Integrated multi-scale ecohydrogeological monitoring of spatio-temporal dynamics in karst critical zones

• A novel multi-scale ecohydrogeological monitoring approach for KCZ is presented. • Strategic site selection ensures representativeness in heterogeneous karst terrains. • Customized precipitation monitoring and soil solution sampling were developed. • Recommendations for logger placement in fluctuating water level areas were given. • Opportunities to integrate sensor networks and up-scaling are emphasized. Contemporary environmental concerns highlight the vulnerability of karst environments to changing hydrometeorological patterns and vegetation disturbance, necessitating a unified, interdisciplinary strategy for comprehensive understanding. This paper critically examines the current state of research. To overcome the identified gaps, it presents an integrated multi-scale ecohydrogeological monitoring approach tailored to karst critical zones (KCZ) and its spatio-temporal variability. Forested karst aquifer in Slovenia is used as a case study to demonstrate and assess the strengths and limitations of the proposed monitoring framework. To decipher flow dynamics and propose customized data collection strategies the approach combines surface and underground sites and employs advanced methods adapted to the challenges of karst environments. The results highlight the benefits and advancements of monitoring and sampling approaches to ensure representativeness in heterogeneous environments. The focus is on the use of enhanced precipitation monitoring systems to expand sampling areas nearly fivefold and improve precipitation and throughfall measurements. Additionally, customized lysimeter techniques for karst soils and microscale adaptations for cave exploration have been developed, addressing the challenges of instrument placement in environments with significant variability. Further opportunities lie in improving instrument protection, integrating sensor networks, combining remote sensing and scaling from plot to aquifer level. However, challenges remain in achieving spatio-temporal representativeness and ensuring the operational reliability of snow monitoring, soil solution sampling and drip flow measurements. Threats include environmental pressures and hydrometeorological conditions, equipment tampering and funding stability. Nevertheless, this comprehensive approach improves monitoring of ecohydrogeological processes in the KCZ, promotes interdisciplinary collaboration and environmental resource management.