Here are 10 indicator species used to monitor pollution and ecosystem health along with what each species indicates: 1. Mayflies - Abundance. Indicates good water quality as they are sensitive to pollution. Their absence suggests pollution. 2. Caddisflies - Presence/absence. Sensitive to pollution and organic waste. Their absence suggests pollution. 3. Stoneflies - Presence/absence. Sensitive to pollution. Their absence suggests pollution. 4. Dragonflies and damselflies - Abundance. Require clean water to breed. Reduced numbers suggest pollution. 5. Amphipods - Presence/absence. Sensitive to low dissolved oxygen which can be caused by pollution