The population decline of Gyps vultures in India and Nepal has slowed since veterinary use of diclofenac was banned

PLoS One. 2012;7(11):e49118. doi: 10.1371/journal.pone.0049118. Epub 2012 Nov 7.

Abstract

Populations of oriental white-backed vulture (Gyps bengalensis), long-billed vulture (Gyps indicus) and slender-billed vulture (Gyps tenuirostris) crashed during the mid-1990s throughout the Indian subcontinent. Surveys in India, initially conducted in 1991-1993 and repeated in 2000, 2002, 2003 and 2007, revealed that the population of Gyps bengalensis had fallen by 2007 to 0.1% of its numbers in the early 1990s, with the population of Gyps indicus and G. tenuirostris combined having fallen to 3.2% of its earlier level. A survey of G. bengalensis in western Nepal indicated that the size of the population in 2009 was 25% of that in 2002. In this paper, repeat surveys conducted in 2011 were analysed to estimate recent population trends. Populations of all three species of vulture remained at a low level, but the decline had slowed and may even have reversed for G. bengalensis, both in India and Nepal. However, estimates of the most recent population trends are imprecise, so it is possible that declines may be continuing, though at a significantly slower rate. The degree to which the decline of G. bengalensis in India has slowed is consistent with the expected effects on population trend of a measured change in the level of contamination of ungulate carcasses with the drug diclofenac, which is toxic to vultures, following a ban on its veterinary use in 2006. The most recent available information indicates that the elimination of diclofenac from the vultures' food supply is incomplete, so further efforts are required to fully implement the ban.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Conservation of Natural Resources
  • Diclofenac / adverse effects*
  • Falconiformes* / genetics
  • Falconiformes* / physiology
  • Food Supply
  • India
  • Nepal
  • Population Dynamics*

Substances

  • Diclofenac

Grants and funding

This project was funded by the Darwin Initiative of the United Kingdom government (http://darwin.defra.gov.uk/) and the Royal Society for the Protection of Birds (RSPB) (http://www.rspb.org.uk). RC and REG are authors of the paper and members of the research staff of the Conservation Science Department of RSPB. Beyond this, the funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.