Exotic species invasion has been one of the most dramatic ecological event in human history that threatens our economy

public health and ecological integrity.Explaining the nature of the species and species-environment relationship and predicting the spatial distribution of the invasive exotic plants is of great importance for invasive exotic plants prevention and early warning efforts.One approach to species-specific predictions involves the use of habitat-suitability or niche-based models whereby environmental conditions suitable for maintenance of populations of a species are identified and mapped onto geographic space.These approaches combine herbarium specimen locations data with a suite of GIS layers（e.g.climatic

topographic and land cover） to create the ecological models of the species’ requirements.Coupled with these models

GIS can project the ecology model onto geographic space and mapping the habitat-suitability maps in native ranges and exotic ranges.This paper proposes an improved logistic regression approach in an information theoretic framework to predict the suitability of ragweed in both native and invaded ranges.Information-theoretic approaches computed and assessed the modeling choice as well as produced a weighed-average model based on the multiple-models rather than using the sole model with the lowest AIC value or the highest Akaike weight.This multiple-model inference is useful to reduce model selection bias.Having obtained the weighted average model

the resulting regression equations were applied to the native samples including the present points and pseudo-absence points to produce the output of the logit value.Because of lack in true absence data

we didn’t transform the logit value back to regular space scaled from 0—1 representing probability of a pixel containing the species but regard the logit value as the degree of the suitability for the species.So we proposed a new approach specifically to compartmentalize the habitat-suitability using logit value thresholds and frequency statistics.At last

we used this habitat-suitability model developed in native ranges to "project" onto the exotic ranges to predict the ragweed’s potential distribution in China.