Rate of Decline of the Oriental White-Backed Vulture Population in India Estimated from a Survey of Diclofenac Residues in Carcasses of Ungulates
2007

Decline of the Oriental White-Backed Vulture Population in India Due to Diclofenac

Sample size: 1848 publication 10 minutes Evidence: high

Author Information

Author(s): Green Rhys E., Taggart Mark A., Senacha Kalu Ram, Raghavan Bindu, Pain Deborah J., Jhala Yadvendradev, Cuthbert Richard

Primary Institution: Conservation Science Group, Department of Zoology, University of Cambridge

Hypothesis

The study investigates whether diclofenac residues in ungulate carcasses are sufficient to account for the decline of the oriental white-backed vulture population in India.

Conclusion

The level of diclofenac contamination found in ungulate carcasses was sufficient to account for the observed rapid decline of the oriental white-backed vulture in India.

Supporting Evidence

  • The study found measurable levels of diclofenac in 10% of the liver samples from ungulate carcasses.
  • The estimated death rate per meal for vultures was 2.66% to 3.23% depending on the feeding interval.
  • The observed rate of decline from road transect counts was 48% per year, significantly lower than the expected decline based on diclofenac levels.

Takeaway

Vultures in India are getting sick and dying because they eat animals that were treated with a medicine called diclofenac, which is harmful to them.

Methodology

The study involved surveying diclofenac concentrations in liver samples from carcasses of domesticated ungulates and modeling the impact on vulture population trends.

Potential Biases

There is a risk of bias in the sampling of ungulate carcasses, which may not accurately reflect the exposure of vultures to diclofenac.

Limitations

The precision of the estimate based on carcass surveys is low, and the sampling may not be representative of all carcasses available to vultures.

Participant Demographics

The study focused on domesticated ungulates in India, including various species such as cattle and buffalo.

Statistical Information

P-Value

0.021

Confidence Interval

95% confidence limits for mortality estimates ranged from 34% to 62%.

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1371/journal.pone.0000686

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