Data from: Recovery of a mining-damaged stream ecosystem

This paper presents a 30+ year record of changes in benthic
macroinvertebrate communities and fish populations associated with
improving water quality in mining-influenced streams. Panther Creek, a
tributary to the Salmon River in central Idaho, USA suffered intensive
damage from mining and milling operations at the Blackbird Mine that
released copper (Cu), arsenic (As), and cobalt (Co) into tributaries. From
the 1960s through the 1980s, no fish and few aquatic invertebrates could
be found in 40 km of mine-affected reaches of Panther Creek downstream of
the metals contaminated tributaries, Blackbird and Big Deer Creeks.
Efforts to restore water quality began in 1995, and by 2002 Cu levels had
been reduced by about 90%, with incremental declines since. Rainbow Trout
(Oncorhynchus mykiss) were early colonizers, quickly expanding their range
as areas became habitable when Cu concentrations dropped below about 3X
the U.S. Environmental Protection Agency’s biotic ligand model (BLM) based
chronic aquatic life criterion. Anadromous Chinook Salmon (O. tshawytscha)
and steelhead (O. mykiss) have also reoccupied Panther Creek. Full
recovery of salmonid populations occurred within about 12-years after the
onset of restoration efforts and about 4-years after the Cu chronic
criteria had mostly been met, with recovery interpreted as similarity in
densities, biomass, year class strength, and condition factors between
reference sites and mining-influenced sites. Shorthead Sculpin (Cottus
confusus) were slower than salmonids to disperse and colonize. While
benthic macroinvertebrate biomass has increased, species richness has
plateaued at about 70 to 90% of reference despite the Cu criterion having
been met for several years. Different invertebrate taxa had distinctly
different recovery trajectories. Among the slowest taxa to recover were
Ephemerella, Cinygmula and Rhithrogena mayflies, Enchytraeidae
oligochaetes, and Heterlimnius aquatic beetles. Potential reasons for the
failure of some invertebrate taxa to recover include competition, and high
sensitivity to Co and Cu.