Limnological research in the deep southern subalpine lakes: synthesis, directions and perspectives

Retrospective assessment of macrophytic communities in southern Lake Garda (Italy) from in situ and MIVIS (Multispectral Infrared and Visible Imaging Spectrometer) data

“…Therefore, the progressive loss of dense macrophyte stands is coupled with an increase in WLF, which, in turn, is strongly influenced by the steady decrease in the minimum water level (see Figs 2 and 4). We suggest that the water table reductions could enhance the competitive effects of phyto-plankton on submerged vegetation favoring the displacement or the exclusion of phanerogams and charophytes in Lake Garda that could be considered as a trophic changing basin (Salmaso 1996;Salmaso, and Mosello 2010). In fact, over the last 35 years Lake Garda clearly witnessed a worsening of the trophic condition with a significant increase in phosphorous content reaching a concentration peak in 2005 (Salmaso 2010;Salmaso, and Mosello 2010).…”

“…We suggest that the water table reductions could enhance the competitive effects of phyto-plankton on submerged vegetation favoring the displacement or the exclusion of phanerogams and charophytes in Lake Garda that could be considered as a trophic changing basin (Salmaso 1996;Salmaso, and Mosello 2010). In fact, over the last 35 years Lake Garda clearly witnessed a worsening of the trophic condition with a significant increase in phosphorous content reaching a concentration peak in 2005 (Salmaso 2010;Salmaso, and Mosello 2010). Consequently, significant modifications have affected the lake's phytoplankton community thus leading to periodic blooms of filamentous cyanobacteria, especially in the southern portion of the lake (for further information, see Salmaso 2005Salmaso , 2010.…”

“…Despite that, we can highlight the main transformation processes in the diversity and relative abundance of plant species on the basis of data provided by Bianchini et al (1974), Wiegleb (1983, Borsani et al (2000), Ludovisi et al (2004), Bolpagni (2005, unpublished data) and this work. These data allowed for a general diachronic comparison of the hydrophytic contingent in the study area over the last 35 years, namely in the period of the major changes of the trophic status of Lake Garda as highlighted by Salmaso (2005Salmaso ( , 2010 and Salmaso, and Mosello (2010).…”

“…It is characterized by great depths (360 m) and large volumes (49 km 3 ). Lake Garda contains 30% of Italy's whole natural and artificial lake water resources (Salmaso, and Mosello 2010). Lake Garda belongs to a distinct typology of Italian subalpine lakes located on the southern edge of the Alps, with a surface of 368 km2.…”

“…Complete water circulation occurs at irregular intervals in connection with exception-ally cold winters (Salmaso et al 2009). According to recent limnological investigations, the Lake Garda basin presents a stable trend in an oligo-mesotrophic condition (Salmaso, and Mosello 2010).…”