Low potential for evolutionary rescue from climate change in a tropical fish

Morgan, R. , Finnøen, M. H., Jensen, H., Pélabon, C. and Jutfelt, F. (2020) Low potential for evolutionary rescue from climate change in a tropical fish. Proceedings of the National Academy of Sciences of the United States of America, 117(52), pp. 33365-33372. (doi: 10.1073/pnas.2011419117) (PMID:33318195) (PMCID:PMC7776906)

Abstract

Climate change is increasing global temperatures and intensifying the frequency and severity of extreme heat waves. How organisms will cope with these changes depends on their inherent thermal tolerance, acclimation capacity, and ability for evolutionary adaptation. Yet, the potential for adaptation of upper thermal tolerance in vertebrates is largely unknown. We artificially selected offspring from wild-caught zebrafish ( ) to increase (Up-selected) or decrease (Down-selected) upper thermal tolerance over six generations. Selection to increase upper thermal tolerance was also performed on warm-acclimated fish to test whether plasticity in the form of inducible warm tolerance also evolved. Upper thermal tolerance responded to selection in the predicted directions. However, compared to the control lines, the response was stronger in the Down-selected than in the Up-selected lines in which evolution toward higher upper thermal tolerance was slow (0.04 ± 0.008 °C per generation). Furthermore, the scope for plasticity resulting from warm acclimation decreased in the Up-selected lines. These results suggest the existence of a hard limit in upper thermal tolerance. Considering the rate at which global temperatures are increasing, the observed rates of adaptation and the possible hard limit in upper thermal tolerance suggest a low potential for evolutionary rescue in tropical fish living at the edge of their thermal limits.

• Item Type: Articles
• Keywords: CTmax, artificial selection, asymmetrical response, global warming, teleost.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Morgan, Miss Rachael
• Authors: Morgan, R., Finnøen, M. H., Jensen, H., Pélabon, C., and Jutfelt, F.
• College/School: College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• Publisher: National Academy of Sciences
• ISSN: 0027-8424
• ISSN (Online): 1091-6490
• Published Online: 14 December 2020