This axis aims to analyse and model the response of ecosystems to climate change and extreme events. This axis deals jointly with agricultural and forest ecosystems, and carbon, water and energy transfers. The spatial scales studied range from molecular scale for process analysis to global scale for impact analysis. Themes emerge according to the type of constraint considered:
- Factors that change gradually and continuously over time, such as increases in the average concentration of CO2 in the atmosphere or average temperatures, lead to a gradual response of plant ecosystems. It is therefore necessary to observe these changes, to understand their mechanisms and identify signatures, and to integrate the different compartments of ecosystems (soil-plantatmosphere) in the modelling of functioning.
- Extreme events (such as droughts or storms) lead to ruptures (hydraulic, mechanical, metabolic) with threshold effects. This involves measuring and understanding the effects observed following an event, but also the cumulative effects over time (succession of several droughts or a combination of drought and storm).
- The cross effects between these slow-moving factors and extreme events on ecosystem productivity and functioning. Indeed, some of these factors have antagonistic effects and the final result on biomass production is poorly known. This question opens the field of ecosystem resilience, and on this subject, exchanges with axis 1 and nutrient availability issues are also to be considered.