Although it is well known that groundwater significantly influences plant communities, there have been few studies on how the soil and plant communities respond to groundwater level decline in a short time affected by coal mining. This paper examined the changes in groundwater depth before and after coal mining and the soil-vegetation response in a typical semi-arid grassland coal mine area of Hulunbuir Steppe, Northeastern China. The IsoSource model, based on the dual stable isotopes of δ D and δ 18O, was employed to estimate groundwater contributions to shallow soil (0-100cm) water under different groundwater depths. The results revealed that groundwater was the dominant water source (75.7±17.1%) for shallow soil water when the groundwater depth is less than 4 meters, indicating that 4m is a threshold in groundwater depth, separating groundwater-dependent, and precipitation-driven vegetation system in the study area. Secondly, a strong non-linear response between vegetation species, height, coverage, and groundwater decline was identified in the coal mine area. The vegetation properties were found to be lowest in the areas where groundwater depth increased from 1.5~4 m to 4~28 m before and after coal mining. Finally, the groundwater level decline in the mining area significantly influenced the groundwater-dependent vegetation ecosystem, with the soil CEC and organic matter reduced, and the plant community degraded, succeeding from mesophytic to xerophytic. Whereas, the soil-vegetation system in the non-groundwater-dependent area has no obvious response to the groundwater decline. These results suggest that caution should be exercised when mining in groundwater-dependent ecosystem regions.

Ski tourism’s popularity is driving a rise in the number of ski resorts. This study aims to present the impact of ski infrastructure on soil erosion processes on the example from a small catchment in the Gubałowskie Foothills in southern Poland, where landscape changes before (since 1879) and after the construction of the ski station (2007) were presented. The analyses of changes in flow accumulation, slope morphometry, and drainage ditches were conducted in the test area. Quantitative analyses were performed using repeated DEMs derived from LiDAR survey and detailed geodetic measurements, complemented by geomorphological mapping done in the field. The study has revealed that the ski infrastructure has not only directly transformed the hillslope by flattening and constructing escarpments (up to 3 m high) but has also created alternating patterns of erosion and accumulation. In the test area, the drainage ditch was poorly designed. It was filled by materials (0.1–0.5 m), and two new outlets formed. The escarpment of the analyzed ski run has been diminished by 0.5 m. An alluvial fan (0.1 to 0.22 m thick) has developed on the flattened surface below the escarpment with drainage ditch outlets. This fan is eroded by subsurface flow that creates a piping system. The gully below the alluvial fan has retreated upslope, accelerated by subsurface erosion. This study enables the presentation of hillslope adjustments and processes in response to the new conditions caused by ski infrastructure. Such results may support more effective land management in regions changed by ski infrastructure.