Research

Climate change increases the frequency and severity of droughts and rainfall events in Austria. The drought-related soil water deficit and the change in rainfall patterns poses a risk for forests, leading to increased tree mortality and loss of ecosystem services. The complex interplay of climate change impacts on trees and the associated response of hydrological components such as precipitation, soil moisture, or runoff is difficult to entangle under temporally-varying, natural conditions. However, detailed knowledge of forest and water interactions are urgently needed in promoting tree-resistance against climate change. Here, we propose controlled manipulation experiments using rain-out shelters and sprinklers to simulate drought and heavy rainfall events in a highly-instrumented, long-term measurement network located in a beech stand of the mountainous Rosalia forest (Lower Austria). We will quantify the percentage of summer and winter precipitation that beech trees transpire, and fluxes of evaporation, transpiration, and groundwater recharge using stable water isotopes. To achieve this, soil and xylem samples will be taken and analysed in the laboratory, and the results of this analysis compared to in-situ high-resolution measurements of soil water and xylem water isotopes using liquid-vapor equilibrium techniques. Further, we will quantify hydrological components using water balance methods and fluorescence tracers. This project will result in estimates of changes in water fluxes under climate change using controlled manipulation experiments as repeated experiments. We will gain insights into forest hydrological changes of Austrian, mountainous beech trees, from which suggestions for forest managers for strategies to promote beech health threatened by increased droughts and heavy rainfalls can be derived.

Digital data and tools are increasingly part of agricultural practice and water management in Austria. Decision support systems can be used to control irrigation digitally and adapted to agrometeorological conditions. Apps and web-based services (e.g., ada.boku.ac.at, eo4water.com) have been developed to facilitate irrigation planning using publicly available satellite, weather, soil, and land use data (e.g., opendatacube.org, data.gv.at). Online probes (e.g., ehyd.gv.at) allow real-time display of groundwater levels or surface water discharges. Water withdrawals for irrigation purposes are recorded with different information density via water information systems (e.g. online water books of the federal states). Some digital tools are already in use, various research projects deal with partial aspects of this topic, data bases are available in different forms at a number of institutions. However, there is a lack of an overview of the current state of research, the available data bases and digital tools, as well as the developments and challenges in this topic area, which would enable targeted further developments and synergetic uses of existing data. Therefore, the current state of research, available data bases and digital tools, as well as current developments and challenges are to be compiled and presented in the form of web-compatible factsheets with the intensive involvement of the relevant stakeholders (agriculture, water management, research). For this purpose, in a first step, the relevant topic areas will be defined in communication with the stakeholders, the research sources will be determined, the criteria for the consideration and evaluation of information will be established, and a standardized form of presentation will be designed. The existing data bases and tools are evaluated for their concrete feasibility, synergy potential, and availability/accessibility for different stakeholders. Complementary to this, identified gaps are presented.

The objectives of this project are 1) to determine the main erosion driving rainfall characteristics and their seasonal varia-bility, 2) to determine occurrence probability of extreme erosion events; and 3) to link precipitation, modeled erosion and damage reports with each other to allow better warnings. Field measurements of rainfall kinetic energy will be combined with soil erosion modelling for agriculturally used areas in Austria to derive range and frequency of erosion inducing rain-fall events and related soil losses. Obtained results will be validated by using damage reports of fire brigade interventions.