Large experimental fully hydrologically isolated catchment as a tool to study hydrological and ecological processes on multiple scales

Understanding how small-scale processes interact to shape ecosystem development at landscape scales remains a major challenge in environmental science, particularly in post-mining environments where belowground processes are difficult to measure and manipulate. To address this, we established FALCON (2019), an array of four hydrologically isolated artificial catchments (0.25 ha each) in a post-coal mining area in Czechia, enabling controlled, landscape-scale experimentation. Two catchments were reclaimed by leveling and planting alder, while two were left to spontaneous succession on wave-like microtopography. Each catchment is fully instrumented to monitor water, nutrient, gas, and energy fluxes, and includes lysimeters to link small-scale processes to catchment-scale responses. Early studies demonstrate that erosion and deposition strongly control microhabitat formation, with wave-like topography generating pronounced heterogeneity in soil texture, hydrology, and water retention  while homogenization prevail in flat catchments. These processes support surface run off in reclaimed and subsurface run off in unreclaimed catchments. Carbon flux measurements show rapid ecosystem recovery at both reclaimed and unreclaimed sites, with all catchments transitioning from CO₂ sources to sinks within four years; differences between treatments shifted from being driven by soil physical properties to vegetation productivity as alder established. Lysimeter-based assessments indicate that surface water fluxes and evapotranspiration can be reasonably upscaled, particularly in unreclaimed sites, but subsurface flow and solute transport remain poorly represented. Overall, FALCON provides a unique platform to experimentally link erosion, hydrology, biogeochemistry, and carbon exchange across scales