Analysis of changes in hydrological cycle of a pristine mountain catchment. 2. Isotopic data, trend and attribution analyses

delta O-18 in precipitation at station Liptovsky Mikulas (about 8.5 km south from the outlet of the Jalovecky Creek catchment) remains constantly higher since 2014 that might be related to greater evaporation in the region of origin of the air masses bringing precipitation to the studied part of central Europe. Increased delta O-18 values are reflected also in the Jalovecky Creek catchment runoff. Seasonality of delta O-18 in the Jalovecky Creek became less pronounced since 2014. The most significant trends found in annual hydrological data series from the catchment in the study period 1989-2018 have the correlation coefficients 0.4 to 0.7. These trends are found in the number of flow reversals (change from increasing to decreasing discharge and vice versa), June low flow, number of simple runoff events in summer months (June to September) and the flashiness index. The attribution analysis suggests that drivers responsible for the changes in these data series include the number of periods with precipitation six and more days long, total precipitation amount in February to June, number of days with precipitation in June to September and total precipitation in May on days with daily totals 10 mm and more, respectively. The coefficients of determination show that linear regressions between the drivers and supposedly changed data series explain only about 31% to 36% of the variability. Most of the change points detected in the time series by the Wild Binary Segmentation method occur in the second and third decades of the study period. Both hydrometric and isotopic data indicate that hydrological cycle in the catchment after 2014 became different than before.