Lichens and epiphytes as sentinel organisms for the determination of the water balance in forest ecosystems of South Tyrol

Lichens and fog are one of the primary components of the water balance in the coniferous forest, which affect the hydrological cycle in the ecosystem. This paper investigates the role of fog during mixed rain-fog situations in an old-grown forest with presence of lichens - Evernia divaricata and Pseudevernia furfuracea. Fog represents a form of low-lying cloud and is greatly impacted by geographic setting, wind conditions, and water streams. Using methods of environmental statistics, the effect of forest stand age, fog, and abundance of lichens on the water balance were investigated. The results demonstrated that the presence of lichens and fog are related to humidity and maintains water balance in the forests of South Tyrol. Specifically, the interception was found to play a dominant role in the precipitation and evapotranspiration partitioning, especially in the older stand, where it was enhanced by lichens. Using modelling techniques, this study proved the importance of fog and lichens for the boreal forests ecosystems: fog transfers water from the atmosphere to the terrestrial surface, and lichens plays a significant role in increasing humidity in old stands.