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The project examines the impact of hydrogeological factors on lowland forests, with a particular focus on groundwater dynamics, at two selected lowland oak forest sites in Slovenia. These sites, Murska Šuma in the northeast and Krakovski gozd in the southeast, are significant Natura 2000 sites. Under the Water Framework Directive (WFD) and Natura 2000, they are classified as groundwater-dependent ecosystems. Around 20 years ago, physiological decline and a high rate of oak mortality were observed in several lowland oak forests in Slovenia as a result of climate change. This has been evidenced by an increased frequency of extreme weather events, changes in rainfall patterns and amounts, and anthropogenic influences affecting groundwater dynamics. The shallow groundwater level beneath the surface determines the functioning of the forest ecosystem. Trees adapted to these conditions can access water in the saturated zone, which lies just below the surface. During extreme events, such as droughts or seasonal dryness, when the water table falls, trees with deep root systems can still access water. However, if trees are not adapted, extreme fluctuations in groundwater levels can affect the physical characteristics and species composition of forests, and alter relationships within plant communities.

Project Phases and Implementation

DS1: Establish a research scheme to assess the influence of hydrogeological factors on water availability for trees

• DS1.1 Field measurements at two field observatories/piezometers

  • Monitoring of groundwater level, temperature, and electrical conductivity using automatic sensors

  • Monthly water sampling for chemical and isotopic analysis

  • Monthly sampling of wood and soil

  • Geophysical measurements (ground-penetrating radar) to determine the depth of oak tree roots

• DS1.2 Laboratory analyses

  • Isotopic composition analysis of oxygen and hydrogen isotopic composition of water

DS2: Acquiring knowledge on new interdisciplinary methodological approaches

• Preparation of wood and soil samples and data interpretation (research visit at WSL, Switzerland)

• Transfer of new methodological approaches for use in scientific publications and PhD thesis

DS3: Digitising Data

• Collection of publicly available and newly acquired data

• Digitising, statistical processing, and development of hydrogeological conceptual model

• Analytical and numerical modelling of water flow through the unsaturated and saturated zones

• Model validation using tree ecophysiological data and chemical and isotopic water composition

DS4: Disseminating project results

• Publication of at least 2 original scientific articles and 2 conference papers

• Completion of the PhD thesis

• Promotion of interdisciplinary, inter-institutional, and international collaboration