Abstract: Using Maxent model and GIS technology, in combination with ecological environment data and actual geographical distribution of four different sources of Fritillariae Cirrhosae Bulbus, the spatial distribution of suitable habitats for different types of Fritillariae Cirrhosae Bulbus was predicted and the grade of habitat suitability was classified. The results showed that altitude was the most important ecological factor driving the habitat suitability of Fritillariae Cirrhosae Bulbus with different sources. The contribution rates of altitude to the habitat suitability of Fritillaria cirrhosaD. Don, Fritillaria przezvalskiiMaxim.,Fritillaria delavayiFranch., andFritillaria unibracteata Hsiao were 38.8%, 44.9%, 51.1%, and 52.6%, respectively. The suitable habitats for Fritillaria cirrhosa D. Don mainly distributed in areas with an altitude of 1850-4550 m, and the suitable habitats for the other three types were in the alpine areas with an altitude of over 2800 m. The most suitable habitats for different sources of Fritillariae Cirrhosae Bulbus were concentrated in Sichuan, Tibet, Gansu, Qinghai, and Yunnan provinces. However, the distribution area and spatial pattern in each province were different. It is necessary to distinguish different sources of Fritillariae Cirrhosae Bulbus when they are introduced, domesticated, and artificially planted.

Key words: annual, maize field in Northeast China, greenhouse gas, emission fluxes, nitrogen fertilizer