Combining palaeolimnological and limnological approaches in assessing lake ecosystem response to nutrient reduction

1. Palaeolimnological data and limnological time-series data are highly complementary. Sediment records extend time-scales, integrate subannual variability and expand the range of sites that can be studied, but they suffer from taphonomic biases and occasionally from uncertain chronology. Observational time-series data, on the other hand, are highly resolved but are very limited in extent both in space and time. 2. Palaeolimnological and observational data-sets need to be combined in oligotrophication research to establish (i) the past and present status of lakes needed to identify reference conditions; (ii) changes in ecosystem state; (iii) responses to nutrient reduction; and (iv) the potential role of other factors (e.g. additional stressors, climate change) that might confound predictions of future state.