Ecohydrological processes include interactions within the critical zone, from regolith to atmosphere including living organisms. Our current understanding and model-based prediction of these processes heavily relies on empirical response functions (e.g. those categorised into plant functional types) that have an uncertain transferability in space or time. However, many aspects of these interactions are strongly constrained by physical laws and energetic limits, which are general and hence transferable. Unfortunately, technical limitations reduce our ability to observe key phenomena, such as water mixing and exchange processes. Recent years have seen considerable developments in hydrological and ecological field observation, analyses, and remote sensing methods. They have offered new ‘spectacles’ for observing ecohydrological systems, leading to new insights into their functioning. These include, for example: opportunities for high spatio/temporal resolution monitoring of energy-water cycles, use of tracer techniques, new proxies for ecohydrological processes, and advances in spatial imagery collection and processing. Stable water isotopes are powerful tools for tracing water fluxes and are increasingly applied to better understand processes in the regolith-plant-atmosphere system. While new methods allow measurements on high spatial and temporal scales, studies applying tracer methods are tackling complex interactions within the regolith compartments, ecology, and variable atmospheric drivers.

This session gives an overview of new methodological developments in detecting and understanding ecohydrological processes and their interactions, as well as new progress in understanding their underlying general bio-geo-physico-chemical principles.