Toward a Zimbabwe-specific diatom index: a critical review of global biomonitoring frameworks and their applicability in African freshwater systems

Abstract The use of diatoms in biomonitoring has become an important tool for assessing freshwater health around the world. This is because diatoms provide a quick and cost-effective way to monitor water quality. Thus, creating a diatom-based water quality monitoring index in Zimbabwe would improve freshwater conservation efforts and support biomonitoring strategies that reflect Zimbabwe’s stream ecological situation. The objective of this paper is to elucidate (i) the principles and indices typically employed, (ii) their applicability across different limnological settings, and (iii) potential avenues for creating a diatom index tailored specifically for Zimbabwe. The paper also addresses key challenges like taxonomic gaps, limited infrastructure, and the need for appropriate policy framework in developing and implementing sound diatom-based biomonitoring protocol in the country. This review proposes a mixed framework that blends European biomonitoring standards, like the EU Water Framework Directive, with African-specific methods. This approach ensures that water quality assessments are both ecologically relevant and aligned with policy needs.