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Articles 1 - 6 of 6

Full-Text Articles in Life Sciences

Regeneration Ecology Of Oak In Eastern Iowa , Kimberly Dean Coder Jan 1985

Regeneration Ecology Of Oak In Eastern Iowa , Kimberly Dean Coder

Retrospective Theses and Dissertations

Oak (principally Quercus alba L. and Q. rubra L.) regeneration is a major problem in eastern Iowa forests and throughout the central hardwoods. To identify major site and/or species constraints on oak reproduction, 133 one-acre (0.4047 hectare) plots were established, measured, and decribed in seven of the most heavily forested counties of eastern Iowa. Clustering, discrimination, principal component, and stepwise multiple regression multivariate analyses were utilized to isolate reproductive constraints. Additionally, an integration technique to identify potential survival expectations, and a successful modelling technique (corrected for expected survival and checked by Markov chaining), were completed to better understand ...


Soil Autecology Of The Nitrogen-Fixing Microsymbiont, Frankia , Thomas Andrew Permar Jan 1985

Soil Autecology Of The Nitrogen-Fixing Microsymbiont, Frankia , Thomas Andrew Permar

Retrospective Theses and Dissertations

The ability of the Frankia endophyte to infect its host plant may be markedly altered by changes in soil conditions. Plant bioassays showed lowering soil water potential caused significant declines in plant infection rates. Organic matter levels also influenced infection with soils containing zero and high levels of organic matter exhibiting the greatest root nodule formation. The highest infection rates of Frankia occurred at pH 6.0, although these levels were not significantly different within the range of the test. Addition of combined nitrogen to soils had a substantial positive effect on infection rates of Frankia endophyte;Presence of the ...


Raw Material Characterization And Properties Of Structural Flakeboard From Coppice Grown Hybrid Poplar , Paul Michael Winistorfer Jan 1985

Raw Material Characterization And Properties Of Structural Flakeboard From Coppice Grown Hybrid Poplar , Paul Michael Winistorfer

Retrospective Theses and Dissertations

Tree growth variables and properties of the wood and bark were evaluated for 3-year-old coppice grown hybrid poplar. Three clones (NE-5323, NE-5326, and NE-5377) from a Populus x euramericana cross, each growing at 5,000, 10,000, and 15,000 stems/ha were studied. This material was then used for the manufacture of 40 lb/ft('3) homogeneous flakeboards in an attempt to evaluate the effects of the raw material quality on properties of flakeboard;Height, diameters at one foot and 4.5 feet, the proportions of stem and branch material, and the number of sprouts per stump were significantly ...


Anatomy And Physiology Of Sugar Maple (Acer Saccharum March) Seedlings Uninoculated Or Inoculated With The Vesicular-Arbuscular Endomycorrhizal Fungus Glomus Etunicatum , William Jesse Yawney Jan 1985

Anatomy And Physiology Of Sugar Maple (Acer Saccharum March) Seedlings Uninoculated Or Inoculated With The Vesicular-Arbuscular Endomycorrhizal Fungus Glomus Etunicatum , William Jesse Yawney

Retrospective Theses and Dissertations

Mycorrhizal inoculation improved the phosphorus (P) nutrition of sugar maple seedlings in the law P study soil. This improved P nutrition was not translated into growth, however. This was interpreted as evidence for the fungal carbohydrate drain or, perhaps, a threshold level of P needed for shoot growth was not reached in the low P soil even with the improved nutrition attributed to the fungus. In addition, inoculation reduced plant carbohydrate levels in the fall and affected the levels of various nutrients in plant parts. It was proposed that a more efficient endophyte, in terms of its effect on P ...


Predator-Avoidance Behaviors Of White-Tailed Deer That Favor Fawn Survival , Craig Norman Huegel Jan 1985

Predator-Avoidance Behaviors Of White-Tailed Deer That Favor Fawn Survival , Craig Norman Huegel

Retrospective Theses and Dissertations

A study of white-tailed deer (Odocoileus virginianus) fawn mortality and behaviors that influence success of the fawn's hider strategy was conducted in south-central Iowa, 1980-83, and a fawn capture method was developed that relies on monitoring movement patterns of radio-collared adult does during the parturition period. The fawn capture method was more efficient than previously used methods because it was less influenced by habitat and fawn density. Finite mortality rate of Iowa deer fawns was 27% at 180 days postpartum and nearly 75% of total mortality was the result of predation. Coyotes (Canis latrans) caused nearly 67% of the ...


Status And Ecology Of The Brown Pelican In The Greater Puerto Rican Bank Region , Jaime Agustin Collazo Jan 1985

Status And Ecology Of The Brown Pelican In The Greater Puerto Rican Bank Region , Jaime Agustin Collazo

Retrospective Theses and Dissertations

The endangered Caribbean brown pelican (Pelecanus occidentalis occidentalis) was studied in the Greater Puerto Rican Bank from September 1980 to July 1983. Pelican numbers in Puerto Rican coastal waters averaged 1996 annually. Winter populations in Puerto Rico were 25% to 30% larger than summer populations because of an influx of newly fledged young and post-breeding adults from the U.S. Virgin Islands. Estimated mean annual pelican population size in the Bank region is 2300. Yearlings, subadults, and non-breeding adults tended to remain in Puerto Rican waters until breeding readiness caused their return to breeding colonies. Roosting and nesting habitat was ...