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Living with lions: Spatiotemporal aspects of coexistence in savanna carnivores

Living with lions: Spatiotemporal aspects of coexistence in savanna carnivores
Alexandra Burchard Swanson

2014

Department of Ecology, Evolution, and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, MN 55108, UNITED STATES OF AMERICA.

ABSTRACT

Top predators can suppress their smaller guild members and this can have profound consequences that cascade throughout the larger community. Suppression is mediated primarily through interference competition: (a) direct aggressive interactions, and (b) behavioral avoidance by mesopredators to minimize risks of encountering top predators. These avoidance responses can be costly, especially when they result in large-scale displacement that reduces access of the subordinate species to resources. However, fine-scale avoidance strategies may promote macropredator persistence by minimizing risk without costly large-scale displacement. This dissertation explores the role of behavioral avoidance in driving intraguild predator dynamics. Specifically, I examine how African lions affect spotted hyenas, cheetahs, and African wild dogs in Serengeti National Park, Tanzania. Long-term lion monitoring by the Serengeti Lion Project provides a high-resolution understanding of how lions interact with each other and the landscape; I deployed a large-scale camera trapping survey to collect fine-scale spatial data on the broader carnivore community. Chapter 1 reveals that although lions displace African wild dogs from the landscape and suppress their populations, cheetahs persist with lions through space and time. Chapter 2 validates the camera trapping survey designed to study fine-scale carnivore avoidance and highlights the broad utility of citizen science for similar ecological projects. Chapter 3 applies the camera trapping survey to reveal that fine-scale avoidance does not always translate into costly spatial displacement for subordinate species. Together, these chapters identify large-scale displacement as a key driver of mesopredator suppression and fine-scale avoidance as a key mechanism for mesopredator persistence. This dissertation further establishes new methods to continue exploring community dynamics for long-lived, wide-ranging species.