Thermal acclimation modulates the impacts of temperature and enrichment on trophic interaction strengths and population dynamics ARNAUD SENTIS 1,2 , JULIE MORISSON 1 andDAVID S. BOUKAL 1,2 1 Faculty of Science, Department of Ecosystem Biology, University of South Bohemia, Brani  sovsk a 31, 370 05  Cesk  e Bud  ejovice, Czech Republic, 2 Laboratory of Aquatic Insects and Relict Ecosystems, Biology Centre CAS, Institute of Entomology, 370 05  Cesk  e Bud  ejovice, Czech Republic Abstract Global change affects individual phenotypes and biotic interactions, which can have cascading effects up to the eco- system level. However, the role of environmentally induced phenotypic plasticity in species interactions is poorly understood, leaving a substantial gap in our knowledge of the impacts of global change on ecosystems. Using a cla- doceran–dragonfly system, we experimentally investigated the effects of thermal acclimation, acute temperature change and enrichment on predator functional response and metabolic rate. Using our experimental data, we next parameterized a population dynamics model to determine the consequences of these effects on trophic interaction strength and food-chain stability. We found that (1) predation and metabolic rates of the dragonfly larvae increase with acute warming, (2) warm-acclimated larvae have a higher maximum predation rate than cold-acclimated ones, and (3) long-term interaction strength increases with enrichment but decreases with both acclimation and acute tem- peratures. Overall, our experimental results show that thermal acclimation can buffer negative impacts of environ- mental change on predators and increase food-web stability and persistence. We conclude that the effect of acclimation and, more generally, phenotypic plasticity on trophic interactions should not be overlooked if we aim to understand the effects of climate change and enrichment on species interaction strength and food-web stability. Keywords: biodiversity loss, climate change, consumer–resource, functional response, metabolic ecology, nonlinear interaction strength, thermal acclimation Received 17 October 2014 and accepted 17 February 2015 Introduction Human activities induce rapid environmental changes that pose a major threat to global biodiversity and ecosystem functioning (Pereira et al., 2010). A crucial challenge is therefore to identify conditions and mecha- nisms that allow species and entire biota to persist and adapt to such changes. Recent studies suggest that evo- lutionary responses are unlikely to rescue species from deteriorating environmental conditions because they are not fast enough (Quintero & Wiens, 2013). Instead, accumulating evidence indicates that phenotypic plas- ticity plays a crucial role in the response and adaptation of species to environmental changes (Chevin et al., 2010; Donelson et al., 2011; Munday et al., 2013). Phenotypic responses to environmental changes are indeed common (Huey et al., 2012), can be transmitted between generations (Donelson et al., 2011), and modu- late individual physiology, morphology and behaviour to cope with change (Donelson et al., 2011; Forster et al., 2012; Huey et al., 2012). Nevertheless, as prior studies focused mainly on individual species, the ecological consequences of phenotypic responses to environmen- tal change for species interactions and ecological communities remain largely unexplored (Gilman et al., 2010; Yang & Rudolf, 2010). Predicting the effects of global warming and other environmental changes on ecological communities is a complex task because species are embedded within communities and their fate depends the consequences of changes in the nature and strength of intraspecific and interspecific interactions (Petchey et al., 1999; Tyli- anakis et al., 2008; Gilbert et al., 2014). Facing this com- plexity, ecologists have been developing a mechanistic framework to identify key processes underlying tem- perature effects on trophic interactions and characterize the impact of global warming on food webs (Binzer et al., 2012; Burnside et al., 2014; Fussmann et al., 2014; Gilbert et al., 2014; Sentis et al., 2014). This framework currently predicts that, over short timescales, warming may destabilize community dynamics by increasing feeding rates. At the same time, metabolic rates often increase faster with temperature than feeding rates (Vu- cic-Pestic et al., 2011; Fussmann et al., 2014; Iles, 2014). Consumers are thereby less energetically efficient at Correspondence: Arnaud Sentis, tel. +420 777 977 095, fax +420 387 775 367, e-mail: asentis@jcu.cz 3290 © 2015 John Wiley & Sons Ltd Global Change Biology (2015) 21, 3290–3298, doi: 10.1111/gcb.12931