Predator-induced collapse of niche structure and species coexistence
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 l...
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| Published in: | Nature (London) Vol. 570; no. 7759; pp. 58 - 64 |
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| Main Authors: | , , , , , , , , , , , , , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
London
Nature Publishing Group UK
01-06-2019
Nature Publishing Group |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | 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 chains 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.
Whole-ecosystem manipulations of Caribbean islands occupied by brown anoles, involving the addition of competitors (green anoles) and/or top predators (curly-tailed lizards), demonstrate that predator introductions can alter the ecological niches and destabilize the coexistence of competing prey species. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0028-0836 1476-4687 |
| DOI: | 10.1038/s41586-019-1264-6 |