What killed more than half the world’s saiga antelopes?

In 2015, approximately 220,000 saiga antelopes were found dead in central Kazakhstan in a matter of three weeks. The majority of the critically endangered antelopes found deceased were newborns and mothers who had gathered to calve.

Overall, there was a loss of around 62 percent of the global population of saiga antelopes. In a study published in Science Advances, researchers have used a multidisciplinary approach to investigate what caused this mass mortality event.

According to the study authors, the proximate cause of death is hemorrhagic septicemia, which is a severe bacterial disease caused by some strains of Pasteurella multicoda. Hemorrhagic septicemia leads to blood poisoning and intestinal bleeding. The researchers say that the onset of the disease was likely triggered by abnormally warm and wet weather.

The study authors wrote: “Statistical modeling suggests that there was unusually high relative humidity and temperature in the days leading up to the mortality event; temperature and humidity anomalies were also observed in two previous similar events in the same region.”

Study co-author Richard Kock is a professor at the Royal Veterinary College in London. He explained that climate change may be to blame for this event. With global temperatures continuing to rise, Kock said that another bacterial outbreak is very likely.

“There’s theoretically a possibility of extinction of the species entirely,” said Kock. “We have at least got a number of populations – albeit small ones – that are outside the danger zone.”

Based on the results of their study, the researchers have made recommendations for the future management of saiga antelopes.

“Given the saiga population’s vulnerability to mass mortality and the likely exacerbation of climate-related and environmental stressors in the future, management of risks to population viability such as poaching and viral livestock disease is urgently needed, as well as robust ongoing veterinary surveillance,” wrote the study authors.

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By Chrissy Sexton, Earth.com Staff Writer