Impacts of climate change in a global hotspot for temperate marine biodiversity and ocean warming

• Published in: Journal of Experimental Marine Biology and Ecology
• Main Authors: Wernberg, T, Russell, BD, Moore, PJ, Ling, SD, Smale, DA, Campbell, A, Coleman, MA, Steinberg, PD, Kendrick, GA, Connell, SD
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Science Bv 2011
• Subjects: Biological Sciences; Ecology; Marine and Estuarine Ecology (incl. Marine Ichthyology); Ocean acidification
• Online Access: https://doi.org/10.1016/j.jembe.2011.02.021; http://ecite.utas.edu.au/75072

Temperate Australia is a global hotspot for marine biodiversity and its waters have experienced well-aboveglobal average rates of ocean warming. We review the observed impacts of climate change (e.g. warming,ocean acidification, changes in storm patterns) on subtidal temperate coasts in Australia and assess how thesesystems are likely to respond to further change. Observed impacts are region specific with the greatestnumber of species responses attributable to climate change reported in south-eastern Australia, where recentocean warming has been most pronounced. Here, a decline of giant kelp (Macrocystis pyrifera) and polewardrange extension of a key herbivore (sea urchin) and other trophically important reef organisms has occurred.Although, evidence of changes on other coastlines around Australia is limited, we suggest that this is due to alack of data rather than lack of change. Because of the eastwest orientation of the south coast, most ofAustralia's temperate waters are found within a narrow latitudinal band, where any southward movement ofisotherms is likely to affect species across very large areas. Future increases in temperature are likely to resultin further range shifts of macroalgae and associated species, with range contractions and local extinctions tobe expected for species that have their northern limits along the southern coastline. While there is currentlyno evidence of changes attributable to non-temperature related climate impacts, potentially due to a lack oflong-term observational data, experimental evidence suggests that ocean acidification will result in negativeeffects on calcifying algae and animals. More importantly, recent experiments suggest the combined effectsof climate change and non-climate stressors (overharvesting, reduced water quality) will lower the resilienceof temperate marine communities to perturbations (e.g. storms, diseases, and introduced species), many ofwhich are also predicted to increase in frequency and/or severity. Thus climate change is likely to, both byitself and in synergy with other stressors, impose change to southern Australian coastal species, includingimportant habitat-forming algae and the associated ecological functioning of temperate coasts. Managementof local and regional-scale stresses may increase the resistance of temperate marine communities to climatestressors and as such, provides an attractive tool for building resilience in temperate systems.