Areal sizes of high, intermediate, low and total suitable habitats are correlated to the global extinction risk for mammals

The relationships between areal sizes of high, intermediate, low, and total sum of habitats with low, intermediate and high suitability habitat ranges, and the International Union for Conservation of Nature (IUCN) threatened status of global terrestrial mammals were studied. Polyserial correlation analysis showed that all types of areal size closely and positively correlated with IUCN categories of threatened species. The results indicate that area-based extinction risk assessment is feasible and reliable in species’ conservation prioritization. Furthermore, the partial polyserial correlation test indicates that significant correlations between the IUCN threatened status of species and range sizes of high, intermediate and low suitability habitats are not influenced by the polyserial correlation between IUCN threatened status and total suitability habitat range size. Thus, the prediction of species’ extinction risks can be accurately fulfilled by evaluating the areal size of any one of total, high, intermediate or low suitability ranges. The present study implies that if the area size information of a totally suitable range is not available for species’ extinction risk assessment, the usage of areal sizes from any parts of suitable habitats (high, intermediate or low) are effective surrogates.