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Retrospective Theses and Dissertations

Environmental Sciences

Natural resource ecology and management

Publication Year

Articles 1 - 9 of 9

Full-Text Articles in Life Sciences

Riparian Land-Use Impacts On Stream Bank Soil And Phosphorus Losses From Grazed Pastures , Mustafa Tufekcioglu Jan 2006

Riparian Land-Use Impacts On Stream Bank Soil And Phosphorus Losses From Grazed Pastures , Mustafa Tufekcioglu

Retrospective Theses and Dissertations

An emerging challenge in watershed-scale research is to quantify the extent of sediment contributed to receiving waters from stream banks versus overland flow from critical source areas, and to develop management strategies to reduce stream bank erosion. The objective of this research was to compare the amounts of sediment and phosphorus loss from critical stream bank source areas to receiving waters via overland flow and stream bank erosion from riparian grazed pasture under different stocking densities (cow-calf pair ha -1). Rainfall simulations were used to calculate sediment and P loads from overland flow from stream-side livestock loafing and access points ...


A Comparative Agroecosystems Analysis Of Soil Water And Root Dynamics Under Six Different Vegetative Cover Types , Greg William Shepherd Jan 2006

A Comparative Agroecosystems Analysis Of Soil Water And Root Dynamics Under Six Different Vegetative Cover Types , Greg William Shepherd

Retrospective Theses and Dissertations

Anthropogenic activities have impacted land management in the Midwest by transforming perennial grasslands and savannas into annual croplands. Agriculturalists presently have a considerable impact on the ecological balance of expansive amounts of land. This study investigates soil water and root dynamics under six different annual and perennial vegetative cover types. Measurement of growing season surface soil moisture showed no significant differences between annual compared to perennial sites. Depth of water uptake determination indicated that buckbrush and oak acquired moisture from deeper depths (5-10 cm to groundwater) than corn and soybean (5-10 to 10-20 cm). Depth of water uptake for sedge ...


Forest Dynamics In Mesic Northern Hardwoods Following Windthrow And Salvage Logging , Katharyn Dianne Derr Jan 2006

Forest Dynamics In Mesic Northern Hardwoods Following Windthrow And Salvage Logging , Katharyn Dianne Derr

Retrospective Theses and Dissertations

Post-disturbance, or salvage, logging is a highly debated topic within natural resource science and management as its effects on forest recovery are not well understood. We examine a 25-year forest response to a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, some of which was salvage logged. Our results show salvage logging affects the rate of vegetation recovery, microtopography, and soil composition within this mixed broad-leaved deciduous and conifer forest. Although salvaged and unsalvaged areas are similar in tree species composition, tree biomass is higher and forest microtopography is more pronounced within the unsalvaged area ...


Anuran Community Structure And Wetland Occupancy Along An Urban-Rural Gradient In Central Iowa, Usa , Finn Cooper Pillsbury Jan 2006

Anuran Community Structure And Wetland Occupancy Along An Urban-Rural Gradient In Central Iowa, Usa , Finn Cooper Pillsbury

Retrospective Theses and Dissertations

Urbanization has been cited as an important factor in worldwide amphibian declines. Although recent work has illustrated the influence of broad-scale ecological patterns and processes on amphibian populations, little is known about the relative importance of wetland habitat and landscape context on the distribution, abundance, and diversity of anurans in urban landscapes. We therefore examined patterns of anuran community structure and wetland occupancy along an urban-rural gradient in central Iowa, USA. Landscape fragmentation had the strongest influence on anuran community structure, influencing most the abundance of species that use upland habitats outside the breeding season. Urban habitat loss and fragmentation ...


Desiccation And Nitrous Oxide Storage Effects On The Recalcitrant Seeds Of Quercus Alba And Q Macrocarpa , Valasia Iakovoglou Jan 2005

Desiccation And Nitrous Oxide Storage Effects On The Recalcitrant Seeds Of Quercus Alba And Q Macrocarpa , Valasia Iakovoglou

Retrospective Theses and Dissertations

Sensitivity to desiccation of recalcitrant seeds of the Leucobalanus subgenus of Quercus poses limitations to successful storage and regeneration efforts. My three studies evaluated different aspects of these problems. The first study investigated the effect of parent tree and seed size on seedling performance and morphology over the first three months of growth for Quercus alba and Quercus macrocarpa. The second study evaluated the effect of nitrous oxide (N2O) on seed storage as measured by seed, seedling, and starch thermal variables. Seeds from both species were placed in containers with one of three treatments: air, 80/20% and 98/2 ...


Riparian Land-Use Impacts On Stream And Gully Bank Soil And Phosphorus Losses With An Emphasis On Grazing Practices , George Nick Zaimes Jan 2004

Riparian Land-Use Impacts On Stream And Gully Bank Soil And Phosphorus Losses With An Emphasis On Grazing Practices , George Nick Zaimes

Retrospective Theses and Dissertations

The tall-grass prairies, wetlands and forests that dominated the Iowa landscape have been replaced by annual row-crops and grass pastures that occupy more than 90% of the landscape today. Because of these changes, water reaches streams and gullies much faster and has led to incised streams and an extensive growth of gully networks. Stream and gully banks are major contributors of non-point source sediment and phosphorus. Reducing these pollutants is a priority to maintaining healthy streams. The objective of this study was to compare stream and gully bank soil and phosphorus losses under different land-use practices in three Iowa regions ...


A Biophysical And Socio-Economic Examination Of The Use Of Shelterbelts For Swine Odor Mitigation , John Charles Tyndall Jan 2003

A Biophysical And Socio-Economic Examination Of The Use Of Shelterbelts For Swine Odor Mitigation , John Charles Tyndall

Retrospective Theses and Dissertations

The use of shelterbelts (trees and shrubs) arranged in strategic designs near and within swine facilities potentially can play a significant incremental role in bio-physically mitigating odor in a socio-economically responsible way thereby reducing social conflict from odor nuisance. Shelterbelts of modest heights (i.e. 20--30 ft) may be ideal for plume interception, disruption, and dilution. Based on available evidence, there are five primary ways that shelterbelts can mitigate livestock odors: (1) Physical interception and capture of odor laden dust by trees/shrubs; (2) Dilution of gas concentrations of odor into the lower atmosphere; (3) Ground deposition of odor laden ...


Spatial And Temporal Scales Of Distribution And Demography In Breeding Songbirds: Implications Of Habitat Fragmentation And Restoration , Robert J. Fletcher Jr. Jan 2003

Spatial And Temporal Scales Of Distribution And Demography In Breeding Songbirds: Implications Of Habitat Fragmentation And Restoration , Robert J. Fletcher Jr.

Retrospective Theses and Dissertations

Tallgrass prairie has declined throughout the midwestern United States during the past two centuries, and migratory birds breeding in these habitats have also experienced precipitous population declines. One conservation strategy used to mitigate the effects of habitat loss and fragmentation is habitat restoration. I studied how both habitat fragmentation and restoration affect songbird populations breeding in grassland and wetland habitats in northern Iowa, 1999--2002. Most grassland birds tended to be less abundant near edges, yet birds avoided woodland edges more so than other types of edges. Edge avoidance could not be explained by changes in habitat structure. For Bobolinks (Dolichonyx ...


Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr. Jan 2003

Genetic And Environmental Effects On Rooting Ability Of Dormant Unrooted Hybrid Poplar Cuttings , Ronald S. Zalesny Jr.

Retrospective Theses and Dissertations

Genotypes with enhanced rooting ability are crucial for deployment of intensively cultured Populus plantations. Rooting of dormant, unrooted cuttings is the first biological prerequisite to stand establishment. The primary objective was evaluating three developmental systems affected by site conditions: lateral and adventitious root ontogenies, root/shoot growth rates, and temperature dependent physiologies. The study tested rooting ability of 21 clones from five taxonomic backgrounds ((Populus deltoides x Populus trichocarpa) x P. deltoides 'BC1'; P. deltoides 'D'; P. deltoides x Populus maximowiczii 'DM'; P. deltoides x Populus nigra 'DN'; P. nigra x P. maximowiczii 'NM') at Ames, Iowa; Waseca, Minnesota; and ...