves: A Manifestation Of Nest Usurpation? Brian D. Peer And Eric K. Bollinger, Eric K. Bollinger, Brian D. Peer

Eric K. Bollinger

This article was printed in The Auk, Volume 115, No.4 (1998).


Effects Of Distance To Juniperus Virginiana On The Establishment Of Fraxinus And Acer Seedlings In Old Fields, Scott J. Meiners, David L. Gorchov Apr 1998

Effects Of Distance To Juniperus Virginiana On The Establishment Of Fraxinus And Acer Seedlings In Old Fields, Scott J. Meiners, David L. Gorchov

Scott J. Meiners

It has been hypothesized that Juniperus virginiana facilitates tree seedling establishment in secondary succession. To test this hypothesis, we sampled four old fields in southwestern Ohio and monitored experimentally planted seeds and seedlings of Acer saccharum and Fraxinus americana for two years. Seeds and seedlings were placed into herbivore exclosures placed 0.3 and 3.0 m from J virginiana trees in an old field in Ohio. We found a significant positive spatial association between juniperus virginiana and tree seedling densities in all four old fields. Soil temperature, soil moisture, evaporative demand and light level in the 0.3 m treatment were significantly …


Reproductive Demographics And Early Life History Of The Shovelnose Sturgeon (Scaphirhynchus Platorynchus), Robert E. Colombo Jan 1998

Reproductive Demographics And Early Life History Of The Shovelnose Sturgeon (Scaphirhynchus Platorynchus), Robert E. Colombo

Robert E. Colombo

Due to the collapse of the historic caviar fisheries in the Volga River and Caspian Sea, the demand on domestically produced caviar has increased. To supply the increased demand, the harvest of the shovelnose sturgeon Scaphirhynchus latorynchus has increased. Because caviar fisheries preferentially harvest females, information regardingthe sexual demographics of these populations is essential for effective fisheries management. To date, knowledge regarding the sex ratios and reproductive development of the shovelnose sturgeon population in the Middle Mississippi River is lacking. In Chapter 1, I describe this problem in detail and in subsequent chapters I explain how I addressed this problem …


Cyperus Fuscus (Cyperaceae), New To Missouri And Nevada, With Comments On Its Occurrence In North America, Paul M. Mckenzie, Brad Jacobs, Charles T. Bryson, Gordon C. Tucker, Richard Carter Jan 1998

Cyperus Fuscus (Cyperaceae), New To Missouri And Nevada, With Comments On Its Occurrence In North America, Paul M. Mckenzie, Brad Jacobs, Charles T. Bryson, Gordon C. Tucker, Richard Carter

Gordon C. Tucker

No abstract provided.


Improving Recovery Planning For Threatened And Endangered Species, Theodore C. Foin, Seth P. Riley, Anitra L. Pawley, Debra R. Ayres, Tina M. Carlsen, Peter J. Hodum, Paul V. Switzer Jan 1998

Improving Recovery Planning For Threatened And Endangered Species, Theodore C. Foin, Seth P. Riley, Anitra L. Pawley, Debra R. Ayres, Tina M. Carlsen, Peter J. Hodum, Paul V. Switzer

Paul V. Switzer

No abstract provided.


Egg Removal By Brown-Headed Cowbirds: A Field Test Of The Host Incubation Efficiency Hypothesis, Douglas R. Wood, Eric K. Bollinger Nov 1997

Egg Removal By Brown-Headed Cowbirds: A Field Test Of The Host Incubation Efficiency Hypothesis, Douglas R. Wood, Eric K. Bollinger

Eric K. Bollinger

Brown-headed Cowbirds (Molothrus ater) often remove host eggs, usually to the detriment of the host's reproductive success. We tested the hypothesis that host egg size and number influence the incubation efficiency of a parasitic egg. A single House Sparrow (Passer domesticus) or Brown-headed Cowbird egg was placed in each host nest (addition), and in some nests a host egg was removed as well (addition/removal). Hatching success and incubation length were measured to determine whether host-egg removal conferred an advantage in incubation efficiency compared to simple addition of a parasitic egg. Redwinged Blackbirds (Agelaius phoeniceus) and Chipping Sparrows (Spizella passerina) served …


Explanations For The Infrequent Cowbird Parasitism On Common Grackles, Brian D. Peer, Eric K. Bollinger Feb 1997

Explanations For The Infrequent Cowbird Parasitism On Common Grackles, Brian D. Peer, Eric K. Bollinger

Eric K. Bollinger

We determined the factors responsible for the lack of parasitism on Common Grackles (Quiscalus quiscula) by Brown-headed Cowbirds (Molothrus ater). We found no evidence of parasitism on the 401 grackle nests we monitored in east-central Illinois. By the time cowbirds began laying eggs, 88.5% of all grackle nests were beyond the point of successful parasitism. Grackles rejected cowbird eggs more frequently during the prelaying stage of the nesting cycle (38.2%) compared to later stages (12.3%). Thirty-three cowbird eggs and nestlings were cross-fostered into grackle nests. Data were collected on 15 cowbird nestlings, of which three fledged. The cross-fostered cowbird eggs …


Comparative Leaf Anatomy And Systematics In Dendrobium, Sections Aporum And Rhizobium (Orchidaceae), Barbara S. Carlsward, William Lois Stern, Walter S. Judd, Terence W. Lucansky Jan 1997

Comparative Leaf Anatomy And Systematics In Dendrobium, Sections Aporum And Rhizobium (Orchidaceae), Barbara S. Carlsward, William Lois Stern, Walter S. Judd, Terence W. Lucansky

Barbara S. Carlsward

The specialized leaf anatomy for species of Dendrobium within section Aporum is similar to that of species in section Rhizobium. In both sections leaves are characterized by a unifacial or nearly unifacial surface where the exposed surface is abaxial. However, leaves in section Rhizobium also feature a lacuna submerged in the mesophyll and surrounded by an adaxial epidermis. In contrast, leaves in section Aporum merely present an internal suture that divides the leaf into bilateral halves. These two sections of Dendrobium are hypothesized to be sister taxa because of synapomorphies in their foliar anatomy. A cladistic analysis performed with various …


Selective Predation On The Seeds Of Woody Plants, Scott J. Meiners, Edmund W. Stiles Jan 1997

Selective Predation On The Seeds Of Woody Plants, Scott J. Meiners, Edmund W. Stiles

Scott J. Meiners

Selective predation on the seeds of woody plants. J. Torrey Bot. Soc. 124: 67-70). 1997.-Seed predation may be an important factor influencing the structure of successional plant communities. We used a cafeteria-style experiment, placed in an old field and an early successional forest, to determine predator preferences for seeds of nine species of woody plants. Intensity of seed predation was equivalent in both sites. Seed predators preferred Acer saccharum, flex vertic illata, and Viburnum dentatum, but this was not related to seed mass. Predation intensity was more variable in the old field than in the forest, possibly related to the …


Crows Do Not Use Automobiles As Nutcrackers: Putting An Oft-Repeated Anecdote To The Test, Daniel A. Cristol, Paul V. Switzer, K L. Johnson, L S. Walke Jan 1997

Crows Do Not Use Automobiles As Nutcrackers: Putting An Oft-Repeated Anecdote To The Test, Daniel A. Cristol, Paul V. Switzer, K L. Johnson, L S. Walke

Paul V. Switzer

No abstract provided.


Successional Changes And Habitat Selection In Hayfield Bird Communities, Eric K. Bollinger Jul 1995

Successional Changes And Habitat Selection In Hayfield Bird Communities, Eric K. Bollinger

Eric K. Bollinger

I examined the effects of successional changes in vegetation on the breeding dispersion of grassland birds in hayfields in New York. I sampled vegetation and counted birds in 90 hayfields of various ages (i.e. number of years since planting) and sizes that were originally planted to a legume-dominated seed mixture. I also resampled a subset of these fields two years later. Over time, these hayfields changed from tall, dense, homogeneous stands of legume-dominated vegetation to short, sparse, patchy stands of grass-dominated vegetation. Fields of all ages were dominated by introduced plant species. Red-winged Blackbirds (Agelaius phoeniceus), the most common bird …


Preliminary Keys To Carex (Cyperaceae) In New York State, Gordon C. Tucker May 1995

Preliminary Keys To Carex (Cyperaceae) In New York State, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


The Soil Seed Pool Of Huffman Prairie, A Degraded Ohio Prairie, And Its Potential In Restoration, Scott J. Meiners, David L. Gorchov Jan 1994

The Soil Seed Pool Of Huffman Prairie, A Degraded Ohio Prairie, And Its Potential In Restoration, Scott J. Meiners, David L. Gorchov

Scott J. Meiners

The germinable seeds in the soil of a relict Ohio prairie were investigated to determine the composition and density of dicots of potential value in restoration. Soil samples were collected from three areas of the prairie with distinctive species compositions: swale, north upland, and south upland. Seed density and species composition were based on seedling emergence over 90 days. North upland and south upland samples yielded similar total seedling densities (5,902 and 5,109 m·2 ) while that of the swale was greater ( 15,262 m·2 ). Thirteen introduced and 18 native dicot species were present; seven of the latter were …


Flora Of An Unusually Diverse Old Growth Forest In The Southeastern Adirondacks, Gordon C. Tucker, Richard S. Mitchell Jan 1994

Flora Of An Unusually Diverse Old Growth Forest In The Southeastern Adirondacks, Gordon C. Tucker, Richard S. Mitchell

Gordon C. Tucker

A lowland, virgin white pine-hemlock stand and associated old-growth habitats were studied at Pack Forest Preserve, Warren County, NY. An area of 48.1 acres, interrupted only by nature trails, has white pines up to 58 inches in diameter, and supports 355 native plant species-an unexpectedly high number, considering its location in the climatically severe Adirondack Mountains. This minimally disturbed old-growth forest and its associated wetlands are not only diverse, but essentially weed-free, making them ideal for future ecological research, botanical teaching and monitoring activities.


Fabrication And Characterization Of Thin, Self‐Supporting Germanium Single Crystals, M. W. Grant, P. F. Lyman, J. H. Hoogenraad, Barbara S. Carlsward, D. A. Arms, L. E. Seiberling, F. Namavar Jan 1993

Fabrication And Characterization Of Thin, Self‐Supporting Germanium Single Crystals, M. W. Grant, P. F. Lyman, J. H. Hoogenraad, Barbara S. Carlsward, D. A. Arms, L. E. Seiberling, F. Namavar

Barbara S. Carlsward

Thin Gesingle crystals (≤1 μm) up to 4 mm in diameter have been fabricated from epitaxialGefilmsgrown by atmospheric pressurechemical vapor deposition on Si(100) wafers. The thin Ge windows are formed by chemically etching away both the Si substrate and the region of the Gefilm near the interface that contains misfit dislocations associated with heteroepitaxialgrowth and relaxation of the Gefilms. The resulting Gefilms are comparable in crystalline quality to bulk Ge wafers, as indicated by ion channeling studies.


Sagina Japonica (Sw.) Ohwi, An Overlooked Adventive In The Northeastern United States, Richard S. Mitchell, Gordon C. Tucker Jan 1991

Sagina Japonica (Sw.) Ohwi, An Overlooked Adventive In The Northeastern United States, Richard S. Mitchell, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


Scirpus Polyphyllus (Cyperaceae) In New Hampshire, Gordon C. Tucker Jan 1991

Scirpus Polyphyllus (Cyperaceae) In New Hampshire, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


Tests Of Three Hypotheses Of Hatching Asynchrony In The Common Tern, Patricia B. Bollinger, Eric K. Bollinger, Richard A. Malecki Sep 1990

Tests Of Three Hypotheses Of Hatching Asynchrony In The Common Tern, Patricia B. Bollinger, Eric K. Bollinger, Richard A. Malecki

Eric K. Bollinger

We examined three hypotheses concerning hatching asynchrony in the Common Tern (Sterna hirundo). Survival of third-hatching "C-chicks" was significantly lower than that of "A-" and "B-chicks" in broods of three. In 2 yr when conditions did not appear favorable, survival was significantly higher in manipulated broods in which chicks hatched synchronously (73%) than in nonmanipulated broods (56%). Chicks in synchronous broods grew significantly faster than C-chicks and at a rate similar to A- and B-chicks. These results were inconsistent with the brood-reduction hypothesis, which predicts that hatching asynchrony will maximize brood success under conditions of food limitation. Chicks hatching from …


Achene Microstructure In Eriophorum L. (Cyperaceae): Systematic Implications And Paleobotanical Applications, Gordon C. Tucker, Norton G. Miller Jan 1990

Achene Microstructure In Eriophorum L. (Cyperaceae): Systematic Implications And Paleobotanical Applications, Gordon C. Tucker, Norton G. Miller

Gordon C. Tucker

Silica bodies in the outer cells of the achene epidermis in 17 species of Eriophorum-and nine species of Scirpus, some of which have been placed in Eriophorum, were revealed by sonication and/or acetolysis and examined by scanning electron microscopy. A silica body consists of a basal platform, one or more large elevated protuberances, and sometimes smaller satellite protuberances. Individual species differ in the number of protuberances, the presence/absence of satellites, the texture of the platform, and the occurrence of nodules on the larger protuberances. These features, combined with achene shape and characteristics of the anticlinal walls of the epidermal cells …


The Genera Of Arundinoideae (Gramineae) In The Southeastern United States, Gordon C. Tucker Jan 1990

The Genera Of Arundinoideae (Gramineae) In The Southeastern United States, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


The Effects Of Site Quality On Breeding-Site Fidelity In Bobolinks, Eric K. Bollinger, Thomas A. Gavin Oct 1989

The Effects Of Site Quality On Breeding-Site Fidelity In Bobolinks, Eric K. Bollinger, Thomas A. Gavin

Eric K. Bollinger

We compared breeding-site fidelity of Bobolinks (Dolichonyx oryzivorus) at two low-quality sites (Bald Hill and Shackelton Point, BH +SP) with that at one high-quality site (Moore Road, MR) in central New York. Yearly density of fledglings at Moore Road was more than six times the density at Bald Hill and Shackelton Point. Furthermore, individual residents fledged 50-70% more young at the high-quality site. At Moore Road, 70% of the males and 49% of the females returned one or more times, compared with 44% of the males and 25% of the females at the low-quality sites. Successful residents (i.e. those fledging …


The Genera Of Commelinaceae In The Southeastern United States, Gordon C. Tucker Jan 1989

The Genera Of Commelinaceae In The Southeastern United States, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


The Genera Of Bambusoideae (Gramineae) In The Southeastern United States, Gordon C. Tucker Jan 1988

The Genera Of Bambusoideae (Gramineae) In The Southeastern United States, Gordon C. Tucker

Gordon C. Tucker

No abstract provided.


Microbial Degradation Of Oxalate In The Gastrointestinal Tracts Of Rats, Steven L. Daniel Aug 1987

Microbial Degradation Of Oxalate In The Gastrointestinal Tracts Of Rats, Steven L. Daniel

Steven L. Daniel

Rates of oxalate degradation by mixed bacterial populations in cecal contents from wlld rats ranged from 2.5 to 20.6 µmol/g (dry weight) per h. The oxalate-degrading activity in cecal contents from three strains of laboratory rats (Long-Evans, Wistar, and Sprague-Dawley) from four commercial breeders was generally lower, ranging from 1.8 to 3.5 µmollg (dry weight) of cecal contents per h. This activity did not increase when diets were supplemented with oxalate. Wben Sprague-Pawley rats from a fifth commercial breeder were fed an oxalate diet, rates of oxalate degradation in cecal contents increased from 2.0 to 23.1 µmollg (dry weight) per …