Determining the impact of key climatic factors on geographic distribution of wild Akebia trifoliate

Abstract

Abstract Based on the first-hand data of field investigation, existing literature, books and plant specimens database resources, the complete and available spatial database of wild Akebia trifoliate in China was established firstly. After analyzing the geographical distribution of Akebia trifoliate and its ecological factors, such as climate, soil and topographic characteristics, based on the existing literature, we selected 16 climatic indicators and used statistical analysis to study key climatic variables affecting its growth from a macro perspective. The results show that: (1) According to the characteristic roots and contribution rate obtained by principal component method, three principal factors are determined. Their corresponding value of three principal factors were 6.0538 and 37.84%, 4.7487 and 29.68%, 3.3822 and 21.14% respectively. All the characteristic roots indicate that the three principal factors are playing a dominant role in climate variables of influencing the distribution of Akebia trifoliate. (2) The first principal factor is called “heat factor”, the most important role determining geographical distribution of Akebia trifoliate, including the variables with larger factor load such as active accumulated temperature (≥10℃), warm index, biological temperature and annual average temperature. It shows that Akebia trifoliate tends to grow in areas with higher heat conditions. The second principal factor is called “humidity factor”, the second role for Akebia trifoliate, including the variables with larger factor load such as evapotranspiration rate, humidity index, annual precipitation, growing season precipitation and relative humidity. So it shows that Akebia trifoliate tends to be in areas with sufficient precipitation and high humidity. The third principal factor is called “illumination factor”, including the variables with larger load such as annual sunshine hours, growing season sunshine hours and extreme low temperature. So Akebia trifoliate likes the areas with relatively short sunshine hours. (3) Heat factor and humidity factor are the main limiting factors for its growth. The significant climatic variables offer a basis for the selection of ecological factors and the determination of weight in the suitability analysis of Akebia trifoliate. These results could provide a theoretical basis for the artificial cultivation of Akebia trifoliate. The ideas and methods for wild Akebia trifoliate in this paper could give a reference for the study of other valuable wild plants.