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Community size structure varies with predator-prey size relationships and temperature across Australian reefs


Coghlan, AR and Blanchard, JL and Heather, FJ and Stuart-Smith, RD and Edgar, GJ and Audzijonyte, A, Community size structure varies with predator-prey size relationships and temperature across Australian reefs, Ecology and Evolution, 12, (4) Article e8789. ISSN 2045-7758 (2022) [Refereed Article]

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© 2021. The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, (, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1002/ece3.8789


Climate change and fisheries exploitation are dramatically changing the abundances, species composition, and size spectra of fish communities. We explore whether variation in ‘abundance size spectra’, a widely studied ecosystem feature, is influenced by a parameter theorized to govern the shape of size-structured ecosystems—the relationship between the sizes of predators and their prey (predator–prey mass ratios, or PPMRs). PPMR estimates are lacking for a vast number of fish species, including at the scale of trophic guilds. Using measurements of 8128 prey items in gut contents of 97 reef fish species, we established predator–prey mass ratios (PPMRs) for four major trophic guilds (piscivores, invertivores, planktivores, and herbivores) using linear mixed effects models. To assess the theoretical predictions that higher community-level PPMRs leads to shallower size spectrum slopes, we compared observations of both ecosystem metrics for ~15,000 coastal reef sites distributed around Australia. PPMRs of individual fishes were remarkably high (median ~71,000), with significant variation between different trophic guilds (~890 for piscivores; ~83,000 for planktivores), and ~8700 for whole communities. Community-level PPMRs were positively related to size spectrum slopes, broadly consistent with theory, however, this pattern was also influenced by the latitudinal temperature gradient. Tropical reefs showed a stronger relationship between community-level PPMRs and community size spectrum slopes than temperate reefs. The extent that these patterns apply outside Australia and consequences for community structure and dynamics are key areas for future investigation.

Item Details

Item Type:Refereed Article
Keywords:coastal ecosystems, community composition, habitat complexity, predation, predator-prey mass ratio, size spectrum
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Population ecology
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Coastal and estuarine systems and management not elsewhere classified
UTAS Author:Coghlan, AR (Dr Amy Coghlan)
UTAS Author:Blanchard, JL (Professor Julia Blanchard)
UTAS Author:Heather, FJ (Dr Freddie Heather)
UTAS Author:Stuart-Smith, RD (Dr Rick Stuart-Smith)
UTAS Author:Edgar, GJ (Professor Graham Edgar)
UTAS Author:Audzijonyte, A (Dr Asta Audzijonyte)
ID Code:150800
Year Published:2022
Deposited By:Ecology and Biodiversity
Deposited On:2022-06-30
Last Modified:2022-11-03
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