Climate‐driven shift in coral morphological structure predicts decline of juvenile reef fishes. (14th December 2019)

• Record Type: Journal Article
• Authors: Fontoura, Luisa; Zawada, Kyle J. A.; D'agata, Stephanie; Álvarez‐Noriega, Mariana; Baird, Andrew H.; Boutros, Nader; Dornelas, Maria; Luiz, Osmar J.; Madin, Joshua S.; Maina, Joseph M.; Pizarro, Oscar; Torres‐Pulliza, Damaris; Woods, Rachael M.; Madin, Elizabeth M. P.
• Is Part Of: Global change biology. Volume 26:Number 2(2020)
• Page Start: 557
• Page End: 567
• Publication Date: 2019-12-14
• Subjects: body size -- climate change -- community ecology -- coral reefs -- habitat structure -- morphological traits; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.14911
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Rapid intensification of environmental disturbances has sparked widespread decline and compositional shifts in foundation species in ecosystems worldwide. Now, an emergent challenge is to understand the consequences of shifts and losses in such habitat‐forming species for associated communities and ecosystem processes. Recently, consecutive coral bleaching events shifted the morphological makeup of habitat‐forming coral assemblages on the Great Barrier Reef (GBR). Considering the disparity of coral morphological growth forms in shelter provision for reef fishes, we investigated how shifts in the morphological structure of coral assemblages affect the abundance of juvenile and adult reef fishes. We used a temporal dataset from shallow reefs in the northern GBR to estimate coral convexity (a fine‐scale quantitative morphological trait) and two widely used coral habitat descriptors (coral cover and reef rugosity) for disentangling the effects of coral morphology on reef fish assemblages. Changes in coral convexity, rather than live coral cover or reef rugosity, disproportionately affected juvenile reef fishes when compared to adults, and explained more than 20% of juvenile decline. The magnitude of this effect varied by fish body size with juveniles of small‐bodied species showing higher vulnerability to changes in coral morphology. Our findings suggest that continued large‐scale shifts in the relative abundance of morphological groups within coral assemblages are likely to affect population replenishment and dynamics of future reef fish communities. The different responses of juvenile and adult fishes according to habitat descriptors indicate that focusing on coarse‐scale metrics alone may mask fine‐scale ecological responses that are key to understand ecosystem functioning and resilience. Nonetheless, quantifying coral morphological traits may contribute to forecasting the structure of reef fish communities on novel reef ecosystems shaped by climate change. Abstract : We investigated the responses of reef fishes to changes in the morphological structure of coral assemblages following coral bleaching. Temporal changes in coral morphology were captured using a continuous fine‐scale morphological trait, coral convexity. Juvenile reef fish density declined with increased coral convexity (i.e., higher dominance of less complex coral growth forms). In particular, juveniles of small‐bodied fishes showed higher vulnerability to changes in coral morphology. Our findings suggest that linking coral morphological forms to ecosystem functions may contribute to forecasting how reef fish communities might fare under novel marine ecosystems induced by future climate change.