Impacts of twenty years of experimental warming on soil carbon, nitrogen, moisture and soil mites across alpine/subarctic tundra communities

Juha M Alatalo,Peter Ľuptáčik,Jaanis Juhanson,Annika K Jägerbrand,Anders Michelsen

doi:10.1038/srep44489

Abstract

High-altitude and alpine areas are predicted to experience rapid and substantial increases in future temperature, which may have serious impacts on soil carbon, nutrient and soil fauna. Here we report the impact of 20 years of experimental warming on soil properties and soil mites in three contrasting plant communities in alpine/subarctic Sweden. Long-term warming decreased juvenile oribatid mite density, but had no effect on adult oribatids density, total mite density, any major mite group or the most common species. Long-term warming also caused loss of nitrogen, carbon and moisture from the mineral soil layer in mesic meadow, but not in wet meadow or heath or from the organic soil layer. There was a significant site effect on the density of one mite species, Oppiella neerlandica, and all soil parameters. A significant plot-scale impact on mites suggests that small-scale heterogeneity may be important for buffering mites from global warming. The results indicated that juvenile mites may be more vulnerable to global warming than adult stages. Importantly, the results also indicated that global warming may cause carbon and nitrogen losses in alpine and tundra mineral soils and that its effects may differ at local scale.

Highlights

Soil mites play a vital role in several soil processes and are important for ecosystem functioning and carbon cycling[12,18]
Long-term warming had no significant impact on soil parameters in the mineral soil layer in the heath and wet meadow (Fig. 2), but a significant negative effect on total N (p = 0.029), C (p = 0.029) and soil moisture (p = 0.029), a positive effect on C/N ratio (p = 0.029) and a near-significant positive impact on pH (p = 0.057) in the mineral soil layer of the meadow (Fig. 2)
No effects were found on the organic soil layer of the mesic meadow or in the mineral and organic soils layers of the wet meadow and poor heath communities

Summary

Introduction

Soil mites play a vital role in several soil processes and are important for ecosystem functioning and carbon cycling[12,18]. Previous studies on the effects of experimental climate warming on microarthropods report contrasting responses, from increased mite densities in polar ecosystems[13,14,16] to no response[25,26]. These responses are suggested to be both habitat- and group-specific[27]. We examined the impact of 19 and 21 years of experimental warming, field site and plot scale on soil parameters (soil carbon (C), nitrogen (N), C/N ratio, moisture and pH in the organic and mineral soil layers), total mite density, juvenile and adult stages of mites, density of major mite groups and the most common species of oribatid mites in three contrasting alpine/ subarctic plant communities

Methods

Results

Conclusion