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Full-Text Articles in Paleobiology
Human Impacts On Mammal Diversity From The Pleistocene To The Present, Carson P. Hedberg
Human Impacts On Mammal Diversity From The Pleistocene To The Present, Carson P. Hedberg
Biology ETDs
Humans have fundamentally altered the planet’s biodiversity. It is critical to characterize these changes, but also to understand how they impact the structure and function of modern ecosystems. This dissertation investigates how anthropogenically mediated species losses and/or introductions influence ecological function and community structure in mammals across multiple temporal and spatial scales. We found that selective loss of large-bodied mammals over the Late Quaternary has led to severe losses in functional diversity in modern ecosystems, suggesting megafaunal mammals contribute distinct ecological functions. These changes to mammal diversity and distribution over millennia have altered both global patterns in functional diversity and …
Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin M. Schroeder
Ontogenetic Niche Shift As A Driver Of Community Structure And Diversity In Non-Avian Dinosaurs, Katlin M. Schroeder
Biology ETDs
As some of the most charismatic megafauna to ever walk the earth, the physiology, morphology, growth and evolution of non-avian theropods has been studied exhaustively, yet little is understood about their roles in ecosystems as juveniles. For carnivorous megatheropods, which exceed 1,000kg in mass yet hatched from eggs of limited size, the likelihood of utilizing different prey through ontogeny was high, simply by proxy of the immense difference in size between adults and juveniles. We found these ontogenetic niche shifts, evidenced by significantly different dental microwear in Tyrannosaurids, to have excluded dinosaurian mesocarnivores from Mesozoic communities. The few dinosaurian mesocarnivores …
Niche Dynamics Of The Felid Guild Following The Pleistocene Megafaunal Extinction, Nicholas A. Freymueller
Niche Dynamics Of The Felid Guild Following The Pleistocene Megafaunal Extinction, Nicholas A. Freymueller
Biology ETDs
The loss of large carnivores is fundamentally restructuring modern mammal communities. However, large carnivore removal is not exclusively a modern trend. The Pleistocene Megafaunal Extinction (PME) resulted in a near-eradication of hyper-carnivorous felids such as saber-toothed cats. However, it is unclear if smaller surviving meso-felids began to infill this ecological vacuum post-PME. I apply Ecological Niche Modeling (ENM) to test evaluate whether surviving felids filled in vacant niches post-extinction, and hypothesize that they ought to have shown increased niche-overlap patterns with mega-felids post-extinction. I model species’ fundamental niches using a multi-temporal approach, and develop a novel test to model realized …