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Full-Text Articles in Life Sciences

Perceptions Of Historical Climate Change And Park Policy: The Impact On The Fremont Cottonwood In Zion National Park, Kathleen Kavarra Corr Mar 2022

Perceptions Of Historical Climate Change And Park Policy: The Impact On The Fremont Cottonwood In Zion National Park, Kathleen Kavarra Corr

Doctoral Dissertations

Despite its “natural” appearance and the Organic Act 1916 mandate for preservation of the natural environment in National Parks, the Virgin River as it flows through Zion National Park’s Zion Canyon was transformed through massive flood control re-engineering projects in the 1930s. The armoring of the river has had significant impacts on riparian vegetation, particularly on the stands of native Fremont Cottonwood trees that once filled the narrow valley. What was the motivation for this massive flood control project carried out in an arid region with less than 15 inches of rain per year? This dissertation explores the motivations which …


Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren Jul 2020

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …


The Effect Of Pruning Treatments On The Vibration Properties And Wind-Induced Bending Moments Of Senegal Mahogany (Khaya Senegalensis) And Rain Tree (Samanea Saman) In Singapore, Daniel Burcham Feb 2020

The Effect Of Pruning Treatments On The Vibration Properties And Wind-Induced Bending Moments Of Senegal Mahogany (Khaya Senegalensis) And Rain Tree (Samanea Saman) In Singapore, Daniel Burcham

Doctoral Dissertations

During pruning, arborists often intend to increase a tree’s resistance to wind loading by selectively removing branches, but there are few studies examining the efficacy of these interventions, especially for large, open-grown trees. In this study, the mass and vibration properties of Senegal mahogany (Khaya senegalensis) and rain tree (Samanea saman) were measured before and after the crowns of trees were incrementally raised or reduced between 0 and 80%. In addition, the wind-induced vibration and bending moments of Senegal mahoganies were monitored before and after the same pruning treatments. For both species, total mass and leaf …


Biology, Molecular Systematics, Population Dynamics And Control Of A Stem Gall Wasp, Zapatella Davisae (Hymenoptera: Cynipidae), Monica Davis Jul 2017

Biology, Molecular Systematics, Population Dynamics And Control Of A Stem Gall Wasp, Zapatella Davisae (Hymenoptera: Cynipidae), Monica Davis

Doctoral Dissertations

Gall wasps are phytophagous insects that often go unnoticed, however, when they are released from their natural enemies, they have the capacity to outbreak and cause extensive foliar damage. One such outbreaking pest, Zapatella davisae, causes significant damage and mortality to black oak, Quercus velutina. In recent years, black oak decline has been documented in Long Island, New York and coastal New England. Little is known about the lifecycle, distribution or population dynamics of Zapatella davisae and the taxonomy of the species is still unclear. My first study described the biology and distribution of Z. davisae. Zapatella …


Improving Conservation Efforts Through A Better Understanding Of Forest Elephant Ecology, The Impacts Of Threats On Elephants And Freshwater Fisheries In Northern Congo, Roger Patrick Boundja Nov 2016

Improving Conservation Efforts Through A Better Understanding Of Forest Elephant Ecology, The Impacts Of Threats On Elephants And Freshwater Fisheries In Northern Congo, Roger Patrick Boundja

Doctoral Dissertations

IMPROVING CONSERVATION EFFORTS THROUGH A BETTER UNDERSTANDING OF FOREST ELEPHANT ECOLOGY, THE IMPACTS OF THREATS ON ELEPHANTS AND FRESHWATER FISHERIES IN NORTHERN SEPTEMBER 2016 ROGER PATRICK BOUNDJA, B.Sc. FORESTRY, MARIEN NGOUABI UNIVERSITY, BRAZZAVILLE MSc. UNIVERSITY OF CAPE TOWN PhD. UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Curtice R. Griffin Catch data, including fish numbers, length-weight were collected during a multi-mesh Gillnet fisheries-independent survey in 2007-2008, and fisheries-dependent mixed gear surveys in 2009-2010 and 2015 across 400km stretch of the Sangha River located in the Sangha Tri-National. Overall, very high species richness (Chao 2 mean=250, SD=16.15) and diversity index (Simpson Inverse …