Date of Award:
Doctor of Philosophy (PhD)
Trisha B. Atwood
Trisha B. Atwood
Julie K. Young
Noelle G. Beckman
Seed dispersal by animals is important for the ecology of plants. It is particularly important to understand which animals are involved and how they move seeds differently from one another. Some seed dispersers are understudied despite ample evidence they consume fruits and seeds. This includes animals commonly referred to as carnivores in the order Carnivora. The overall goal of my dissertation was to describe the extent and quality of seed dispersal by Carnivorans, estimate important aspects of seed dispersal for a specific Carnivoran, the coyote, and estimate how differences between a coyote and songbirds affect where plants will occur in the future and if that changes how much carbon plants store on the landscape. To achieve these goals, I first systematically reviewed existing research on frugivory and seed dispersal by Carnivorans. Then, I experimentally evaluated how long it takes for seeds to pass through a coyote, and if the consumption of seeds by coyotes negatively affects seed germination or viability. Finally, I modeled how differences in the distances that coyotes carry seeds vs. songbirds affect plant migrations. I found that Carnivoran frugivory and seed dispersal are common, involve many plant species, and occur worldwide across most ecosystems. Carnivorans also rarely damage seeds or hamper seed viability and germination when they consume and disperse seeds. Furthermore, I found that coyotes generally take between 4 and 24 hours to pass seeds from the fruits they consumed and deliver seeds to new landscapes without harming them. Given coyote travel speeds, these results suggest that coyotes regularly disperse seeds up to 5 km. This seed dispersal distance is substantially greater than songbirds and led to a 2.5 times larger expansion of where junipers grew in models extending 80 years into the future. Coyote seed dispersal would also result in 3.4 times greater conversion of grasslands and an increase total biotic carbon storage by 1.1 Pg. My findings show that understudied seed dispersers like Carnivorans can greatly impact plant ecology and ecosystem services and highlights the need for further studies on the impacts of Carnivora on seed dispersal.
Draper, John P., "Carnivoran Frugivory and its Effect on Seed Dispersal, Plant Community Composition, Migration, and Biotic Carbon Storage" (2022). All Graduate Theses and Dissertations, Spring 1920 to Summer 2023. 8389.
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