Plant Functional Traits and Soil Properties of Machine-Graded Ski Runs over Mid and Long-Term Site Management

The construction of high elevation ski slopes has a long-term impact on the local and neighbouring environment. During the construction of machine-graded slopes the entire vegetation cover and topsoil are removed and replaced with a highly modified top layer comprising of a mixture of coarse materials from lower layers and fine materials from the upper soil horizon. This results in significant changes to the physical, chemical and biological soil properties, extending the time needed for successful site restoration. The establishment and development of plant communities affects both the biotic and abiotic soil environment and the entire alpine ecosystem.The aim of the study, is to evaluate the changes in plant-soil properties of machine-graded ski slopes under mid and long-term site management by comparing the outcomes to undisturbed sites. Four machine-graded ski slopes at 2200-2600 m a.s.l., subject to different periods of management (4-25 years) were surveyed under the framework of the Interreg Alpine Space project, Links4Soils (ASP399). Data collection was carried out on an extensive number of soil and plant properties including relevant root traits i.e. rooting depth, total root length, root diameter, root density, root length density and root biomass. Visual estimation of soil erosion was also quantified to evaluate the soil stabilization potential of the restored sites. Low vegetation cover (17%) with low number of species (9) were found at higher elevations whereas the most species-rich ski runs (43) with high cover (92%) were found at lower elevations independently of the age of management. Root trait results were site specific and showed great differences between the mid and long-term site management as well as between the control and the ski runs. Soil properties on the ski slopes showed an increased level of compaction and pH, lower level of aggregate stability and organic matter content compared to the control.