Relationship between environmental factors and the spatial distribution of Spermophilus dauricus during 2000-2015 in China.

The Spermophilus dauricus is a rodent species that feeds on the tender parts of plants and seeds. It is also a natural carrier of the hepatitis B virus and the main host of the plague bacillus Yersinia pestis threatening human health and the cultivated ecosystems. Based on ecological niche modeling (ENM) for the MaxEnt model and ArcGIS for the Spatial Analyst model, we quantified the potential risk zone and spatial pattern of the S. dauricus outbreak during 2000-2015. We analyze the temporal and spatial variation for different levels of risk zones. The results showed that the S. dauricus was primarily distributed in the North China with arid and semi-arid regions. The suitable habitat of S. dauricus includes an annual precipitation of 250-700 mm year-1, a temperature of - 3 to 14 °C, the normalized differential vegetation index (NDVI) of 0.05-0.65, and an elevation of < 3800 m. Although the NDVI and precipitation were significantly increasing, the potential risk zone did not expand. But, this result can not mean the S. dauricus outbreak had been controlled, and the substantial additional efforts in the form of observational and/or experimental investigations are needed to explore the relationships between environmental factors and the habitat of the S. dauricus, ideally by including the influences from land cover, vegetation characteristics, and artificial disturbances.