Coinciding neatly with World Wetlands Day 2025, ecologists at the Nelson Mandela African Institution for Science and Technology have produced a timely report on some important recent research they conducted. With funding from Live Streams, Dr Grite Nelson Mwaijengo and her colleague Emmanuel Julius carried out surveys of aquatic macroinvertebrates at twelve sites in three river systems in the Lake Manyara Basin. They also carried out habitat assessments and measured water quality. The work was done in freshwater ecosystems where there is limited ecological information in the Afro-tropical region; namely, Intermittent Rivers and Ephemeral Streams (IRES). These watercourses, which periodically stop flowing or dry out, have direct benefits for people are thought to support diverse biological communities.
Dr Mwaijengo and Julius identified a diverse range of macroinvertebrates across the surveyed rivers with variations in species composition influenced by water availability, substrate type, and anthropogenic activities. These included Odonata (dragonflies and damselflies), Hemiptera (true bugs), Coleoptera (beetles), Diptera (flies), Mollusca (snails), Decapoda (freshwater prawns), and Orthoptera (grasshoppers). The macroinvertebrates perform a variety of ecological functions: predating other aquatic organisms; recycling nutrients (detritivores such as chironomid larvae); regulating primary production (for example, snails grazing algae); and enhancing water quality through filter feeding. The findings are being written up in a manuscript for submission to a scientific journal.
A workshop was held in Makuyuni to enhance awareness about IRES, their biodiversity, socio-ecological importance, threats they face, and potential conservation measures. The workshop brought together 33 stakeholders from diverse organizations. It highlighted the need to protect the ecosystems through strengthened community engagement, robust policy frameworks, and further research.
Below: Emmanuel Julius sieving a macroinvertabrate sample. Photo credit: Dr Grite Nelson Mwaijengo