Plant expansion drives bacteria and collembola communities under winter climate change in frost-affected tundra
The research was conducted by our researchers at CIRC in collaboration with researchers from the Swedish University for Agricultural Sciences. Our researchers investigated how our soil will react to winter warming which means increased temperatures during the winter time and consequently an increased growing period for the plants. Thus, they observe more vegetation growing in formerly bare areas. The interplay of winter warming and the resulting plant presence may change soil properties. Decomposers in the soil might be affected through the new plant material. In this paper, the researchers looked at the way in which different decomposers and microorganisms react to the new plant material.
With an experiment, the effects of increased vegetation, (1) thermal insulation and (2) increased snow accumulation around the plants, were simulated. (1) Patches of soil were covered with insulating gardening fibre cloth (fleeces) and (2) stone walls were used to foster artificial accumulation of snow. Since these changes occur in the winter, we will observe changes in the summer time. Thus, microorganisms present in summer were sampled.
Two years of winter warming had no effects on the sampled decomposer communities. Instead, their community compositions were strongly determined by sampling location. Two types of decomposers could be linked to physical properties of the sampling locations through diversity patterns. Collembola communities are tightly linked to plant presence while bacteria communities correlated with soil properties.
The results suggest that direct effects of short-term winter warming are likely to be minimal, but that vegetation expansion on barren ground will affect the composition of decomposer communities substantially. At decadal timescales, collembola community changes may occur relatively fast compared to changes in bacteria communities. The next anticipated steps are to find out if the observed changes in decomposer community composition indicate changes in their activity also. Consequently, vegetation expansion will likely have strong effects on the functioning of tundra soil.
E. Krab, S. Monteux, J. Weedon, E. Dorrepaal, Plant expansion drives bacteria and collembola communities under winter climate change in frost-affected tundra, Soil Biology and Biochemistry, 2019, DOI