Data from: Plant community dynamics and carbon sequestration in Sphagnum-dominated peatlands in the era of global change

Aim: Hydroclimatic shift and anthropogenic-driven nitrogen deposition are
major outcomes of global change that could compromise the functioning of
many peatlands as a carbon sink. For Sphagnum-dominated peatlands, an
emerging hypothesis is that the change could be triggered by shifts in
competitive dominance among plant functional groups, specifically from the
currently predominant decay-resistant Sphagnum to the more decomposable
vascular plants. However, the relationship between Sphagnum and vascular
plant occurrence is notably complex and also includes facilitative
interactions that are crucial to the productivity of Sphagnum and
therefore carbon sequestration. Location: Global Taxa: Northern
peatlands—Sphagnum moss and vascular plants Methods: We use a conceptual
review to examine underlying mechanisms for the competitive exclusion
hypothesis and the nature of facilitative interactions between Sphagnum
and vascular plants under the potential global change conditions. We
complement the review with an empirical study of peatlands with
contrasting hydrology to provide some critical insights into the potential
effects of change in plant communities on carbon sequestration. We also
propose a conceptual model that presents probable combinations of global
change factors and their implications for carbon sequestration. Results:
Vegetation structure in Sphagnum-dominated peatland appears to be driven
largely by hydrology, rather than competition among plant functional
groups. The peat deposit also exerts some controls (e.g., nutrient
immobilization) on biotic structure, thereby acting as resistance against
an abrupt shift in plant communities. Main conclusions: Peatland controls
that constrain vegetation shifts have developed over a millennial
timescale in many peatlands, and the pace of climate change may not allow
enough time for the establishment of those mechanisms in younger
peatlands. Thus, the persistence of a given peatland as a carbon sink also
likely depends on the successional stage of the peatland.