Changes in the pelagic communities of Lago Maggiore (Italy) during 1983–1995, when the lake underwent a process of oligotrophication caused by a gradual phosphorus abatement, were analyzed. Events in the plankton after a large increase of Bythotrephes longimunus starting in 1988 were strikingly similar to those in Lake Michigan after the initial Bythotrephes cederstroemii invasion. They included a decrease in numbers of Daphni...