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Additive And Nonadditive Effects Of Herbivory And Competition On Tree Seedling Mortality, Growth, And Allocation, Scott J. Meiners, Steven N. Handel Jan 2000

Additive And Nonadditive Effects Of Herbivory And Competition On Tree Seedling Mortality, Growth, And Allocation, Scott J. Meiners, Steven N. Handel

Scott J. Meiners

The interaction between simulated cotyledon herbivory and interspecific competition was studied in a greenhouse experiment using two species of trees, Acer rubrum and Quercus palustris, which commonly invade abandoned agricultural fields. Herbivory treatments were applied as a gradient of cotyledon removal for A. rubrum with 0, 25, 50, 75, and 100% of cotyledon tissue removed. Cotyledons from Q. palustris were clipped and removed (control, early, and late removal) to create a gradient of seed reserve availability. The competition treatment consisted of plugs of old-field vegetation that filled the pots with perennial cover. Mortality of seedlings was higher with competition. There …


Mimicking The Scientific Process In The Upper-Division Laboratory, Paul V. Switzer, Walter M. Shriner Jan 2000

Mimicking The Scientific Process In The Upper-Division Laboratory, Paul V. Switzer, Walter M. Shriner

Paul V. Switzer

No abstract provided.


The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz Jan 2000

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz

Paul V. Switzer

No abstract provided.


Predation Rates On Real And Artificial Nests Of Grassland Birds, William B. Davison, Eric K. Bollinger Jan 2000

Predation Rates On Real And Artificial Nests Of Grassland Birds, William B. Davison, Eric K. Bollinger

Eric K. Bollinger

We estimated nesting success at real and artificial nests of grassland birds to test the influence of nest type, nest position, and egg size on predation rates. We distributed wicker nests and realistic woven-grass nests baited with a clay egg and either a Northern Bobwhite (Colinus virginianus) egg or a House Sparrow (Passer domesticus) egg in four grasslands that were part of the Conservation Reserve Program in east-central Illinois. Nesting success averaged 86.5% for 12 days of exposure for artificial nests. For real nests, nesting success was markedly lower, averaging 39% over the entire nesting cycle and 59% during approximately …


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.