Assessing mining impacts : The influence of background geochemical conditions on diatom and macroinvertebrate communities in subarctic streams

• Published in: Journal of Environmental Management
• Main Authors: Mykrä, Heikki, Kuoppala, Minna, Nykänen, Vesa, Tolonen, Katri, Turunen, Jarno, Vilmi, Annika, Karjalainen, Satu Maaria
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2021
• Subjects: bioassessment; biodiversity; community composition; mineral deposits; reference condition; rivers; mining industry; subarctic region; minerals; Finland; arviointi; biodiversiteetti; biologiset menetelmät; eliöyhteisöt; joet; kaivostoiminta; koostumus; levät; mineraalit; piilevät; päästöt; selkärangattomat; subarktinen alue; vesikemia; virtavedet; Suomi; Ekologia; Evoluutiobiologia; Geotieteet; Ympäristötiede; Fennoscandia; Subarctic; Lapland
• Online Access: http://hdl.handle.net/10138/337070; https://doi.org/10.1016/j.jenvman.2020.111532

Highlights • Mineral deposits influence water chemistry and composition of benthic communities. • Catchments with high potential for minerals and mining have unique stream communities. • Atypical background geology should be integrated in bioassessment of mining. Mining has changed landscapes locally in northern Fennoscandia and there is an increasing pressure for exploitation of the remaining mineral deposits of the region. Mineral deposits, even if unmined, can strongly influence stream water chemistry, stream biological communities and the ability of organisms to tolerate stressors. Using data sampled from six mining areas with three active (gold and chrome), two closed (gold) and one planned mine (phosphate), we examined how mineral deposits and mining influence water chemistry and diatom and macroinvertebrate communities in subarctic streams in Finnish Lapland. We supplemented the data by additional samples compiled from databases and further assessed how variation in background geological conditions influences bioassessments of the impacts arising from mining. We found that water specific conductivity was elevated in our study streams draining through catchments with a high mineral potential. Mining effects were mainly seen as increased concentration of nitrogen. Influence of mineral deposits was detected in composition of diatom and macroinvertebrate communities, but communities in streams in areas with a high mineral potential were as diverse as those in streams in areas with a low mineral potential. Mining impacts were better detected for diatoms using a reference condition based on sites with a high than low mineral potential, while for macroinvertebrates, the responses were generally less evident, likely because of only minor effects of mining on water chemistry. Community composition and frequencies of occurrence of macroinvertebrate taxa were, however, highly similar between mine-influenced streams and reference streams with a high potential for minerals indicating that the communities are ...