Dippers are indicators of clean, fast-flowing streams — acidification from forestry and air pollution reduces invertebrate food availability, causing poor breeding success and nutritional stress.
Dipper welfare depends on stream invertebrate abundance. Acidified streams produce fewer caddisfly larvae, stoneflies, and freshwater shrimps — the primary food items. In poor-quality streams, dippers range further, burn more energy, and provision chicks with lower-quality food. Chick survival rates fall in acidified catchments. Liming of acidified streams is a direct welfare intervention proven to restore invertebrate communities within months.