Abstract:

Objective: This work aims to explore the relationship between the geographical distribution of Picea koraiensis and climate change and to simulate potential suitable distribution areas of P. koraiensis under climate change during different periods, so as to provide a scientific basis for resource management and the protection of P. koraiensis. Method: Based on data from 59 existing distribution sites of P. koraiensis and 19 climate variables obtained from the WorldClim website, the maximum entropy model (MaxEnt) was used to simulate the suitable distribution areas of P. koraiensis during different time periods: the present, last interglacial (LIG), last glacial maximum (LGM), mid-holocene (MH), and two future climate scenarios (RCP4.5 and RCP8.5) that would cover periods (2050s and 2070s). This paper discussed the main environmental factors that could limit the geographical distribution of P. koraiensis, identified potential biological sanctuaries, and predicted how the distribution of P. koraiensis might change under future climate change scenarios. Result: The prediction result from the MaxEnt model was reliable, and the average AUC values of the training dataset and test dataset were both greater than 0.99, indicating high reliability. Precipitation of warmest quarter (Bio18), temperature seasonality (Bio4) and precipitation seasonality (Bio15) were the main variables that limited the distribution of P. koraiensis, with contribution rates of 40.6%, 28.9% and 24.6%, respectively. The current suitable distribution areas of P. koraiensis included the Great Khingan Mountains, Lesser Khingan Mountains and Changbai Mountains in China. The suitable areas of P. koraiensis during the LIG, LGM and MH periods expanded by 107.78%, 110.28% and 105.25%, respectively. From the LIG to the present, its distribution centre followed a migratory trend toward the southeast, then to the northeast, and then to the southwest. The suitable distribution area of P. koraiensis under the future climate scenario shows a decreasing trend. The suitable area under the RCP4.5-2050s, RCP4.5-2070s, RCP8.5-2050s and RCP8.5-2070s scenarios would decrease to 99.06%, 96.88%, 98.05% and 95.08% compared to the current period, respectively. The highly suitable area shows a fragmented distribution. The population distributed in the hinterland of Changbai Mountains and Lesser Khingan Mountains would be relatively stable. Conclusion: Precipitation has a greater influence on the distribution range of P. koraiensis than temperature. P. koraiensis population has expanded during the LIG and shrunken continuously from the MH into the modern era. Based on population genetic diversity, the prediction of suitable areas and sporopollen fossils, it is speculated that the hinterlands of Changbai Mountains and the Lesser Khingan Mountains are the interglacial refuges for P. koraiensis. During future climate scenarios, the suitable distribution area of P. koraiensis will be reduced, and the distribution centre will migrate to high altitudes and high latitudes. The priority should be given to protecting the marginal populations in the northern to central Great Khingan Mountains, the western part of Changbai Mountains and the northern part of Zhangguangcai Mountains.

Key words: Picea koraiensis, maximum entropy model, climate change, suitable areas.