Plant expansion drives bacteria and collembola communities under winter climate change in frost-affected tundra

Krab, Eveline J.; Monteux, Sylvain; Weedon, James T.; Dorrepaal, Ellen

doi:10.1016/J.SOILBIO.2019.107569

Title

Plant expansion drives bacteria and collembola communities under winter climate change in frost-affected tundra

Author

Krab, Eveline J.

Monteux, Sylvain

Weedon, James T.

Dorrepaal, Ellen

Abstract

At high latitudes, winter warming facilitates vegetation expansion into barren frost-affected soils. The interplay of changes in winter climate and plant presence may alter soil functioning via effects on decomposers. Responses of decomposer soil fauna and microorganisms to such changes likely differ from each other, since their life histories, dispersal mechanisms and microhabitats vary greatly. We investigated the relative impacts of short-term winter warming and increases in plant cover on bacteria and collembola community composition in cryoturbated, non-sorted circle tundra. By covering non-sorted circles with insulating gardening fibre cloth (fleeces) or using stone walls accumulating snow, we imposed two climate-change scenarios: snow accumulation increased autumn-to-late winter soil temperatures (−1 cm) by 1.4 °C, while fleeces warmed soils during that period by 1 °C and increased spring temperatures by 1.1 °C. Summer bacteria and collembola communities were sampled from within-circle locations differing in vegetation abundance and soil properties. Two years of winter warming had no effects on either decomposer community. Instead, their community compositions were strongly determined by sampling location: communities in barren circle centres were distinct from those in vegetated outer rims, while communities in sparsely vegetated patches of circle centres were intermediate. Diversity patterns indicate that collembola communities are tightly linked to plant presence while bacteria communities correlated with soil properties. Our results thus suggest that direct effects of short-term winter warming are likely to be minimal, but that vegetation encroachment on barren cryoturbated ground will affect decomposer community composition substantially. At decadal timescales, collembola community changes may follow relatively fast after warming-driven plant establishment into barren areas, whereas bacteria communities may take longer to respond. If shifts in decomposer community composition are indicative for changes in their activity, vegetation overgrowth will likely have much stronger effects on soil functioning in frost-affected tundra than short-term winter warming.

Language

English

Source (journal)

Soil biology and biochemistry. - Oxford

Publication

Oxford : 2019

ISSN

0038-0717

DOI

10.1016/J.SOILBIO.2019.107569

Volume/pages

138 (2019) , 12 p.