Rationale

Central to our capability to develop adaptation strategies is a sophisticated knowledge of the responses of landscapes to changing climate on different time scales. In this respect, natural experiments of dramatic changes in the past represent important examples from which we can learn about ecosystem response to climate change. Moreover, a reliable assessment of presently observable surface processes needs to consider the past evolution of landscapes under specific natural and human influences, i.e. the long-term ‘memory’ of landscapes. On the catchment scale material fluxes and re-organization represent the most obvious environmental responses to anthropogenic and climatic forcing that will be instrumentally observed within TERENO from today into the future. The required additional information from the past can be ideally obtained from high-resolution natural archives in the landscape like, for example, lakes and mires which act as continuous sediment traps. It is a major challenge to link information from the past with instrumental data of presently ongoing processes for a mechanistic understanding of crucial landscape processes. Extending modern observational time series into the past will provide a significant contribution to major scientific questions:

1. How rapid can natural climate and environment changes occur and what are the driving factors?
   
   
2. What is the recurrence time of extreme events (floods, droughts, storms, insect calamities) and how are the causal relations to global climate trends?
   
   
3. How did variations in global climate affect regional moisture availability related and what were the amplitudes of change?
   
   
4. How can the thresholds in climate and landscape systems leading to sudden shifts be described ? Are there any prognostic symptoms detectable beforehand such a sudden shift?
   
   
5. To which extent are ecosystems influenced by old structures from the past? What are the consequences for developing successful adaptation strategies?
   
   
6. How did human societies cope with climate changes? What were their adaptation strategies and what were the consequences for subsequent landscape developments?