| There are forty species in Amaranthus in the world and twenty of them are in China. Seventeen species of this genera in China belong to exotic species,of which eleven species are invasive. They damaged xero-crops, fruit trees, tea plants and vegetables. Amaranthus retroflexus L. is the most frequent occurrence with widely distribution, and the most harmful invasive weed among Amaranthus. Twenty-eight environmental factors of three types were selected to predict possible distribution including the climatic factors, the topographic factors and the soil factors. Based on the total number of 4207 herbarium records of Amaranthus retroflexus L. in the global range, the quantitative relationship between the actual global distribution of this weed and the corresponding environmental factors was analyzed. Principal component analysis (PCA) was used to select the key environmental factors that influenced the distribution of the species. Based on these results, the possible central and maximum distribution ranges of Amaranthus retroflexus L. were estimated and compared to its actual geographical distributions. The Genetic Algorithm for Rule-set Prediction(GARP) and Geographic information system(GIS) were used to estimated the possible distribution of eight invasive species of Amaranthus. Based on the relationship between the invasive species in Amaranthus and environmental factors, Cluster analysis was used to divide these eight invasive species in Amaranthus into several groups. Finally, evaluation of GARP model and GIS model's performance were tested based on Receiver Operating Characteristics (ROC) analysis. Results showed that:(1)GIS model's result showed that there are fourteen environmental factors which played important roles in affecting the distribution of Amaranthus retroflexus L. The possible central distribution range located in south of New Zealand, southeast of Australia, several areas in north of South America, northwest and southeast of... |
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