Recognizing adaptation costs in the Anthropocene

While populations can adapt to rapid environmental change in the Anthropocene, adaptation costs may limit evolutionary rescue, even when standing population genetic variation is high. Here, we argue that adaptation costs are linked to evolutionary trade-offs involving scenario- or system-specific traits that usually promote environmental specialization and species coexistence. Adaptation costs can be cryptic, and are more likely to emerge in populations under fluctuating environments or under multiple stressors. Adaptation costs mediated by ecological processes such as competition and symbiosis can limit population growth and species ranges. We advocate for considering adaptation costs in global change studies to improve predictions of future population responses, biological production, and ecosystem resilience.