Intraspecific variation reshapes coral assemblages under elevated temperature and acidity. (9th October 2022)

• Record Type: Journal Article
• Authors: McWilliam, Mike; Madin, Joshua S.; Chase, Tory J.; Hoogenboom, Mia O.; Bridge, Tom C. L.
• Is Part Of: Ecology letters. Volume 25:Number 11(2022)
• Page Start: 2513
• Page End: 2524
• Publication Date: 2022-10-09
• Subjects: adaptation -- community assembly -- coral reefs -- functional traits -- phenotypic plasticity -- physiology; Ecology -- Periodicals; 577
• DOI: 10.1111/ele.14114
• Languages: English
• ISSNs: 1461-023X

Abstract

Abstract: Insights into assemblages that can persist in extreme environments are still emerging. Ocean warming and acidification select against species with low physiological tolerance (trait‐based 'filtering'). However, intraspecific trait variation can promote species adaptation and persistence, with potentially large effects on assemblage structure. By sampling nine coral traits (four morphological, four tissue and one skeletal) along an offshore–inshore gradient in temperature and pH, we show that distantly related coral species undergo consistent intraspecific changes as they cross into warm, acidic environments. Intraspecific variation and species turnover each favoured colonies with greater tissue biomass, higher symbiont densities and reduced skeletal investments, indicating strong filtering on colony physiology within and across species. Physiological tissue traits were highly variable within species and were independent of morphology, enabling morphologically diverse species to cross into sites of elevated temperature and acidity. Widespread intraspecific change can therefore counter the loss of biodiversity and morphological structure across a steep environmental gradient. Abstract : Our results show that distantly related coral species from different families change their traits in a consistent and predictable way across warming, acidifying gradient. We argue that these changes allow an unexpectedly large range of corals to persist in a warm, acidic environment, thereby helping to maintain diversity.