Quantification of empirical wedge of thermal safety margins from Integrating within-species variation in thermal physiology into climate change ecology

Accurately forecasting the response of global biota to warming is a fundamental challenge for ecology in the Anthropocene. Within-species variation in thermal sensitivity, caused by phenotypic plasticity and local adaptation of thermal limits is often overlooked in assessments of species responses to warming. Despite this, implicit assumptions of thermal niche conservatism or adaptation and plasticity at the species level, permeate the literature and can have important implications for predictions about warming impacts at a population level. Here we review how these attributes interact with the spatial and temporal context of ocean warming to influence the vulnerability of marine organisms. We identify a broad spectrum of thermal sensitivity among marine organisms, particularly in central and cool-edge populations of species distributions, characterized by generally low-sensitivity in organisms with conserved thermal niches, to high sensitivity for organisms with locally adapted thermal niches. Important differences in thermal sensitivity among marine taxa suggest that warming may adversely affect benthic primary producers sooner than less vulnerable higher trophic groups. Embracing the spatial, temporal and biological context of within-species variation in thermal physiology helps explain observed impacts of ocean warming and can improve forecasts about climate change vulnerability in marine systems.This article is part of the theme issue ‘Physiological diversity and global patterns of biodiversity in a time of global climate change: testing and generating key hypotheses involving temperature and oxygen’.