Fulltext

The relationship between plant species richness and soil aggregate stability can depend on disturbance

Pohl, Mandy ; Graf, Frank ; Buttler, Alexandre ; Rixen, Christian

In: Plant and Soil, 2012, vol. 355, no. 1-2, p. 87-102

Add to personal list
    Title
    • The relationship between plant species richness and soil aggregate stability can depend on disturbance
    Author
    • Pohl, Mandy. WSL Institute for Snow and Avalanche Research SLF, Unit Community Ecology, Mountain Ecosystems, Flüelastrasse 11, 7260, Davos Dorf, Switzerland
    • Graf, Frank. WSL Institute for Snow and Avalanche Research SLF, Unit Community Ecology, Mountain Ecosystems, Flüelastrasse 11, 7260, Davos Dorf, Switzerland
    • Buttler, Alexandre. Swiss Federal Institute for Forest, Snow and Landscape Research, Unit Community Ecology, Pasture Woodlands and Wetlands, POB 96, 1015, Lausanne, Switzerland
    • Rixen, Christian. WSL Institute for Snow and Avalanche Research SLF, Unit Community Ecology, Mountain Ecosystems, Flüelastrasse 11, 7260, Davos Dorf, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:315681
    Summary
    Aims: Plant diversity has been shown to significantly increase topsoil aggregate stability of machine-graded ski slopes. We hypothesise that this effect is specific for these disturbed sites and that at sites of low and no disturbance the effect decreases. Methods: We determined plant species richness, cover percentage of five functional groups, root (length) density, and biomass as well as soil aggregate stability, gravimetric soil moisture, soil density, and particle size distribution at different levels of disturbance (i.e. graded and un-graded ski slopes and the surrounding area). Results: Plant species richness, vegetation cover, aggregate stability and soil moisture were significantly reduced on machine-graded slopes compared to control plots but hardly on un-graded slopes. On the contrary, machine-grading increased soil density and friction angle compared to un-graded ski slopes. The influence of species richness on aggregate stability was only positive on gravely soils and graded ski slopes. Aggregate stability increased linearly up to approximately eight plant species, 70% vegetation cover and 0.006g cm−3 root density. Conclusions: Our study showed that the relationship between plant diversity and aggregate stability was strongest on slopes with high disturbance and relatively low species numbers. We suggest that high plant diversity, vegetation cover and root density need to be established after major human disturbance such as grading