Aim

To assess whether observed thermal bounds in species’ latitudinal ranges (i.e., realized thermal niches) can be used to predict patterns of occurrence and abundance changes observed during a marine heatwave, relative to other important life history and functional traits.

Location

Rottnest Island, Western Australia.

Methods

A time series of standardized quantitative surveys of reef fishes spanning 8 years of pronounced ocean temperature change is used to test whether accurate predictions on shifts in species occupancy and abundance are possible using species traits.

Results

Species‐level responses in occurrence and abundance were closely related to the mid‐point of their realized thermal niche, more so than body size, range size or trophic level. Most of the species that disappeared from survey counts during the heatwave were characterized by geographic ranges that did not extend to latitudes with temperatures equivalent to the ocean temperature peak during the heatwave. We thus find support for the hypothesis that current distribution limits are set directly or indirectly by temperature and are highly responsive to ocean temperature variability.

Main conclusions

Our study shows that reef fish community structure can change very quickly when exposed to extreme thermal anomalies, in directions predicted from the realized thermal niche of the species present. Such predictions can thus identify species that will be most responsive to changing ocean climate. Continued warming, coupled with periodic extreme heat events, may lead to the loss of ecosystem services and ecological functions, as mobile species relocate to more hospitable climes, while less mobile species may head towards extinction.

Item Type:	Refereed Article
Keywords:	Reef Life Survey, long-term monitoring, reef fish, climate change, citizen science, functional traits, ocean climate, resilience, Species Temperature Index, thermal niche, warming
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Assessment and management of terrestrial ecosystems
UTAS Author:	Day, PB (Mr Paul Day)
UTAS Author:	Stuart-Smith, RD (Dr Rick Stuart-Smith)
UTAS Author:	Edgar, GJ (Professor Graham Edgar)
ID Code:	127232
Year Published:	2018
Web of Science® Times Cited:	39
Deposited By:	Ecology and Biodiversity
Deposited On:	2018-07-18
Last Modified:	2018-11-15
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