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Proc Natl Acad Sci U S A. 2017 Aug 8;114(32):8580-8585. doi: 10.1073/pnas.1700353114. Epub 2017 Jul 17.

An invasive foundation species enhances multifunctionality in a coastal ecosystem.

Author information

1
Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Beaufort, NC 28516; aaron.ramus@gmail.com.
2
Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403.
3
Division of Marine Science and Conservation, Nicholas School of the Environment, Duke University, Beaufort, NC 28516.
4
Marine Ecology Research Group, School of Biological Sciences, University of Canterbury, Christchurch 8041, New Zealand.
5
Oceans Institute and School of Plant Biology, University of Western Australia, Perth, WA 6009, Australia.

Abstract

While invasive species often threaten biodiversity and human well-being, their potential to enhance functioning by offsetting the loss of native habitat has rarely been considered. We manipulated the abundance of the nonnative, habitat-forming seaweed Gracilaria vermiculophylla in large plots (25 m2) on southeastern US intertidal landscapes to assess impacts on multiple ecosystem functions underlying coastal ecosystem services. We document that in the absence of native habitat formers, this invasion has an overall positive, density-dependent impact across a diverse set of ecosystem processes (e.g., abundance and richness of nursery taxa, flow attenuation). Manipulation of invader abundance revealed both thresholds and saturations in the provisioning of ecosystem functions. Taken together, these findings call into question the focus of traditional invasion research and management that assumes negative effects of nonnatives, and emphasize the need to consider context-dependence and integrative measurements when assessing the impact of an invader, including density dependence, multifunctionality, and the status of native habitat formers. This work supports discussion of the idea that where native foundation species have been lost, invasive habitat formers may be considered as sources of valuable ecosystem functions.

KEYWORDS:

biodiversity; conservation; ecosystem engineer; exotic plant; novel facilitation

PMID:
28716918
PMCID:
PMC5558999
DOI:
10.1073/pnas.1700353114
[Indexed for MEDLINE]
Free PMC Article

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