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Kelp patch size and density influence secondary productivity and diversity of epifauna


Shelamoff, V and Layton, C and Tatsumi, M and Cameron, MJ and Edgar, GJ and Wright, JT and Johnson, CR, Kelp patch size and density influence secondary productivity and diversity of epifauna, Oikos, 129, (3) pp. 331-345. ISSN 0030-1299 (2019) [Refereed Article]

Copyright Statement

2019 Nordic Society Oikos.

DOI: doi:10.1111/oik.06585


Habitat‐forming ecosystem engineers are the foundation of many marine ecosystems where they support diverse and productive food‐webs. A reduction in their patch size or density may affect the productivity, biodiversity and stability of these ecosystems. We determined the effects of different densities and patch sizes of Ecklonia radiata (the dominant kelp in southern Australia) on the secondary productivity, species richness, diversity and community structure of understory epifaunal invertebrates and how associated environmental covariates modified by kelp affected those patterns. We assessed sub‐canopy epifauna across 28 artificial reefs with transplanted E. radiata consisting of seven different patch sizes (0.127.68 m2) crossed with four kelp densities (016 kelp m−2) over two years. Epifaunal secondary productivity associated with both natural algal and standardised rope fibre habitats decreased with patch size and was elevated when kelp was absent, however, it was also high in natural habitat when there was a high density of kelp. Epifaunal productivity was positively associated with sub‐canopy light and water flow but negatively associated with the biomass of the dominant understory alga, Ulva sp. Epifaunal diversity declined with a reduction in reef size as did richness which correlated with a loss of algal species richness. Community structure of epifauna also differed between small and large reefs, between reefs with and without kelp, between rope habitats at the centre and at the edge of reefs, and within natural habitat between reefs supporting high and low densities of kelp. Overall, these results indicate complex effects of E. radiata decline on epifaunal communities, with high secondary productivity associated with dense kelp stands, but also areas without kelp that are dominated by turf algae. While the loss of standing kelp from rocky reefs may result in declines in epifaunal biodiversity, where turf algae replaces kelp, the reefs may still support high secondary productivity.

Item Details

Item Type:Refereed Article
Keywords:kelp, epifauna, biodiversity, Ecklonia radiata, ecosystem engineer, secondary productivity, turf algae, Ulva, understory algae
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Coastal or estuarine biodiversity
UTAS Author:Shelamoff, V (Mr Victor Shelamoff)
UTAS Author:Layton, C (Dr Cayne Layton)
UTAS Author:Tatsumi, M (Mr Masayuki Tatsumi)
UTAS Author:Cameron, MJ (Mr Matthew Cameron)
UTAS Author:Edgar, GJ (Professor Graham Edgar)
UTAS Author:Wright, JT (Associate Professor Jeffrey Wright)
UTAS Author:Johnson, CR (Professor Craig Johnson)
ID Code:137295
Year Published:2019
Web of Science® Times Cited:6
Deposited By:Ecology and Biodiversity
Deposited On:2020-02-07
Last Modified:2020-03-30

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