Evidence for responses in water chemistry and macroinvertebrates in a strongly acidified mountain stream
Abstract
A study of differences in the water chemistry and macroinvertebrate composition after a decade was performed in a strongly acidified mountain stream in the Brdy Mountains. In 1999 and again in 2010 we carried out monthly sampling of stream water and macroinvertebrates.
We detected significantly lower concentrations of SO42-, Ca2+, Mg2+, Na+, NH4+, Cl- and F- ions, reactive aluminium (R-Al) and its toxic form Aln+, and significantly higher concentrations of total organic carbon (TOC) between 1999 and 2010, possibly indicating recovery of this stream from acidification, even though there was no significant difference in pH. The signs of a biological recovery from acidification included the first occurrences of less acid-tolerant macroinvertebrate taxa: the stonefly Diura bicaudata and the caddisfly Rhyacophila sp.
We observed higher taxonomic richness in 2010 compared to 1999 and found several species typical of standing waters plus a few rare species. This could partly be attributed to the effects of logging in the catchment.
If recovery from acidification continues, we expect a return of other less acid-tolerant taxa to this strongly acidified stream.