Enormous pink flocks of thousands and thousands of flamingos – flamboyances of flamingos – are one in every 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 the world over, and greater than three quarters are discovered within the soda lakes of Kenya, Tanzania and Ethiopia. Regardless of their numbers, with estimates ranging between two million and three million birds, the species is in decline and formally categorised as “close to threatened”.
The causes of the inhabitants decline have been troublesome to determine because of the remoteness of many soda lakes and the nomadic nature of the birds. They usually fly at evening between the soda lakes looking for new feeding websites, in response to the increase 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 advanced 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 had been nonetheless appropriate feeding lakes in 2022.
Lesser flamingos feed by turning their heads the wrong way up, pumping water by means of wonderful hair-like buildings referred to 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 identical vitamin-rich spirulina you might need seen in smoothies or dietary supplements. In nature, the species that flamingos feed on solely grows in extremely salty and alkine situations, and in soda lakes it grows in such numbers that these lakes are a few of the best ecosystems on the planet.
However these lakes are particularly delicate to vary 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 dealing with lesser flamingos, we used satellites to observe 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 in recent times in Kenya and Tanzania, notably at traditionally necessary flamingo lakes Bogoria and Nakuru, which supported greater than 1 million birds within the latest previous.
Nevertheless Nakuru virtually 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 be price highlighting as it’s the solely common breeding website for lesser flamingos in east Africa. The rising water ranges and declining meals sources at Natron subsequently threaten not solely present populations however the birds’ capacity to breed within the area, probably resulting in drastic declines sooner or later.
Rising water ranges are doubtless brought on by a mix of elevated rainfall in latest many years and deforestation which causes the rainfall to run off instantly into the lakes. Rainfall is predicted to improve in east Africa with local weather change, driving additional lake stage rises sooner or later.
It’s not completely dangerous information, for the flamingos at the very least. 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, and not using a historical past of flamingos residing there, many of those lakes don’t have the identical worldwide protections.
It’s not solely the flamingos which are in danger. Soda lakes comprise 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 occurring beneath the floor.
These lakes can act as early beacons of how local weather change can affect inland waters the world over. If we need to defend these extremely fragile ecosystems and their iconic pink birds, we’ll should take motion to mitigate the growing rainfall within the area.
We have to know what’s occurring on the bottom and the place the flamingos are going, so extra common water high quality monitoring and fowl counts are required throughout the soda lakes. We additionally want to guard forests close to the lakes most inclined to vary and restore lake catchments which are already degraded. This may scale back the quantity of rain operating straight into the lakes and can give the cyanobacteria a combating probability.
With the precise assist, spectacular flamboyances of flamingos will proceed to grace east African lakes sooner or later.
Aidan Byrne PhD Candidate, Division of Geography, King’s School London.
This text was first printed on The Dialog.