Climatic suitable area analysis and response to climate change of Actinidia arguta in China

Actinidia arguta is suitable for growing in a cool and humid environment. Compared with other species, A. arguta has higher nutritional and medicinal value and is also resistant to diseases, pests, drought, and cold. Determining a climactically suitable area for A. arguta may provide a reference for its investigation, protection, development, utilization, and cultivation in China. The MaxEnt (maximum entropy model) and ArcGIS (geographic information system) were used to study the key environmental factors and value range affecting the distribution of A. arguta. Predictions for suitable areas were performed under current and future climate scenarios. Environmental factors were tested for significance (via Jackknife), correlations were determined (via Pearson correlation coefficient), and six key environmental factors affecting the distribution of A. arguta were found (listed in order of significance): precipitation in July > mean temperature in April > temperature seasonality > mean temperature in March > precipitation during the warmest quarter > altitude. Presently, the total highly-suitable area is 9.287×10⁵ km² and is concentrated in the east of Southwest China, the west of Central China, the southeast of North China, the north and southeast of East China, and the southeast of Northeast China. The total moderately suitable area, distributed around the highly suitable area, is 1.786×10⁶ km². Representative concentration pathways (RCP) (i.e., future climate scenarios) predicted that the highly suitable areas will increase (RCP2.6=3.758×10⁵ km², RCP4.5=1.725×10⁵ km², and RCP8.5=6.300×10³ km²), the moderately suitable areas will decrease in the RCP2.6 by 1.902×10⁵ km², while it will increase in the RCP4.5 and RCP8.7 (RCP4.5=2.617×10⁵ km², and RCP8.5=9.760×10⁴ km²). In the RCP2.6 and RCP4.5 scenarios, the geometric center of the highly suitable areas and the total suitable areas will move to the northeast by the 2070s. In the RCP8.5 scenario, the geometric center of the highly suitable areas will move to the northeast, but the geometric center of the total suitable area will move to the southeast by the 2070s. The MaxEnt model was used to predict suitable cultivation areas for A. arguta in the present day and future climate scenarios. All of the 'area under the curve' (AUC) averages were higher than 0.98, indicating high reliability of the predicted model results.