Questioning Global Trends in Tiger Populations


Reports claim a dramatic 22% increase in wild-tiger Panthera tigris abundance within 5 years (3,200–3,890 individuals; Associated Press 2016). Such significant population increases could potentially change the status of tigers from endangered to vulnerable on the IUCN Red List, and substantially contribute to the global target of doubling wild-tiger numbers by 2022 (GTRP 2010). While this purported increase has been attributed to improved conservation practices in India, Nepal, Bhutan, and Russia, the claimed increase is questionable given unreported methodology (Russia), lack of comparable baselines (Bhutan and Russia), and failure to adjust population estimates to account for expanded survey effort and methodological changes (Nepal and India). The latter source of bias requires explanation as it accounts for a large portion of the assumed population increase.

Harihar, A., Chanchani, P., Pariwakam, M.,  Noon, B. R, & Goodrich, J. (2017) Defensible Inference: Questioning Global Trends in Tiger Populations. Conservation Letters doi: 10.1111/conl.12406