Critical indirect effects of climate change on sub-A ntarctic ecosystem functioning

Allan, E Louise; Froneman, P William; Durgadoo, Jonathan V; McQuaid, Christopher D; Ansorge, Isabelle J; Richoux, Nicole B

Title: Critical indirect effects of climate change on sub-A ntarctic ecosystem functioning
Creator: Allan, E Louise
Creator: Froneman, P William
Creator: Durgadoo, Jonathan V
Creator: McQuaid, Christopher D
Creator: Ansorge, Isabelle J
Creator: Richoux, Nicole B
Subject: To be catalogued
Date Issued: 2013
Date: 2013
Type: text
Type: article
Identifier: http://hdl.handle.net/10962/457934
Identifier: vital:75696
Identifier: xlink:href="https://doi.org/10.1002/ece3.678"
Description: Sub‐Antarctic islands represent critical breeding habitats for land‐based top predators that dominate Southern Ocean food webs. Reproduction and molting incur high energetic demands that are sustained at the sub‐Antarctic Prince Edward Islands (PEIs) by both inshore (phytoplankton blooms; “island mass effect”; autochthonous) and offshore (allochthonous) productivity. As the relative contributions of these sustenance pathways are, in turn, affected by oceanographic conditions around the PEIs, we address the consequences of climatically driven changes in the physical environment on this island ecosystem. We show that there has been a measurable long‐term shift in the carbon isotope signatures of the benthos inhabiting the shallow shelf region of the PEIs, most likely reflecting a long‐term decline in enhanced phytoplankton productivity at the islands in response to a climate‐driven shift in the position of the sub‐Antarctic Front. Our results indicate that regional climate change has affected the balance between allochthonous and autochthonous productivity at the PEIs. Over the last three decades, inshore‐feeding top predators at the islands have shown a marked decrease in their population sizes. Conversely, population sizes of offshore‐feeding predators that forage over great distances from the islands have remained stable or increased, with one exception. Population decline of predators that rely heavily on organisms inhabiting the inshore region strongly suggest changes in prey availability, which are likely driven by factors such as fisheries impacts on some prey populations and shifts in competitive interactions among predators. In addition to these local factors, our analysis indicates that changes in prey availability may also result indirectly through regional climate change effects on the islands' marine ecosystem. Most importantly, our results indicate that a fundamental shift in the balance between allochthonous and autochthonous trophic pathways within this island ecosystem may be detected throughout the food web, demonstrating that the most powerful effects of climate change on marine systems may be indirect.
Format: computer
Format: online resource
Format: application/pdf
Format: 1 online resource (11 pages)
Format: pdf
Publisher: Wiley
Language: English
Relation: Ecology and Evolution
Relation: Louise Allan, E., William Froneman, P., Durgadoo, J.V., McQuaid, C.D., Ansorge, I.J. and Richoux, N.B., 2013. Critical indirect effects of climate change on sub‐A ntarctic ecosystem functioning. Ecology and Evolution, 3(9), pp.2994-3004
Relation: Ecology and Evolution volume 3 number 9 p. 2994 2013 2045-7758
Rights: Publisher
Rights: Use of this resource is governed by the terms and conditions of the Wiley Library Online Terms of Use Statement (https://onlinelibrary.wiley.com/terms-and-conditions)
Rights: Open Access

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Richoux, Nicole Bertine (Assoc Prof)

McQuaid, Christopher D (Distinguished Professor)

RU DST/NRF SARChI for Marine Ecosystems and Resources

Froneman, Pierre William (Prof)

SDG 15. Life On Land

RU Department of Zoology and Entomology

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