Abstract: Climate-adaptive assisted gene flow (AGF) is a new conservation strategy that leverages ecotypic variation to increase a species’ resilience to future climate. AGF often entails translocations that match source site historical climate with recipient site projected climate. However, transplants may need to survive a lag period before the recipient site becomes climatically suitable. For species with long times to reproductive maturity, current establishment of juveniles could create more climate-resilience future adult populations. Yet, unsuccessful translocations would waste important conservation resources. Few field studies have tested climate-adaptive assisted gene flow on non-timber species. For the endemic California blue oak (Quercus douglasii), we present five years of data on assisted gene flow trials. We translocated seed from 9 populations at the species xeric distributional edge into 12 common gardens at more mesic sites, one with experimental watering and rainout treatments. We measured growth, survival, leaf disease, leaf herbivory and leaf desiccation annually. Seedlings from xeric edge sites showed significant differences from locals, including slower growth and lower survival, but these differences were minimized over time, with highest transplant losses experienced during the first-year. Such long-term studies on assisted gene flow are critical to informing emerging climate-adaptive management.
