Alpine Soil Temperature Variability at Multiple Scales

Abstract

The functioning of ecosystems is strongly correlated to soil temperature dynamics. Because only a few studies so far have investigated the spatio-temporal variability of alpine soil temperatures, we proceeded to analyze soil temperatures in a heterogeneous alpine landscape by means of a multi-scale approach. We combined vertical soil temperature gradients from surface to 15 cm depth, microspatial variability within small catchments, and altitudinal changes of a continental mountain system. We analyzed differences at single sites and at multiple spatial scales. We found that microtopographic site conditions dominated thermal changes along altitudinal gradients. The adiabatic lapse rate did not show high correlations with local soil temperature gradients. We used isopleth diagrams of soil temperature gradients and corresponding scatterplots of soil temperature gradients between each pair of sites and low alpine–middle alpine mountain couples to quantify these overlying phenomena. This enabled us to quantify the significance of soil temperature gradients across vertical soil profiles, topography, and altitude in order to facilitate future microclimate extrapolation and modeling in high mountain (alpine) landscapes. Such procedures are crucial for describing expected responses of alpine ecosystems to global climatic change.