Epigenetic plasticity is likely to exacerbate climate change vulnerability

Climate change poses a significant threat to global biodiversity. Evolutionary processes, including adaptation and migration, have been integrated to study vulnerability to changing environments. However, the role of plasticity as a source of variation in fitness-related traits remains less explored when assessing climate change vulnerability. Epigenetic modifications can mediate both evolved and plastic responses to environmental change, thereby contributing crucially to species persistence. Here, we estimated the influence of epigenetic plasticity on the responses of threespine stickleback (Gasterosteus aculeatus) to climate change. We showed that vulnerability to projected climates was the greatest if only plastic loci were available to populations; however, the increased vulnerability could be mitigated by short-distance migration. Our study advances beyond current range modelling by incorporating plasticity into predictions of species’ responses to climate change and demonstrates the contrasting roles of different evolutionary processes in shaping responses to projected environments.