Development of a new Diatom-Based Index (BDIAR) for biomonitoring Mediterranean streams using data from Algerian Rivers

For the first time, we propose a diatom-based biomonitoring index (BDIAR) for Algerian Rivers. BDIAR is based on water conductivity and diatom autecological profiles. Our study was conducted along the Coastal Central Constantine watershed, from which 78 samples of diatoms and water were collected. Weighted averaging method was used to determine the diatom autecological parameters (optimum and tolerance), estimated for157 diatom species for the first time in our country. There was a significant positive correlation between measured and expected conductivity values of sampling sites based on their diatom composition (r² = 0.64, P = 0.0001). Linear regression statistics revealed a strong correlation between BDIAR and conductivity (Pearson correlation P = 0.0001). Two similar methods (the Index for Soda Pans DISP and Carayon Index) albeit useful for inferring conductivity values were less accurate (P = 0.08 and 0.03 respectively). χ² and κ statistics demonstrated that using our metric yields a correct site classification in water conductivity classes. The BDIAR is not limited to Algerian streams; it can be applied in biomonitoring programs for all freshwater systems with similar ecological conditions after the reference status determined. This adaptability enhances its potential for widespread use in monitoring and managing water quality across various regions.