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Nature. 2019 Jun;570(7759):58-64. doi: 10.1038/s41586-019-1264-6. Epub 2019 Jun 5.

Predator-induced collapse of niche structure and species coexistence.

Author information

1
Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ, USA. rpringle@princeton.edu.
2
Department of Ecology & Evolutionary Biology, Princeton University, Princeton, NJ, USA.
3
Department of Ecology & Evolutionary Biology, Brown University, Providence, RI, USA.
4
Department of Biology, University of Florida, Gainesville, FL, USA.
5
Department of Biology, McGill University, Montreal, Quebec, Canada.
6
Smithsonian Tropical Research Institute, Panama City, Panama.
7
Redpath Museum, McGill University, Montreal, Quebec, Canada.
8
Department of Geology, University of Puget Sound, Tacoma, WA, USA.
9
Department of Ecology & Evolutionary Biology, Cornell University, Ithaca, NY, USA.
10
Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT, USA.
11
Department of Biological Sciences, Rutgers, The State University of New Jersey, Newark, NJ, USA.
12
Department of Zoology, University of Cambridge, Cambridge, UK.
13
Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA.
14
Department of Evolution and Ecology, University of California, Davis, CA, USA.
15
Department of Biology, Washington University, Saint Louis, MO, USA.

Abstract

Biological invasions are both a pressing environmental challenge and an opportunity to investigate fundamental ecological processes, such as the role of top predators in regulating biodiversity and food-web structure. In whole-ecosystem manipulations of small Caribbean islands on which brown anole lizards (Anolis sagrei) were the native top predator, we experimentally staged invasions by competitors (green anoles, Anolis smaragdinus) and/or new top predators (curly-tailed lizards, Leiocephalus carinatus). We show that curly-tailed lizards destabilized the coexistence of competing prey species, contrary to the classic idea of keystone predation. Fear-driven avoidance of predators collapsed the spatial and dietary niche structure that otherwise stabilized coexistence, which intensified interspecific competition within predator-free refuges and contributed to the extinction of green-anole populations on two islands. Moreover, whereas adding either green anoles or curly-tailed lizards lengthened food chainsĀ on the islands, adding both species reversed this effect-in part because the apex predators were trophic omnivores. Our results underscore the importance of top-down control in ecological communities, but show that its outcomes depend on prey behaviour, spatial structure, and omnivory. Diversity-enhancing effects of top predators cannot be assumed, and non-consumptive effects of predation risk may be a widespread constraint on species coexistence.

PMID:
31168105
DOI:
10.1038/s41586-019-1264-6
[Indexed for MEDLINE]

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