Limnological Responses to Environmental Changes at Inter-annual to Decadal Time-Scales

Abstract

Lake responses to environmental change are complex and occur at a of time-scales. Three case studies are presented and discussed to how numerical and statistical methods can be used to answer critical palaeolimnological questions about lake responses to environmental change at the inter-annual or sub-decadal time-scales. These all involve lakes with annually-laminated sediments. They concern the comparison of annual sediment records with instrumental data to study the effects of nutrients and climate on the Swiss lake of Baldeggersee; the comparison of diatom stratigraphical data and tree-ring based climate at Kassjön, a lake in central-northern Sweden; and the assessment of the effects of volcanic tephra deposition and climatic change on pollen and diatom stratigraphical assemblages at Holzmaar in west-central Germany. These case studies highlight the need for careful definition of the research question or hypothesis to be tested, the selection of ecologically relevant response proxies, the critical choice of predictor variables as proxies for stress and environmental change, and the selection of appropriate numerical and statistical techniques.