Study shows Africa’s iconic flamingos threatened by rising lake levels

• Rising water levels in East Africa soda lakes are causing a decline in lesser flamingo populations
• The research found rising water levels across the region’s soda lakes were diluting their normally salty and alkaline nature
• Authors of the study warn that the birds are likely to be drawn to new unprotected areas in the search for food which will have implications for conservation

New research led by Natural History Museum and King’s College London scientist, Aidan Byrne, has revealed how the lesser flamingo is in danger of being forced out of its historic feeding grounds in East Africa’s lakes, with serious consequences for the future of the species.

For the first time ever, satellite earth observation data from over two decades has been used to study all of the key flamingo feeding lakes in Ethiopia, Kenya and Tanzania. The data revealed how rising water levels are reducing occurrences of phytoplankton, the birds’ main food source, due to a change in the alkaline and saline nature of the lakes.

The authors warn the birds are likely to be pushed into new unprotected areas in the search for food, especially given the higher levels of rainfall predicted due to climate change, which may impact the iconic huge flocks we’re used to seeing around East Africa’s lakes.

They are now calling for coordinated conservation action across international borders, improved monitoring and more sustainable management of land surrounding important flamingo lakes.

Lead author, Aidan Byrne, a PhD student jointly supervised by the Museum and King’s College London, said the region was home to more than three quarters of the global population of lesser flamingos, but their numbers are declining.

“Lesser flamingos in East Africa are increasingly vulnerable, particularly with increased rainfall predicted for the region under climate change. Without improved lake monitoring and catchment management practices, the highly specialised species found in soda lake ecosystems – including lesser flamingos - could be lost,” commented Aidan.

This analysis combined satellite earth observation data of the 22 key flamingo-feeding soda lakes in East Africa with climate records and bird observation data from across two decades. Researchers were able to spot changing food availability across the whole network of lakes, including significant declines in recent years, and a decrease in bird numbers as lake surface area increased. They also identified the lakes the birds may move to in the future.

Dr Emma Tebbs, from King’s College London and co-author of the study, said, “East African populations could potentially move north or south away from the equator in search of food resources. Whilst six study lakes increased in habitat suitability from 2010 to 2022, only three of those have some level of conservation protection.

“Increases in water levels could lead to lesser flamingos becoming more reliant on lakes that are unprotected, outside of current nature reserves and protected sites, which has implications for conservation and ecotourism revenues.”

Soda lakes are some of the harshest environments on Earth, being both highly saline and very alkaline. Despite this, many species have evolved to thrive in these conditions, including the flamingo and its phytoplankton prey, which they filter from the water using their sieve-like beaks.

The research found rising water levels across the region’s soda lakes were diluting their normally salty and alkaline nature. This was leading to a decline in populations of phytoplankton, which was measured by the amount of a photosynthetic pigment called chlorophyll-a present in the lakes.

The team found that phytoplankton levels have been declining over the 23 years of study and linked this to increases in the surface areas of the lakes over the same period.

The largest losses in phytoplankton biomass occurred in the equatorial Kenyan lakes, notably at the important tourist lakes Bogoria, Nakuru and Elmenteita, and in the northern Tanzanian lakes that concurrently saw the largest increases in surface area.

Nakuru is one of the most important flamingo feeding lakes in East Africa, historically supporting over one million birds at a time. The lake increased in surface area by 91% from 2009 to 2022 whilst its mean levels of chlorophyll-a concentrations halved.

Natron in Tanzania is the only regular breeding site for lesser flamingos in East Africa and it has experienced declining productivity alongside rising water levels in recent years. If phytoplankton biomass continues to decline there and at other nearby feeding lakes, it will no longer be a suitable breeding site.

The study, published in the journal Current Biology, is now available here.

In addition to scientists from King’s College London and the Natural History Museum, the team also included researchers from National Museums of Kenya, the Tanzania Wildlife Research Institute, the Zoological Society of London, the University of Leicester, and the Freshwater Biological Association.

Visitors to the Natural History Museum, London, will soon be able to discover even more about birds at our new exhibition Birds: Brilliant and Bizarre, which will explore all of the weird and wonderful adaptations and behaviours that have made birds the ultimate survivors. The exhibition opens 24 May and tickets are available to book now.

ENDS

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