Effects of Burmese python predation on Hainan Eld’s deer population

In recent years, Hainan Eld’s deer (Cervus eldi) population in the Datian Nature Reserve (DNR) has been decreasing. This may be due to predation by Burmese python (Python bivittatus), as the number of Eld’s deer predation events by Burmese pythons has increased since 2013. This poses huge pressure on the DNR that is mainly involved in the conservation of wild Eld’s deer population. We divided the changes in deer population size in the DNR into three time periods (1988–1992, 1999–2003, and 2015–2019) according to changes in the number of Burmese pythons. We analyzed changes of Eld’s deer population in the Wenchang conservation station (WNR) for the period 2010–2018. In the DNR, Eld’s deer population increased from 242 to 349 during 1988–1992 in the absence of Burmese python. When there were few Burmese pythons in the region in 1999–2003, Eld’s deer population increased from 702 to 1075. In 2015–2019, when the number of migrating Burmese pythons captured was the greatest, Eld’s deer population decreased from 306 to 223, and the mean annual growth rate was − 6.21%. As predation by Burmese pythons decreases the survival rate of Eld’s deer fawns in the DNR, the growth rate of Eld’s deer population was significantly affected. Our results indicated that predation by Burmese python is currently a key factor affecting the growth of Eld’s deer population.