Abstract: Changes in the distribution of organisms throughout different geological times have been widely investigated by niche modeling. This knowledge is of great importance for biodiversity conservation in front of anthropogenic global warming. Pseudotaxus chienii (Cheng) Cheng is an endangered plant species scattered in southeast China. In this study, we reestablished its distribution ranges in five periods (Last Interglacial, LIG; Last Glacial Maximum, LGM; MidHolocene, MH; current and future) using 34 presence records by niche modeling based on 19 bioclimatic factors. The results showed that precipitation of driest month was the key bioclimatic factor affecting its distribution, suggesting that this species prefers a humid climate with a short dry season. During the LIG, P. chienii distributed widely in southeastern China. During the LGM, the distribution area of P. chienii expanded to Zhejiang, Fujian, the east of Guizhou, and the optimal distribution in the central China (Jiangxi and Hunan) decreased. During the MH, the optimal distribution area was decreased than that in the LGM, with more serious habitat fragmentation than that in LIG. In the future, the suitable distribution area of P. chienii will decrease under the predicted warming climate. The species will shrink to the higher elevations, and the suitable area of middle and low altitude (below 600 m) will disappear largely. Our results present an important insight into the response of P. chienii to climate changes, and provide a guideline for the conservation of this endangered species.

Key words: organic materials, DTPA-Zn, distribution index of Zn, Zn fractionation, mobility factor of Zn