Range change evolution of peat mosses (Sphagnum) within and between climate zones

Abstract

Peat mosses (Sphagnum) hold exceptional importance in the control of global carbon fluxes and climate because of the vast stores of carbon bound up in partially decomposed biomass (peat). This study tests the hypothesis that the early diversification of Sphagnum was in the Northern Hemisphere, with subsequent range expansions to tropical latitudes and the Southern Hemisphere. A phylogenetic analysis of 192 accessions representing the moss class Sphagnopsida based on four plastid loci was conducted in conjunction with biogeographic analyses using BioGeoBEARS to investigate the tempo and mode of geographic range evolution. Analyses support the hypothesis that the major intrageneric clades of peat‐forming species accounting for >90% of peat moss diversity originated and diversified at northern latitudes. The genus underwent multiple range expansions into tropical and Southern Hemisphere regions. Range evolution in peat mosses was most common within latitudinal zones, attesting to the relative difficulty of successfully invading new climate zones. Allopolyploidy in Sphagnum (inferred from microsatellite heterozygosity) does not appear to be biased with regard to geographic region nor intrageneric clade. The inference that Sphagnum diversified in cool‐or cold‐climate regions and repeatedly expanded its range into tropical regions makes the genus an excellent model for studying morphological, physiological, and genomic traits associated with adaptation to warming climates.

Latitudinal Biogeographic Structuring in the Globally Distributed Moss Ceratodon purpureus

“…Bipolar disjunctions are a distribution pattern characteristic of many bryophytes ( Ochyra et al, 2008 ), however recent molecular studies (e.g. Lewis et al, 2014a , 2017 ; Biersma et al, 2018b ; Shaw et al, 2019 ) suggest that trans-equatorial movements are infrequent events that happen very occasionally over hundreds of thousands to multi-million year timescales. Such trans-equatorial dispersal could have been facilitated by sporadic air movements or zoochory (adventitious attachment to other organisms, e.g.…”

Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists

“…While Sphagnum occurs at low as well as high latitudes it is only a dominant component of peatlands at higher latitudes (e.g., Tierra‐del‐Fuego and the boreal zone of the Holarctic). The taxonomic richness of the genus is low in the Southern Hemisphere high latitudes and high in the Northern Hemisphere high latitudes which correspond to its inferred origin (Shaw, Carter, Aguero, da Costa, & Crowl, ).…”

Morphological and biochemical responses ofSphagnummosses to environmental changes

“…We tested the presence of a phylogenic signal within anatomical and biochemical Sphagnum trait matrices by rejecting the null hypothesis that trait values for two species are distributed independently from their phylogenetic distance in the tree (Blomberg and Garland, 2002). Firstly, we built the phylogenic tree of our five Sphagnum species using the loci transfer RNA Gly (trnG) from GenBank (Shaw et al, 2020(Shaw et al, , 2019(Shaw et al, , 2010Weston et al, 2015). The FASTA sequences of the trnG gene were extracted from NCBI data base , and then assembled into a phylogenetic tree using the phylo4d function from the phylosignal R package (Keck et al, 2016).…”