Southern Ocean food webs provide ecosystem services with significant global value including carbon sequestration, fisheries and the existence of iconic wildlife. These services are underpinned by different energetic pathways including those dominated by Antarctic krill, fishes and squids, or gelatinous zooplankton (salps). Climate change is likely to impact Southern Ocean food webs by affecting their foundations — both primary producer communities and ice habitats. However, the implications of these changes for ecosystem services – including wildlife populations, fisheries and carbon sequestration – are unclear, as are the implications for policy and management. Here, we use a generalised representation of Southern Ocean food webs and qualitative network modelling to investigate the consequences of five simple but plausible scenarios of future change for ecosystem services and the conservation of important taxa: (i) a shift in primary producer communities with decreasing large diatoms and increasing small flagellates; (ii) increasing salps; (iii) increase (recovery) of the Great whales; and unregulated and unsustainable fisheries for (iv) krill or (v) toothfish. Strikingly, our results suggest that increases in salps might not have negative consequences for ecosystem services and could enhance carbon export potential. Simulated increases in unregulated krill and toothfish fisheries affect predatory wildlife and could also reduce carbon export potential. Our results emphasise the important policy implications of understanding the structure and change of whole food webs, and highlight that improved quantitative understanding and modelling of the relative importance of different energy pathways will be important for developing robust management responses to climate change impacts.

Item Type:	Refereed Article
Keywords:	ecosystem impacts of climate change, ecosystem management, ecosystem status and trends, marine ecosystem assessment for the Southern Ocean, science-policy, Southern Ocean ecosystems
Research Division:	Environmental Sciences
Research Group:	Climate change impacts and adaptation
Research Field:	Ecological impacts of climate change and ecological adaptation
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Assessment and management of terrestrial ecosystems
UTAS Author:	Trebilco, R (Dr Rowan Trebilco)
UTAS Author:	Melbourne-Thomas, J (Dr Jessica Melbourne-Thomas)
UTAS Author:	Constable, AJ (Dr Andrew Constable)
ID Code:	137529
Year Published:	2020
Web of Science® Times Cited:	18
Deposited By:	CRC-Antarctic Climate & Ecosystems
Deposited On:	2020-02-19
Last Modified:	2020-12-07
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