The influence of physical–chemical variables on phytoplankton and lesser flamingo (Phoeniconaiasminor) abundances in Lake Natron, Tanzania

Abstract

AbstractSoda lakes are alkaline ecosystems characterised by extreme conditions and are one of the most productive aquatic ecosystems. Lesser flamingo, an obligate phytoplankton filter feeder, is widely identified as the flagship species of these saline‐alkaline wetlands throughout the African continent. This study, carried out at three lagoons in Lake Natron for ten consecutive months from March 2019, investigated the relationship between Chlorophyll‐a and lesser flamingo abundances, and physical–chemical variables and Chlorophyll‐a abundance. Lake Natron is the only regular breeding site for the East African population of this specialised species and is known to host thousands of birds year‐round. There was a strong correlation between lesser flamingo and Chlorophyll‐a abundances. Chlorophyll‐a abundance was significantly influenced by dissolved oxygen, water turbidity, phosphate, nitrate and ammonium. Findings from this study suggest that annual fluctuation in the lesser flamingos numbers in Lake Natron is triggered by phytoplankton abundance whose primary productivity is influenced by physical–chemical variables in the lake waters. In turn, these changes are mainly due to both anthropogenic activities and weather changes within the lake basin and its surroundings. Thus, the conservation and management of this lake require concerted efforts from different stakeholders including those found in Kenya.