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Contributions of an annual invasive kelp to native algal assemblages: algal resource allocation and seasonal connectivity across ecotones


Jimenez, RS and Hepburn, CD and Hyndes, GA and McLeod, RJ and Hurd, CL, Contributions of an annual invasive kelp to native algal assemblages: algal resource allocation and seasonal connectivity across ecotones, Phycologia, 54, (5) pp. 530-544. ISSN 0031-8884 (2015) [Refereed Article]

Copyright Statement

Copyright 2015 International Phycological Society

DOI: doi:10.2216/15-39.1


The consequences of macroalgal invasions for coastal ecosystem structure and food webs remain poorly understood. We investigated the relative contribution of the invasive kelp Undaria pinnatifida (Heterokontophyta), which has an annual life cycle, to the composition of algal assemblages in subtidal rocky reefs and in the wrack of nearby surf zones and sandy beaches in southern New Zealand. Undaria pinnatifida made substantial contributions to the density and percent cover (up to 75%) of algal communities in the subtidal habitats studied, suggesting that it influences the living habitat and food resources in subtidal temperate reefs. In comparison, its contribution to the drift in the surf zone and algal wrack that accumulated on sandy beach habitats was low (usually < 25%) compared with native kelps, although it occasionally contributed up to 75% of the drift biomass. This difference likely reflects the lack of buoyancy of U. pinnatifida compared with native kelp species, limiting its capacity to act as a vector for the transfer of carbon across coastal landscapes. In contrast to the native perennial algae, U. pinnatifida's contribution to algal communities in subtidal habitats was inconsistent through time, with the greatest percent cover in early summer (December) and the lowest in early winter (April). Such a temporal pattern in the biomass of wrack and drift U. pinnatifida in beach and surf-zone habitats was, however, less apparent. Our findings suggest that the strongly seasonal and highly invasive U. pinnatifida has the potential to influence carbon fluxes and faunal communities in subtidal food webs, but that such effects are unlikely to be transferred across coastal habitats.

Item Details

Item Type:Refereed Article
Keywords:invasive algae, seaweed, Undaria
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Adaptation to climate change
Objective Field:Ecosystem adaptation to climate change
UTAS Author:Hurd, CL (Professor Catriona Hurd)
ID Code:104206
Year Published:2015
Web of Science® Times Cited:14
Deposited By:IMAS Research and Education Centre
Deposited On:2015-11-04
Last Modified:2017-10-31

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