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Article
Climate-driven disparities among ecological interactions threaten kelp forest persistence
Global Change Biology
  • Euan J Provost, Southern Cross University
  • Brendan P Kelaher, Southern Cross University
  • Symon A Dworjanyn, Southern Cross University
  • Bayden D Russell, University of Adelaide
  • Sean D Connell, University of Adelaide
  • Giulia Ghedini, University of Adelaide
  • Bronwyn M Gillanders, University of Adelaide
  • WillIAM Figueira, University of Sydney
  • Melinda Coleman, Southern Cross University
Document Type
Article
Publication Date
1-1-2017
Peer Reviewed
Peer-Reviewed
Abstract

The combination of ocean warming and acidification brings an uncertain future to kelp forests that occupy the warmest parts of their range. These forests are not only subject to the direct negative effects of ocean climate change, but also to a combination of unknown indirect effects associated with changing ecological landscapes. Here, we used mesocosm experiments to test the direct effects of ocean warming and acidification on kelp biomass and photosynthetic health, as well as climate-driven disparities in indirect effects involving key consumers (urchins and rock lobsters) and competitors (algal turf). Elevated water temperature directly reduced kelp biomass, while their turf-forming competitors expanded in response to ocean acidification and declining kelp canopy. Elevated temperatures also increased growth of urchins and, concurrently, the rate at which they thinned kelp canopy. Rock lobsters, which are renowned for keeping urchin populations in check, indirectly intensified negative pressures on kelp by reducing their consumption of urchins in response to elevated temperature. Overall, these results suggest that kelp forests situated towards the low-latitude margins of their distribution will need to adapt to ocean warming in order to persist in the future. What is less certain is how such adaptation in kelps can occur in the face of intensifying consumptive (via ocean warming) and competitive (via ocean acidification) pressures that affect key ecological interactions associated with their persistence. If such indirect effects counter adaptation to changing climate, they may erode the stability of kelp forests and increase the probability of regime shifts from complex habitat-forming species to more simple habitats dominated by algal turfs.

Citation Information

Provost, EJ, Kelaher, BP, Dworjanyn, SA, Russell, BD, Connell, SD, Ghedini, G, Gillanders, BM, Figueira, W & Coleman, MA 2017, 'Climate-driven disparities among ecological interactions threaten kelp forest persistence', Global Change Biology, vol. 23, pp. 353-361.

Published version available from:

http://dx.doi.org/10.1111/gcb.13414