A new study has linked the 2022 Elephant Die-Off in Botswana to toxic algae blooms
The eastern Okavango Panhandle in Botswana’s northeastern region, also known as the Eastern Okavango Panhandle, was discovered to be home to 350 African elephant corpses. The timing of the incident coincided with COVID-19. There were no holistic investigations done as the timing was during the height of COVID-19.
Botswana, home to one-third of African elephants, is a hotspot for poaching. Elephant carcasses that still have their tusks show an alternative cause to poaching. The absence of any clinical evidence ruled out the theory that virulent or bacterial agents were to blame.
A new study by King’s College London researchers provides more evidence of those deaths. In watering holes, toxic blue-green algal blooms or cyanobacteria developed because the previous year had been very wet. Elephants could have been poisoned by drinking from watering holes.
In stagnant, nutrient rich waters, cyanobacteria can be found as planktonic or benthic phototrophic bacteria. Some species that form blooms produce toxins which can be harmful. The blooms have become more common due to climate change and anthropogenic input of nutrients.
“Botswana has a population of African elephants that makes up a third. This unprecedented death rate in their biggest remaining group highlights the growing concern about the Okavango Delta ecosystem, which is one of the planet’s most vital eco-systems.Davide Lomeo.
In southern Africa, cyanobacteria is common and has been previously linked with wildlife deaths. A study published in the Journal Science of the Total Environment confirmed that the toxic algae was the culprit.
King’s College London Image Credit
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In order to study further the relationship between algal blooms, elephants and spatial data, the team used satellite data. Satellite data showed that algal blooms and levels were increasing in 2020.
The data also showed that decayed carcasses of elephants were spread more than those fresh carcasses. The data showed that the elephant death pattern is different from normal.
“The number of waterholes with increased blooms in 2020 was higher than the three previous years. The waterholes in question also had the highest algal biomass average for the years 2015-2023.Davide replied:
Elephants have been estimated to die within 88 hours after drinking water from these holes. The presence of these algal toxins is a serious threat to wildlife.
“Southern Africa will become hotter and drier under climate change, meaning that waterholes in this area are likely to be dry for longer periods of time.Davide Adds.
“The findings of our study point out the negative impact on the quantity and quality of water, as well as the potentially catastrophic consequences for animals.”
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Journal Reference
- Lomeo, D., Tebbs, E. J., Babayani, N. D., Chadwick, M. A., Gondwe, M. J., Jungblut, A. D., McCulloch, G. P., Morgan, E. R., Schillereff, D. N., Simis, S. G., & Songhurst, A. C. (2024). The spatial and remote sensing analysis reveals a cyanobacteria swarm dynamics that is unprecedented. This cyanobacteria swarm has been associated with mass elephant mortality. Science of The Total Environment 957, 177525. DOI: 10.1016/j.scitotenv.2024.177525
