title: Biological Impacts of Thermal Extremes: Mechanisms and Costs of Functional Responses Matter.
abstract: Thermal performance curves enable physiological constraints to be incorporated in predictions of biological responses to shifts in mean temperature. But do thermal performance curves adequately capture the biological impacts of thermal extremes? Organisms incur physiological damage during exposure to extremes, and also mount active compensatory responses leading to acclimatization, both of which alter thermal performance curves and determine the impact that current and future extremes have on organismal performance and fitness. Thus, these sub-lethal responses to extreme temperatures potentially shape evolution of thermal performance curves. We applied a quantitative genetic model and found that beneficial acclimatization and cumulative damage alter the extent to which thermal performance curves evolve in response to thermal extremes. The impacts of extremes on the evolution of thermal performance curves are reduced if extremes cause substantial mortality or otherwise reduce fitness differences among individuals. Further empirical research will be required to understand how responses to extremes aggregate through time and vary across life stages and processes. Such research will enable incorporating passive and active responses to sub-lethal stress when predicting the impacts of thermal extremes.
authors.affiliation: *University of California, Berkeley, CA, USA 94720 cmw@berkeley.edu.
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Williams
authors.affiliation: University of Washington, Seattle, Washington 98195, USA cmw@berkeley.edu.
authors.forename: Lauren B
authors.initials: LB
authors.lastname: Buckley
authors.affiliation: University of Wyoming, Laramie, WY, USA 82071 cmw@berkeley.edu.
authors.forename: Kimberly S
authors.initials: KS
authors.lastname: Sheldon
authors.affiliation: Station d'Ecologie Théorique et Expérimentale, Moulis, 09200, UMR 5321, CNRS 2 route du CNRS, France cmw@berkeley.edu.
authors.forename: Mathew
authors.initials: M
authors.lastname: Vickers
authors.affiliation: Alfred Wegener Institute, Helmholtz Center for Marine and Polar Research, 27570 Bremerhaven, Germany cmw@berkeley.edu.
authors.forename: Hans-Otto
authors.initials: HO
authors.lastname: Pörtner
authors.affiliation: Loyola Marymount University, Los Angeles, CA, USA 90045 cmw@berkeley.edu.
authors.forename: W Wesley
authors.initials: WW
authors.lastname: Dowd
authors.affiliation: *University of California, Berkeley, CA, USA 94720 San Francisco State University, Tiburon, CA, USA 94132 cmw@berkeley.edu.
authors.forename: Alex R
authors.initials: AR
authors.lastname: Gunderson
authors.affiliation: **University of British Columbia, Vancouver, BC, CanadaV6T 1Z4 cmw@berkeley.edu.
authors.forename: Katie E
authors.initials: KE
authors.lastname: Marshall
authors.affiliation: San Francisco State University, Tiburon, CA, USA 94132 cmw@berkeley.edu.
authors.forename: Jonathon H
authors.initials: JH
authors.lastname: Stillman
mesh_terms: D000064:Acclimatization; D000818:Animals; D005075:Biological Evolution; D057231:Climate Change; D003080:Cold Temperature; D004777:Environment; D006358:Hot Temperature; D007448:Invertebrates / Q000502:physiology*; D014714:Vertebrates / Q000502:physiology*