title: Plants adapted to warmer climate do not outperform regional plants during a natural heat wave.
abstract: With ongoing climate change, many plant species may not be able to adapt rapidly enough, and some conservation experts are therefore considering to translocate warm-adapted ecotypes to mitigate effects of climate warming. Although this strategy, called assisted migration, is intuitively plausible, most of the support comes from models, whereas experimental evidence is so far scarce. Here we present data on multiple ecotypes of six grassland species, which we grew in four common gardens in Germany during a natural heat wave, with temperatures 1.4-2.0°C higher than the long-term means. In each garden we compared the performance of regional ecotypes with plants from a locality with long-term summer temperatures similar to what the plants experienced during the summer heat wave. We found no difference in performance between regional and warm-adapted plants in four of the six species. In two species, regional ecotypes even outperformed warm-adapted plants, despite elevated temperatures, which suggests that translocating warm-adapted ecotypes may not only lack the desired effect of increased performance but may even have negative consequences. Even if adaptation to climate plays a role, other factors involved in local adaptation, such as biotic interactions, may override it. Based on our results, we cannot advocate assisted migration as a universal tool to enhance the performance of local plant populations and communities during climate change.
authors: Plant Evolutionary Ecology Institute of Evolution & Ecology University of Tübingen Tübingen Germany.
authors: Anna
authors: A
authors: Bucharova
authors: Department of Community Ecology Helmholtz Centre for Environmental Research-UFZ Halle Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany.
authors: Walter
authors: W
authors: Durka
authors: Restoration Ecology Department of Ecology & Ecosystem Management Technische Universität München München Germany.
authors: Julia-Maria
authors: JM
authors: Hermann
authors: Biodiversity and Ecosystem Research Group Institute of Landscape Ecology University of Münster Münster Germany.
authors: Norbert
authors: N
authors: Hölzel
authors: Department of Community Ecology Helmholtz Centre for Environmental Research-UFZ Halle Germany.
authors: Stefan
authors: S
authors: Michalski
authors: German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig Leipzig Germany.
authors: Johannes
authors: J
authors: Kollmann
authors: Plant Evolutionary Ecology Institute of Evolution & Ecology University of Tübingen Tübingen Germany.
authors: Oliver
authors: O
authors: Bossdorf
keywords: Adaptation to novel environment; assisted migration; climate warming; global change; local adaptation; predictive provenancing