Please join us for a seminar with University of Wyoming’s Professor Jacob Goheen on Tuesday, October 22nd at 4pm in Biology 136. Snacks and drinks will be provided.

Abstract

Ecologists who work in savannas and grasslands often adhere to a non-equilibrial worldview, in which disturbances (fire, drought, catastrophic herbivory) prevent community and ecosystem properties from reaching equilibria. Conversely, many other ecologists view the world through a lens of trophic control, in which tightly coupled consumer-resource interactions stabilize the local abundance, distribution, and diversity of species. Our group has worked to understand whether, how, and why trophic control operates in two savanna ecosystems in central Kenya. I will discuss some of my favorite findings from this body of research. First, I will demonstrate that fear of predation protects trees from a browsing ungulate, thus triggering a trophic cascade through which large carnivores make savanna tree communities less thorny. Next, I will show that a plant defense—ant mutualists—creates virtual monocultures of myrmecophytic trees. By killing these tiny bodyguards over vast landscapes, the recently introduced big-headed ant has transformed savanna bushlands into more open landscapes, thus reshaping interactions among lions, plains zebra, and buffalo. Although African savannas typically are envisioned as textbook examples of non-equilibrial ecosystems, trophic control can interact with non-equilibrial dynamics to shape the abundance, distribution, and diversity of species within this widespread biome.

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We look forward to seeing you there!