title: Large carnivores make savanna tree communities less thorny.
abstract: Understanding how predation risk and plant defenses interactively shape plant distributions is a core challenge in ecology. By combining global positioning system telemetry of an abundant antelope (impala) and its main predators (leopards and wild dogs) with a series of manipulative field experiments, we showed that herbivores' risk-avoidance behavior and plants' antiherbivore defenses interact to determine tree distributions in an African savanna. Well-defended thorny Acacia trees (A. etbaica) were abundant in low-risk areas where impala aggregated but rare in high-risk areas that impala avoided. In contrast, poorly defended trees (A. brevispica) were more abundant in high- than in low-risk areas. Our results suggest that plants can persist in landscapes characterized by intense herbivory, either by defending themselves or by thriving in risky areas where carnivores hunt.
authors.affiliation: Department of Zoology, University of British Columbia, Vancouver, BC, Canada. Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. atford@zoology.ubc.ca.
authors.forename: Adam T
authors.initials: AT
authors.lastname: Ford
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA.
authors.forename: Jacob R
authors.initials: JR
authors.lastname: Goheen
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya.
authors.forename: Tobias O
authors.initials: TO
authors.lastname: Otieno
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Department of Anthropology, University of California, Davis, CA, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Bidner
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Department of Anthropology, University of California, Davis, CA, USA.
authors.forename: Lynne A
authors.initials: LA
authors.lastname: Isbell
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Department of Biology, University of Florida, Gainesville, FL, USA.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Palmer
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa.
authors.forename: David
authors.initials: D
authors.lastname: Ward
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Institute of Zoology, Zoological Society of London, Regent's Park, London, UK.
authors.forename: Rosie
authors.initials: R
authors.lastname: Woodroffe
authors.affiliation: Mpala Research Centre, Post Office Box 555, Nanyuki, Kenya. Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Pringle
mesh_terms: D000045:Acacia; D000818:Animals; D000866:Antelopes; D046028:Canidae; D020387:Food Chain; D040362:Geographic Information Systems; D060434:Herbivory; D046009:Panthera; D011235:Predatory Behavior; D014197:Trees