Biology ETDs

Publication Date

Winter 12-11-2020


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 niches in environmental space. I demonstrate that surviving meso-felids did not exhibit meso-carnivore release post-extinction. Niche overlap was greater than expected during the Pleistocene, yet decreased post-extinction. These findings support apex carnivores as keystone species, and suggest that anthropogenic activity is imparting ecosystem forcing on par with the PME.




paleoecology, biogeography, ENM, felid

Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

Felisa Smith

Second Committee Member

Corinne Myers

Third Committee Member

Scott Collins

Fourth Committee Member

Helen Wearing

Included in

Paleobiology Commons