title: Evolutionary rescue can be impeded by temporary environmental amelioration.
abstract: Rapid evolutionary adaptation has the potential to rescue from extinction populations experiencing environmental changes. Little is known, however, about the impact of short-term environmental fluctuations during long-term environmental deterioration, an intrinsic property of realistic environmental changes. Temporary environmental amelioration arising from such fluctuations could either facilitate evolutionary rescue by allowing population recovery (a positive demographic effect) or impede it by relaxing selection for beneficial mutations required for future survival (a negative population genetic effect). We address this uncertainty in an experiment with populations of a bacteriophage virus that evolved under deteriorating conditions (gradually increasing temperature). Periodic environmental amelioration (short periods of reduced temperature) caused demographic recovery during the early phase of the experiment, but ultimately reduced the frequency of evolutionary rescue. These experimental results suggest that environmental fluctuations could reduce the potential of evolutionary rescue.
authors.affiliation: Institute for Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.|State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China.
authors.forename: Yi-Qi
authors.initials: YQ
authors.lastname: Hao
authors.affiliation: Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Brockhurst
authors.affiliation: Institute for Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.|Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland.
authors.forename: Owen L
authors.identifier: http://orcid.org/0000-0002-7724-1633
authors.initials: OL
authors.lastname: Petchey
authors.affiliation: State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing, 100875, China.
authors.forename: Quan-Guo
authors.initials: QG
authors.lastname: Zhang
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D001435:Bacteriophages / Q000235:genetics* / Q000502:physiology; D005075:Biological Evolution; D004777:Environment; D053476:Extinction, Biological; D056084:Genetic Fitness; D009154:Mutation; D011156:Population Density; D012641:Selection, Genetic; D013696:Temperature
keywords: Adaptation; demographic recovery; environmental change; evolutionary rescue; experimental evolution; microcosm; virus; warming