Geological Society of America

T228 Ecosystem Engineering through Earth History

Wednesday, 12 October 2022
8:00 AM - 12:00 PM
Mile High Ballroom 3C

THE MISSING PIECES: CHANGES IN THE ECOLOGICAL NICHE OF A MAMMAL COMMUNITY IN NORTH AMERICA OVER THE LATE QUATERNARY

Paper number: T228-13
Program: Technical Sessions
Time: 11:00 AM – 11:15 AM

Authors

Felisa Smith Presenting Author
University of New Mexico, Albuquerque, NM
Emma A. Elliott Smith
United States National Museum of Natural History, Washington, DC
Amelia Villaseñor
University of Arkansas, Fayetteville, AR
Catalina Tomé
University of Nebraska - Lincoln, Lincoln, NE
Catalina Tomé
University of New Mexico, Albuquerque, NM
S. Kathleen Lyons
University of Nebraska - Lincoln, Lincoln, NE
Seth D. Newsome
University of New Mexico, Albuquerque, NM

Abstract

The conservation status of large-bodied mammals is dire. Their decline has serious consequences because they have unique ecological roles, which are not replicated by smaller-bodied animals. Here, we use the fossil record of the megafauna extinction at the terminal Pleistocene to explore the consequences of past biodiversity loss. We characterize the isotopic and body-size niche of a mammal community in Texas before and after the event to assess the influence on the ecology and ecological interactions of surviving species (>1kg). Pre-extinction, a variety of C₄-grazers, C₃-browsers, and mixed-feeders existed, similar to modern African savannas, with likely specialization among the two sabertooth cats for juvenile grazers. Post-extinction, body size and isotopic niche space were lost, and the δ¹³C and δ¹⁵N values of some survivors shifted. We see mesocarnivore release within the Felidae: the jaguar, now an apex carnivore, moved into the specialized isotopic niche previously occupied by extinct cats. Puma, previously absent, became common and lynx shifted towards consuming more C₄-based resources. Lagomorphs were the only herbivores to shift towards C₄resources. Body size changes from the Pleistocene to Holocene were species-specific, with some animals (deer, hare) becoming significantly larger, and others smaller (bison, rabbits) or exhibiting no change to either climate shifts or biodiversity loss. Overall, the Holocene body size-isotopic niche was drastically reduced and considerable ecological complexity was lost. We conclude biodiversity loss led to reorganization of survivors and many ‘missing pieces’ within our community; without intervention, the loss of Earth’s remaining ecosystems that support megafauna will likely suffer the same fate.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-379406

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