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Physical Sciences and Mathematics Commons™

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Natural Resources and Conservation

Louisiana State University

2020

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Seasonal Infilling And Sedimentary Characteristics In Sandy Versus Muddy Coastal Borrow Areas On The Louisiana Continental Shelf, Usa, Matthew Barley Aug 2020

Seasonal Infilling And Sedimentary Characteristics In Sandy Versus Muddy Coastal Borrow Areas On The Louisiana Continental Shelf, Usa, Matthew Barley

LSU Master's Theses

Offshore sand deposits on the Louisiana Continental Shelf, such as inner shelf shoals and buried paleo-river channels, can be excavated to restore beaches and barrier islands that are rapidly deteriorating due to subsidence, sea-level rise and deficits in coastal sediment supply. Presented here is grain size, x-radiograph, and Beryllium-7 (7Be) derived sedimentation rates from multicores (~ 50 cm depth) retrieved from borrow areas (BAs) in contrasting depositional settings, all of which have implications for management of water quality, seafloor sedimentology, and biogeochemistry in proximal areas. Multicores were retrieved in fall 2018 at Caminada BA — a sandy energetic …

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Characterization Of Shallow Subsurface Hydrology In Large Fine-Grained Floodplains, Mary Grace Lemon Jul 2020

Characterization Of Shallow Subsurface Hydrology In Large Fine-Grained Floodplains, Mary Grace Lemon

LSU Doctoral Dissertations

Floodplains are hydrologically dynamic, receiving water from overbank events, hyporheic flows, local precipitation, and regional groundwater sources. These sources are variously important contributors to the heterogeneous floodplain water pool that includes matrix water in soil micropores, mobile water in soil macropores, groundwater below the rooting zone, ephemeral to seasonal surface storage, and permanent surface water features such as oxbow lakes, sloughs, and other secondary channels. All sources may be ecologically relevant for floodplain vegetation, but the exact roles of each source in both controlling soil water and shallow groundwater recharge and in controlling floodplain water drainage are not well understood, …

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Estimating The Onset And Extent Of Dieback Of Phragmites Australis Using The Normalized Difference Vegetation Index And Remotely Sensed Land Cover Classifications, Aimee M. Beaudette Jun 2020

Estimating The Onset And Extent Of Dieback Of Phragmites Australis Using The Normalized Difference Vegetation Index And Remotely Sensed Land Cover Classifications, Aimee M. Beaudette

LSU Master's Theses

Phragmites australis is cosmopolitan plant species with an invasive variety present throughout most of North America. In the Balize Delta, Louisiana, USA, P. australis plays an important role in combatting subsidence, maintaining navigation channels, and protecting interior fish and wildlife habitat from waves and storm surge. In 2016 a dieback of P. australis was reported by wetland managers, coinciding with the appearance of an invasive Asian scale insect (Nipponaclerda biwakoensis), though the specific cause is still unknown. Two previous efforts attempted to identify the onset of dieback conditions met with limited success. Using Landsat images from 1985 to …

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An Ecopath With Ecosim Analysis On Offshore Petroleum Platform Influences On Gulf Of Mexico Red Snapper, Valentin Gomez Apr 2020

An Ecopath With Ecosim Analysis On Offshore Petroleum Platform Influences On Gulf Of Mexico Red Snapper, Valentin Gomez

LSU Master's Theses

Offshore oil and gas platforms have had a significant presence in the Gulf of Mexico since the 1950s. An important secondary function of these structures is that they provide artificial habitat to fisheries, most notably Red snapper. Policy changes intended to reduce the risk associated with aging infrastructure have reduced the number of standing platforms from 4044 to 1867 from 2001 to 2018. The effect this loss of habitat has on Red snapper was tested by creating three scenarios of platform changes and modeling the perturbation from 2005 to 2050. The simulation was accomplished using the ecological model Ecopath with …

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Biogeography Of Biological Control: Spatial Variation In Agent-Host Interactions, Nathan Harms Apr 2020

Biogeography Of Biological Control: Spatial Variation In Agent-Host Interactions, Nathan Harms

LSU Doctoral Dissertations

Management of plant invasions using biological control has the potential to generate spatial patterns which reflect geographic or genetic variation in invader or control agents. Despite its rarity in practice, investigations into the biogeography of interacting species (i.e., plant invader and control agent) in the context of biological control can lend insights into species distribution-abundance patterns and provide predictions for spatial variation in control success. I explored spatial variability in biological control agent-plant interactions using two wetland weed study systems with large geographic distributions: flowering rush (Butomus umbellatus L.) and alligatorweed (Alternanthera philoxeroides (Mart.) Griseb). Through literature and …

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Conservation Potential And Mechanisms Of Avian Decline In Experimentally Fragmented And Regenerating Amazonian Rainforest, Cameron Lee Rutt Mar 2020

Conservation Potential And Mechanisms Of Avian Decline In Experimentally Fragmented And Regenerating Amazonian Rainforest, Cameron Lee Rutt

LSU Doctoral Dissertations

Twenty percent of the Brazilian Amazon has now been deforested, and deforestation rates are increasing. Yet the process of deforestation threatens biodiversity beyond the direct loss of habitat by inducing edge effects and creating forest fragments. In the tropics, among the most vulnerable birds to these human disturbances are a group of insectivorous species that forage on or near the ground. A variety of mechanisms have been proposed to explain these declines, but evidence for these hypotheses remains scare or equivocal. In this study, we examine three proposed mechanisms—physiological constraints to bright light, reduced breeding activity and nest success, and …

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