Decoupling taxonomic and functional turnover in European peatlands Event

Abstract: Current projections on climate change may alter peatland carbon cycles, through changes in environmental conditions or by alterations in the plant community composition. Our understanding on the effects of climate change on C cycles is growing, yet the mechanism underlying apparent plant controls are not fully known.  In the first part of this presentation we present the results from a plant functional type removal study aiming to understand the role of vascular plant functional groups on peatland carbon cycling. The second part of the presentation will focus on the effects of environmental change on plant community composition and its consequences for the functional composition of the peatland plant community. We show that plant community composition strongly drives the composition of the microbial community, with subsequent consequences for carbon dioxide and methane turnover. Using plant community composition data from 56 peatlands across Europe, we show that plant community composition is largely affected by environmental conditions. Surprisingly, plant species aggregate in two major clusters based on their response to environmental conditions. Both clusters show distinct but contrasting responses to temperature, precipitation and atmospheric deposition, indicating a strong cluster–specific environmental filtering. The observed species turnover across these environmental gradients did, however not result in a change in the plant community functional identity, nor in its functional redundancy. Our results suggest a cluster–specific species substitution to underlie the conservation of functional redundancy at the community level along the environmental gradients. In other words, species loss by environmental filtering appears to be compensated by a deterministic gain of functionally alike species. Taken together, our results show taxonomic and functional turnover to be decoupled, which may indicate a high robustness of peatland ecosystem functioning to future environmental changes.