The catchment of the Modrý Potok stream belongs to the network of 14 small catchments (GEOMON), where effects of the changing environment (acidification, eutrophication, global change) on catchment biogeochemistry are studied. The catchment represents unique alpine ecosystem (alpine meadows with limited forest cover). Similarly to the rest of the Czech Republic, a marked decrease in acid deposition has been observed since the 1980s. The measured precipitation chemistry revealed the decrease in sulphur deposition by 80% and moderate decrease in nitrogen deposition (by 50%) since 1994. The decline in acid deposition was caused by reductions of SO2, NOx, and NH3 emissions from heavy industry and thermal power plants (desulphurization). Mountain ecosystem responses to these changes in precipitation acidity were immediate – among other parameters, stream water pH as well as acid neutralizing capacity have increased since 1994. Concurrently, nitrogen retention within the catchment has increased (see the plot below) suggesting that recovery of soil environment has started. These profound changes might have further positive impacts on terrestrial biodiversity.