Southern Damselfly Coenagrion mercuriale

This damselfly has extremely picky requirements. It only thrives in pristine, unpolluted springs and cold streams, making it a sensitive bioindicator of water quality. Scientists monitor its presence to track ecosystem health across Europe.

Found from the UK to North Africa, it's increasingly threatened as wetlands dry up and pollution spreads. But wherever cold springs still flow pure, you can spot it hovering gracefully near the water's edge. Its presence is good news—it means the water is clean, cold, and healthy.