The impact of a small hydropower plant (SHP) on benthic algae, macroinvertebrate community and ichthyofauna of the Panjica River (Serbia)

The impact of a small hydropower plant (SHP) on aquatic communities (benthic algae, macroinvertebrates and ichthyofauna) and water quality was investigated in the Panjica River (Serbia). The field research was conducted at three localities in November 2024. The results showed differences in community composition between localities upstream and downstream of the SHP, with the greatest impact observed immediately downstream of the water intake. A decline in benthic diatom and macroinvertebrate diversity was observed. Non-diatom algae more clearly indicated the changes in habitat conditions caused by the SHP's operation, as evidenced by the excessive growth of the cyanobacterium Microcoleus autumnalis. The greatest impact was observed in the ichthyofauna, which was absent at the site immediately downstream of the SHP. The ecological status assessment based on diatoms showed no differences, while the macroinvertebrates indicated a deterioration in water quality downstream of the SHP. Long-term monitoring is recommended to better assess SHP's impact.