Aquatic Insects Biodiversity and Water Quality Assessment of Ala Stream Located in Roadblock, Akure, Ondo State, Nigeria

Background and Objective: Water quality is a crucial determinant of aquatic ecosystem health, yet it is increasingly threatened by anthropogenic activities. Bioindicators such as aquatic insects provide valuable insights into the ecological integrity of freshwater bodies. This study aimed to assess the water quality of the Ala Stream in Akure, Nigeria, using aquatic insect biodiversity and physicochemical parameters as indicators. The objective was to determine the diversity and abundance of aquatic insects and evaluate their relationship with key physicochemical parameters to infer the ecological health of the stream. Materials and Methods: Sampling was conducted over six months at three designated sites along the stream (upstream, midstream, and downstream). Aquatic insects were collected using a 200 mm mesh dip-net, preserved in 70% ethanol, and identified to the family level using standard taxonomic keys. Physicochemical parameters, including pH, dissolved oxygen, temperature, turbidity, electrical conductivity, and nutrient levels, were analyzed using standard field and laboratory methods. Data were statistically analyzed using ANOVA, Pearson correlation, and diversity indices to determine variations across sites. The p<0.05 indicates the level of significance. Results: A total of 815 aquatic insect individuals from 19 genera and 11 families were recorded, with Chironomidae being the most abundant (36.32%). Diversity indices indicated the lowest taxa richness and diversity at Station 1 (upstream), while Station 3 (downstream) exhibited the highest diversity. Physicochemical analysis revealed variations in water quality across the stations, with some parameters exceeding WHO-recommended limits, indicating potential pollution. Conclusion: The study highlights significant correlations between aquatic insect diversity and specific physicochemical parameters, reinforcing their role as bioindicators. Findings provide critical insights into the ecological health of road block stream, emphasizing the need for integrated biological and physicochemical assessments in freshwater monitoring. This research contributes to sustainable water resource management in Nigeria.