Flamingos in danger. Rising alkaline water levels a threat to populations

The image of the numerous flocks of flamingos adorning East Africa’s soda lakes is not only stunning in its beauty, but also symbolizes the region’s rich biodiversity. However, a recent study by researchers at King’s College London reveals disturbing trends in saline and alkaline lakes, putting the future of these beautiful birds in doubt. Due to environmental changes resulting from global warming and human activities, flamingos may soon be in mortal danger.

Soda lakes

Soda lakes, also known as alkaline lakes, are a type of reservoir with high concentrations of sodium bicarbonate and other salts, especially sodium. They are characterized by a very high pH, often exceeding 9 or 10, which means that the water in these lakes is alkaline. They are usually located in arid or semi-arid areas, where evaporation far exceeds water inflow, resulting in mineral accumulation. These unique conditions foster the formation of unique ecosystems populated by specialized organisms, including cyanobacteria and algae. Soda lakes are home to most flamingo populations, mainly in Kenya, Tanzania and Ethiopia.

Soda lakes are important areas with high sensitivity to environmental changes, such as increased rainfall and human activities, which can alter salinity and alkalinity, threatening the species that depend on them. Research published in the journal Current Biology showed that only half of the lakes that in 2000. had environmental quality, retained it until 2022.

Study of soda lakes

Soda lakes in East Africa have experienced significant fluctuations in water levels in recent decades. This phenomenon has prompted scientists to investigate the causes of these changes and their consequences for the ecosystems there, particularly the population of lesser flamingos. The study was carried out using a wide range of tools and techniques, allowing for a detailed analysis and understanding of the complex interactions in the ecosystem of 22 soda lakes that are feeding grounds for flamingos in East Africa. A key element of the study was the use of imagery and satellite data from the last two decades of Earth observation. This allowed us to accurately measure changes in water levels and understand how they affect food availability for flamingos.

The climatic data collected, such as precipitation and temperatures, were analyzed to understand how changing weather conditions shape lake levels. The study also included regular observations of flamingos, which helped determine how the number of birds in each location changes depending on the availability of food and the condition of the lakes. This combination of birdwatching data and satellite analysis provided a more complete picture of the impact of environmental changes on flamingos.

Flamingos vs. changing lakes

Changes in water levels in East Africa’s soda lakes have serious consequences. Growth leads to dilution of chemical components, resulting in lower salinity and pH. This, in turn, negatively affects the growth of the cyanobacterium Arthrospira fusiformis, also known as spirulina. These microorganisms are a key source of food for the flamingos, as well as an important element affecting the health of the entire ecosystem.

Arthrospira fusiformis provides not only essential nutrients, but also pigments that help birds get their characteristic pink feather coloration. A diet based on this cyanobacterium provides all the nutrients needed, and reducing its availability can lead to malnutrition and weakened flamingo populations. Lowering salinity and pH is particularly problematic because Arthrospira fusiformis thrives best in environments with high alkalinity and relatively high salt concentrations. When these conditions are not met, the alga not only stops growing, but can also be displaced by less specialized but more tolerant phytoplankton species, leading to changes in the trophic structure of the entire ecosystem.

Rising water levels – dwindling food resources

In an extensive study, the researchers were able to observe for the first time how the availability of food in the lake network is changing, noting significant declines in recent years and a decrease in the number of birds as water surface area increases. The largest losses in phytoplankton biomass were observed in Kenya’s equatorial lakes, particularly in the popular tourist destinations of Bogoria, Nakuru and Elmenteita, as well as in lakes in northern Tanzania, where the largest increases in reservoir area were recorded.

Lake Nakuru, one of the key flamingo feeding sites in East Africa, has historically hosted more than 1 million of these birds at a time. Between 2009 and 2022, the reservoir’s surface area increased by as much as 91 percent, while the average concentration of chlorophyll, an important indicator of phytoplankton quantity, fell by half.

Researchers have also identified lakes that could become future feeding grounds for the birds. Dr. Emma Tebbs of King’s College London, co-author of the study, stressed that while flamingos naturally migrate in search of food, a serious challenge is the degradation of their traditional foraging and breeding sites. Researchers also warn that the birds may be forced to forage in new, unprotected areas, especially with the predicted increase in precipitation associated with climate change.

In response to these challenges, scientists are calling for international, coordinated conservation efforts, more effective monitoring, and more sustainable management of the lands surrounding the key lakes for flamingos.