title: Central and rear-edge populations can be equally vulnerable to warming.
abstract: Rear (warm) edge populations are often considered more susceptible to warming than central (cool) populations because of the warmer ambient temperatures they experience, but this overlooks the potential for local variation in thermal tolerances. Here we provide conceptual models illustrating how sensitivity to warming is affected throughout a species' geographical range for locally adapted and non-adapted populations. We test these models for a range-contracting seaweed using observations from a marine heatwave and a 12-month experiment, translocating seaweeds among central, present and historic range edge locations. Growth, reproductive development and survivorship display different temperature thresholds among central and rear-edge populations, but share a 2.5 °C anomaly threshold. Range contraction, therefore, reflects variation in local anomalies rather than differences in absolute temperatures. This demonstrates that warming sensitivity can be similar throughout a species geographical range and highlights the importance of incorporating local adaptation and acclimatization into climate change vulnerability assessments.
authors.affiliation: UWA Oceans Institute (M470) and School of Plant Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.|Department of Environment and Agriculture, Curtin University, Bentley, Western Australia 6102, Australia.
authors.forename: Scott
authors.initials: S
authors.lastname: Bennett
authors.affiliation: UWA Oceans Institute (M470) and School of Plant Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Thomas
authors.identifier: http://orcid.org/0000-0003-1185-9745
authors.initials: T
authors.lastname: Wernberg
authors.affiliation: UWA Oceans Institute (M470) and School of Plant Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Bijo
authors.initials: B
authors.lastname: Arackal Joy
authors.affiliation: UWA Oceans Institute (M470) and School of Plant Biology, University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Thibaut
authors.initials: T
authors.lastname: de Bettignies
authors.affiliation: Evolution and Ecology Research Centre, Centre for Marine Bio-Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia.|Sydney Institute of Marine Sciences, Chowder Bay, New South Wales 2088, Australia.
authors.forename: Alexandra H
authors.initials: AH
authors.lastname: Campbell