The littoral benthon community of Lake Orta after liming: a comparison between summer 1993 and summer 1998

At different times in recent years (before, during and after liming) we have studied the littoral macrobenthonic community in Lake Orta, and, for comparison, in Lake Mergozzo (an unpolluted lake). In this paper we compare the situations after liming in summer 1993 and in summer 1998. We found no clear difference between the summer samples in 1993 and 1998 for each site; only seasonal fluctuations were in evidence, in particular in the sites of Gozzano and Pella and in Lake Mergozzo. The two lakes, however, still present marked differences in the composition of their macrobentonic communities.