East Africa’s ‘soda lakes’ are rising, threatening their iconic flamingos

Large pink flocks of hundreds of thousands of flamingos—flamboyances of flamingos—are certainly one of nature’s nice spectacles. However colleagues and I’ve uncovered worrying tendencies within the salty and highly-alkaline “soda lakes” of east Africa the place most of those birds stay.

Lesser flamingos are essentially the most quite a few of the six species of flamingo discovered internationally, and greater than three quarters are discovered within the soda lakes of Kenya, Tanzania and Ethiopia. Regardless of their numbers, with estimates ranging between 2 million and three million birds, the species is in decline and formally categorized as “close to threatened.”

The causes of the inhabitants decline have been troublesome to establish as a result of remoteness of many soda lakes and the nomadic nature of the birds. They usually fly at evening between the soda lakes in the hunt for new feeding websites, in response to the growth and bust nature of the cyanobacteria they feed on, generally generally known as blue-green algae.

Nevertheless, rising water ranges at lots of the feeding lakes are decimating the cyanobacteria the birds have developed to eat. In analysis now printed within the journal Present Biology, my colleagues and I discovered that solely half of the lakes that supplied high-quality feeding habitat in 2000 have been nonetheless appropriate feeding lakes in 2022.

Lesser flamingos feed by turning their heads the other way up, pumping water by tremendous hair-like constructions known as lamellae of their beaks and catching solely cyanobacteria of a sure dimension. This extremely specialised tactic means the birds are closely depending on sure cyanobacteria species reminiscent of spirulina.

This is similar vitamin-rich spirulina you may need seen in smoothies or dietary supplements. In nature, the species that flamingos feed on solely grows in extremely salty and alkine circumstances, and in soda lakes it grows in such numbers that these lakes are among the most efficient ecosystems on the planet.

However these lakes are particularly delicate to alter as a result of they usually haven’t any outflowing rivers. And as their waters rise they’re diluted, lowering their salinity and alkalinity and limiting the expansion of the cyanobacteria the flamingos rely on.

Extra water, much less meals

To evaluate the threats going through lesser flamingos, we used satellites to watch 22 key feeding lakes throughout Ethiopia, Kenya and Tanzania between 1999 and 2022. That is the primary time the entire east African vary of lesser flamingos has been monitored at this scale.

Water ranges have risen essentially the most lately in Kenya and Tanzania, significantly at traditionally vital flamingo lakes Bogoria and Nakuru, which supported greater than 1 million birds within the current previous.

Nevertheless Nakuru nearly doubled in dimension between 2009 and 2022, whereas its imply focus of chlorophyll a—a photosynthetic pigment measured by satellites that can be utilized as an estimate of cyanobacteria presence—halved. The variety of birds has noticeably declined in response to the losses of their meals supply.

Lake Natron in Tanzania can also be price highlighting as it’s the solely common breeding web site for lesser flamingos in east Africa. The rising water ranges and declining meals sources at Natron due to this fact threaten not solely present populations however the birds’ capacity to breed within the area, presumably resulting in drastic declines sooner or later.

Rising water ranges are doubtless brought on by a mix of elevated rainfall in current a long time and deforestation which causes the rainfall to run off instantly into the lakes. Rainfall is predicted to extend in east Africa with local weather change, driving additional lake stage rises sooner or later.

It is not fully unhealthy information, for the flamingos a minimum of. Six of the 22 lakes supplied extra appropriate flamingo habitats in 2022 in comparison with 2000. The birds will doubtless discover new feeding lakes in shallow salt pans and seasonal lakes. Nevertheless, with no historical past of flamingos residing there, many of those lakes should not have the identical worldwide protections.

It is not solely the flamingos which are in danger. Soda lakes include crops and animals discovered nowhere else on earth together with fish species, invertebrates and phytoplankton. Declines of their most charismatic birds present an perception into what could possibly be taking place beneath the floor.

These lakes can act as early beacons of how local weather change can impression inland waters internationally. If we need to shield these extremely fragile ecosystems and their iconic pink birds, we’ll need to take motion to mitigate the rising rainfall within the area.

We have to know what’s taking place on the bottom and the place the flamingos are going, so extra common water high quality monitoring and chicken counts are required throughout the soda lakes. We additionally want to guard forests close to the lakes most inclined to alter and restore lake catchments which are already degraded. It will scale back the quantity of rain operating straight into the lakes and can give the cyanobacteria a combating likelihood.

With the appropriate assist, spectacular flamboyances of flamingos will proceed to grace east African lakes sooner or later.

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