Traditional ideas concerning environmental management tend to be based
upon simple relationships between cause and effect. Such approaches
make the design of environmental management strategies fairly
straightforward: once the cause of a problem has been identified, it is
necessary only to address the cause and/or help the system to recover
through some sort of attempt at restoration. In the case of shallow
lake eutrophication, research in the 1960s and 1970s identified
phosphorus as the key control on the trophic state of a lake and,
hence, recommended reductions in the supply of phosphorus to lakes as
the necessary remedial measure. However, subsequent research has
illustrated that such measures were not always successful. This article
reviews the science of shallow lake eutrophication to demonstrate the
role of ecosystem-specific biological and chemical interactions in
conditioning the response of lakes to remedial measures and, hence,
shows how new ideas of complexity help us to understand the behaviour
of lake ecosystems so that we can develop alternative environmental
management strategies.