A coal mine about 2.2 km upstream from Stillfork Swamp Nature Preserve, Carroll Co., Ohio was suspected of causing a reduction in Limnephilus indivisus caddisflies in the south half of the preserve. Second instar L. indivisus larvae collected from the south half of the preserve and from two control areas were reared in cages at the site of collection and at the other two sites in a replicated experiment. Elevated total dissolved solids in water samples from within rearing enclosures displayed strong correlation (r2 = 0.864) with increased mortality when compared to larvae reared in unaffected areas. This investigation suggests that larvae of L. indivisus are useful in biomonitoring of wetlands impacted by acid-mine drainage, and potentially other perturbations
