DOI: 10.5061/dryad.62054
title: Data from: Photosynthesis, growth, and decay traits in Sphagnum – a multispecies comparison

description: Peat mosses (Sphagnum) largely govern carbon sequestration in Northern
 Hemisphere peatlands. We investigated functional traits related to growth
 and decomposition in Sphagnum species. We tested the importance of
 environment and phylogeny in driving species traits and investigated
 trade-offs among them. We selected 15 globally important Sphagnum species,
 representing four sections (subgenera) and a range of peatland habitats.
 We measured rates of photosynthesis and decomposition in standard
 laboratory conditions as measures of innate growth and decay potential,
 and related this to realized growth, production, and decomposition in
 their natural habitats. In general, we found support for a trade-off
 between measures of growth and decomposition. However, the relationships
 are not strong, with r ranging between 0.24 and 0.45 for different
 measures of growth versus decomposition. Using photosynthetic rate to
 predict decomposition in standard conditions yielded R2 = 0.20. Habitat
 and section (phylogeny) affected the traits and the trade-offs. In a wet
 year, species from sections Cuspidata and Sphagnum had the highest
 production, but in a dry year, differences among species, sections, and
 habitats evened out. Cuspidata species in general produced easily
 decomposable litter, but their decay in the field was hampered, probably
 due to near-surface anoxia in their wet habitats. In a principal
 components analysis, PCA, photosynthetic capacity, production, and
 laboratory decomposition acted in the same direction. The species were
 imperfectly clustered according to vegetation type and phylogeny, so that
 some species clustered with others in the same section, whereas others
 clustered more clearly with others from similar vegetation types. Our
 study includes a wider range of species and habitats than previous trait
 analyses in Sphagnum and shows that while the previously described
 growth–decay trade-off exists, it is far from perfect. We therefore
 suggest that our species-specific trait measures offer opportunities for
 improvements of peatland ecosystem models. Innate qualities measured in
 laboratory conditions translate differently to field responses. Most
 dramatically, fast-growing species could only realize their potential in a
 wet year. The same species decompose fast in laboratory, but their
 decomposition was more retarded in the field than that of other species.
 These relationships are crucial for understanding the long-term dynamics
 of peatland communities.
description: Sphagnum trait
 dataTrait data from 15
 species in the bryophyte genus Sphagnum collected in field and laboratory.
 Descriptions of column headings available in the file
 bengtsson_etal_2016_traits_meta_v2.csvbengtsson_etal_2016_traits.csvbengtsson_etal_2016_traits_meta_v2.csvSphagnum phylogenetic treeBest fit phylogenetic tree showing relationships among 41 species of the genus Sphagnum. The tree was summarized from 1000 posterior trees (presented in Johnsson et al. 2015 Evolution, Data DOI: http://dx.doi.org/10.5061/dryad.0p36h/3) using the software treeAnnotator. In our study this tree was pruned to just include the 15 species of interest, using the drop.tip function in the R package ape.sph.tree