Characterization of alpine pine soil climosequences by high-throughput techniques

Mountain ecosystems represent a unique and ideal scenarios for the study of climate impacts due to their sensitivity and responsiveness to environmental changes. A climosequence on acidic paragneiss parent material, comprising 5 pairs of north- and south-facing sites (three 5x5 m plots each) across an altitudinal gradient (1200-2400 m above sea level) in an Alpine setting in Val di Rabbi (Trentino, Italy) was studied. Five soil sub-samples were randomly taken in each plot at 0-5, 5-10 and 10-15 cm, rendering a total of 450 samples, all of which were first subjected to a crude (not purified) dsDNA-based microbial biomass quantitation and a desorption-based multiple enzyme assay. Soil chemical and microbial parameters (microbial community structure and abundance of bacteria, fungi and archaea assessed by PCR-DGGE and real-time PCR, respectively) were determined as well. Overall, our findings showed that the abundance, composition and activity of the soil microbiota was affected by the exposure but the exposure-effect was altitude-dependent. Moreover, information about the heterogeneous distribution of the soil microorganisms at a small scale was obtained. The discrimination among the multiple-factor effects (biotic and abiotic factors) on the soil microbiota across this climosequence scenario was feasible because we exploited the advantages of simple, low-cost but powerful methods (enzymes and dsDNA) capable to provide clear indications on a large and thus representative number of samples.