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

Life Sciences Commons

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

Articles 1 - 6 of 6

Full-Text Articles in Life Sciences

Ecological Factors Affecting Muskellunge (Esox Masquinongy) Reproduction In Midwestern Lakes , Michael Paul Dombeck Jan 1984

Ecological Factors Affecting Muskellunge (Esox Masquinongy) Reproduction In Midwestern Lakes , Michael Paul Dombeck

Retrospective Theses and Dissertations

Natural reproduction of muskellunge Esox masquinongy has failed in many waters that formerly supported self-sustaining populations. Laboratory studies showed high muskellunge egg mortality associated with high biological oxygen demand (BOD) substrates where hypoxic conditions developed at the substrate-water interface. Measured dissolved oxygen concentration (DO) at the substrate-water interface in muskellunge spawning sites in eight midwestern lakes showed that four lakes had high DO (mean, 6.0-8.4 mg/liter) and little microstratification, and support self-sustaining muskellunge populations. The remaining four lakes showed extreme DO microstratification and hypoxia (mean, 0.4-2.4 mg/liter) at the substrate-water interface. Populations of the ...


Effects Of Prescribed Burning On Avian Foraging Ecology And Arthropod Abundance In Sagebrush-Grassland , Brian Mark Winter Jan 1984

Effects Of Prescribed Burning On Avian Foraging Ecology And Arthropod Abundance In Sagebrush-Grassland , Brian Mark Winter

Retrospective Theses and Dissertations

Prescribed burning in western sagebrush-grasslands has been used primarily to eradicate sagebrush (Artemisia spp.) and, consequently, increase the growth of herbaceous vegetation. Although fire has been used commonly, little is known about its effects on nongame birds breeding in sagebrush-grasslands. Furthermore, the effects of sagebrush removal on arthropod abundance and composition are unknown. To assess the effect of prescribed burning on the foraging ecology of sage and Brewer's sparrows, intensive preburn and postburn data were collected. My objectives were: (1) to document effects of prescribed burning on the general feeding behavior, activity budgets, feeding frequency, and foraging patterns of ...


Age-Age Correlations, Trait Correlations, And Wood Property Variation For An Alnus Glutinosa (L.) Gaertn Provenance Study , Terry Lean Robison Jan 1984

Age-Age Correlations, Trait Correlations, And Wood Property Variation For An Alnus Glutinosa (L.) Gaertn Provenance Study , Terry Lean Robison

Retrospective Theses and Dissertations

Age-age (juvenile-mature) correlations for height, diameter-at breast-height (DBH), volume, specific gravity, and fiber length were determined for a 17 year-old Alnus glutinosa (L.) Gaertn. provenance study. The correlations indicated that selection could take place at one-half the rotation age for growth traits, and one-third the rotation age for wood properties. Using early DBH to select for volume at rotation age yielded more gain per year than waiting to select directly for volume at maturity;Trait correlations were positive between growth properties. Correlations between specific gravity and fiber length were mostly positive for single trees, and negative for provenance means. Correlations ...


Genotype X Environment Interaction In European Black Alder (Alnus Glutinosa (L.) Gaertn) , Oghenekome Ukrakpo Onokpise Jan 1984

Genotype X Environment Interaction In European Black Alder (Alnus Glutinosa (L.) Gaertn) , Oghenekome Ukrakpo Onokpise

Retrospective Theses and Dissertations

A subset of 17 provenances from an on-going range-wide provenance study of European black alder (Alnus glutinosa) was evaluated in three locations (Iowa, Illinois and Wisconsin) for growth (total height, height growth rates, diameter and volume) and raw biomass properties (field moisture content, maximum moisture content, specific gravity and stem biomass) as well as leaf tissue nitrogen and flower production;Significant differences were found among provenances for all the traits except bark and field moisture contents. The Iowa location had significantly higher mean performances than either southern Illinois or northern Wisconsin locations. Combined analysis over years and locations showed no ...


The Comparative Effects Of Three Toxic Substances On Bluegill Behavior , Mary Gerard Henry Jan 1984

The Comparative Effects Of Three Toxic Substances On Bluegill Behavior , Mary Gerard Henry

Retrospective Theses and Dissertations

A behavioral bioassay was used to compare the separate toxic effects of sublethal concentrations of methyl parathion, copper sulfate and chlordane on bluegill, Lepomis macrochirus. Ten behaviors were monitored in bluegill hierarchies before and after toxicant introductions. These behaviors encompassed respiratory disruptions, changes in comfort movements and aggression. Hyperactivity and increased frequencies of s-jerks and fin flicks were significant (P (LESSTHEQ) 0.05) in fish exposed to the lowest methyl parathion concentration (0.003 mg/L) used. Respiratory disruptions were significantly (P (LESSTHEQ) 0.01) elevated in bluegill exposed to as low as 0.034 mg/L copper sulfate while ...


Importance Of Backwater Area Confluences To The Fishes And Macroinvertebrates Of The Upper Mississippi River, Pool 13, William A. Sheaffer Jan 1984

Importance Of Backwater Area Confluences To The Fishes And Macroinvertebrates Of The Upper Mississippi River, Pool 13, William A. Sheaffer

Retrospective Theses and Dissertations

No abstract provided.