The response of the rotifer community in Loch Leven, UK, to changes associated with a 60% reduction in phosphorus inputs from the catchment

Lakes across the world are suffering from anthropogenically induced nutrient enrichment problems and many attempts are being made to improve their water quality and ecosystem function. Most metrics that are being used to monitor recovery are based on relationships that have been established across a range of lakes. These may not respond quickly to in-lake changes in water quality when nutrient management strategies are put in place. This paper uses data routinely collected from Loch Leven, UK, to examine the immediate and longerterm responses of the rotifer community to a 60% reduction in phosphorus input from the catchment in the early 1990s. We conclude that changes in rotifer abundance and relative species composition are sensitive indicators of lake-specific changes in water quality, responding more quickly than more widely used metrics, such as total phosphorus and chlorophyll a concentrations. However, like all indicators of change, such indices must be used with care in situations where rotifer populations are subject to multiple stressors.