Performance in a variable world: using Jensen's inequality to scale up from individuals to populations. Issue 1 (4th September 2019)

• Record Type: Journal Article
• Authors: Denny, Mark
• Editors: Domenici, Paolo
• Is Part Of: Conservation physiology. Volume 7:Issue 1(2019)
• Publication Date: 2019-09-04
• Subjects: Jensen's inequality -- scaling -- temperature variation -- thermal performance curves -- 1/f noise; Nature -- Effect of human beings on -- Periodicals; Conservation biology -- Periodicals; 577.05
• DOI: 10.1093/conphys/coz053
• Languages: English
• ISSNs: 2051-1434

Abstract

Abstract : Body temperature affects plants' and animals' performance, but temperature varies through time within an individual and through space among individuals. Theory developed here predicts that, for an individual, variation reduces performance and contracts the range of viable temperatures. By contrast, variation among individuals reduces performance but increases the viable range. Abstract: Body temperature affects plants' and animals' performance, but these effects are complicated by thermal variation through time within an individual and variation through space among individuals in a population. This review and synthesis describes how the effects of thermal variation—in both time and space—can be estimated by applying a simple, nonlinear averaging scheme. The method is first applied to the temporal variation experienced by an individual, providing an estimate of the individual's average performance. The method is then applied to the scale-dependent thermal variation among individuals, which is modelled as a 1/ f -noise phenomenon. For an individual, thermal variation reduces average performance, lowers the temperature of maximum performance ( Topt ) and contracts the range of viable temperatures. Thermal variation among individuals similarly reduces performance and lowers Topt, but increases the viable range of average temperatures. These results must be viewed with caution, however, because they do not take into account the time-dependent interaction between body temperature and physiological plasticity. Quantifying these interactions is perhaps the largest challenge for ecological and conservation physiologists as they attempt to predict the effects of climate change.