Dominant factors
Any organisms cannot live without its biotic and abiotic elements around. Their distribution range was determined with many factors, such as climate, soil, topography, biology, history, human activity and so on. A. annua was no exception. In our study, 19 bioclimatic factors and altitude were prepared for distribution modeling. After analyzing their correlations between each other, seven variables were considered to build species distribution models for A. annua . Due to their different basic theories and emphases, the same factors behaved diversely. But BIO9 (mean temperature of driest quarter) occupied the leading position in every models. This bioclimatic variable played an important role in shaping the distribution of A. annua.