title: Phenotypic plasticity in life-history traits of Daphnia galeata in response to temperature - a comparison across clonal lineages separated in time.
abstract: Climatic changes are projected to result in rapid adaptive events with considerable phenotypic shifts. In order to reconstruct the impact of increased mean water temperatures during past decades and to reveal possible thermal micro-evolution, we applied a resurrection ecology approach using dormant eggs of the freshwater keystone species Daphnia galeata. To this end, we compared the adaptive response of D. galeata clones from Lake Constance of two different time periods, 1965-1974 ("historical") versus 2000-2009 ("recent"), to experimentally increased temperature regimes. In order to distinguish between genetic versus environmentally induced effects, we performed a common garden experiment in a flow-through system and measured variation in life-history traits. Experimental thermal regimes were chosen according to natural temperature conditions during the reproductive period of D. galeata in Central European lakes, with one additional temperature regime exceeding the currently observable maximum (+2°C). Increased water temperatures were shown to significantly affect measured life-history traits, and significant "temperature × clonal age" interactions were revealed. Compared to historical clones, recent clonal lineages exhibited a shorter time to first reproduction and a higher survival rate, which may suggest temperature-driven micro-evolution over time but does not allow an explicit conclusion on the adaptive nature of such responses.
authors.affiliation: Biodiversity and Climate Research Centre Georg-Voigt-Straße 14-1660325 Frankfurt/Main Germany; Institute for Environmental Sciences University Koblenz-Landau Fortstraße 776829 Landau in der Pfalz Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Henning-Lucass
authors.affiliation: University of Hamburg, Biozentrum Grindel Martin-Luther-King Platz 3 20146 Hamburg Germany.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Cordellier
authors.affiliation: Biodiversity and Climate Research Centre Georg-Voigt-Straße 14-1660325 Frankfurt/Main Germany; Department of Ecology and Evolution Frankfurt University Max-von-Laue-Straße 1360438 Frankfurt am Main Germany.
authors.forename: Bruno
authors.initials: B
authors.lastname: Streit
authors.affiliation: Biodiversity and Climate Research Centre Georg-Voigt-Straße 14-1660325 Frankfurt/Main Germany; Institute for Environmental Sciences University Koblenz-Landau Fortstraße 776829 Landau in der Pfalz Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schwenk
keywords: Climate change; Daphnia; freshwater ecosystems; life‐history traits; micro‐evolution; resurrection ecology