Spatiotemporal heterogeneity of the potential occurrence of Oedaleus decorus asiaticus in Inner Mongolia steppe habitats

Grasshopper plagues have posed a severe threat to grasslands in Inner Mongolia, China. How to predict and control grasshopper infestations has become an urgent issue. We sampled 293 plots in Xianghuangqi County, measured the density of the most dominant grasshopper species, Oedaleus decorus asiaticus, and the latitude, longitude, and certain habitat factors at each plot. We estimated the grasshopper habitat suitability using a fuzzy evaluation model combined with 3S technology, and evaluated the grasshopper climatic suitability during the period 2001-2010. The integrated suitability ranks can indicate the corresponding ranks of potential occurrence of grasshoppers (POG) well. The spatial pattern of POG was closely associated with that of habitat suitability. O. decorus asiaticus was most likely to be found at flat sites or southern/eastern slopes with elevations of 1300-1400 m, typical chestnut soil with sand content of 60-80% in the topsoil, and medium vegetation coverage of 30-50% on temperate bunchgrass steppe. The annual variations in spatial pattern of POG were mainly due to variations in climatic suitability. Spring drought and spring high temperature might cause grasshopper plagues. This study provides an effective means for predicting the locations where grasshoppers might occur using relatively stable habitat factors and a few climatic factors.