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Full-Text Articles in Physical Sciences and Mathematics
Characterization Of Shallow Subsurface Hydrology In Large Fine-Grained Floodplains, Mary Grace Lemon
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, …
Biogeography Of Biological Control: Spatial Variation In Agent-Host Interactions, Nathan Harms
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 …
Conservation Potential And Mechanisms Of Avian Decline In Experimentally Fragmented And Regenerating Amazonian Rainforest, Cameron Lee Rutt
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 …