Phylogeography of Alpine populations of Rhytidium rugosum (Bryophyta) in a European context

Abstract

The phylogeography and possible origins of the moss Rhytidium rugosum (Hedw.) Kindb. in the European Alps are studied based on information from the nuclear internal transcribed spacers 1 and 2 and a portion of the gene region for glyceraldehyde 3-phosphate dehydrogenase for 364 European specimens. Seventy-three Alps specimens were sampled from W Switzerland to W Austria, and were divided into four regional populations along a WestSouth-West (WSW) to East-North-East (ENE) gradient. These populations were compared with similar ones previously studied in other parts of Europe. The ENE-most Alps population, located ENE of the Adige break zone, deviates genetically from the other three. The two WSWmost populations of the Alps appear to be relatively isolated from most of the European populations outside the Alps, whereas the two ENE ones are similar to populations of northern Scandinavia. Populations in between the Alps and the Scandinavian mountain range deviate from those to the north and south, possibly due to low effective population sizes, earlier bottleneck events, or colonization from different source populations. Haplotype diversity and number of private haplotypes are marginally higher in the Alps than in Scandinavia. It is suggested that European Rhytidium originated from late glacial maximum refugia in (1) E-NE Europe, (2) in between the Late Glacial Maximum ice shields of Scandinavia and the Alps, and (3) S, SW, and W of the Swiss Alps. Those of the E Alps potentially originated mainly in E-NE Europe and those of the W Alps in the S, SW, and W.

Life-history characteristics and historical factors are important to explain regional variation in reproductive traits and genetic diversity in perennial mosses

“…Genetic diversity in the two species was comparable to that in previously studied bryophytes (e.g. Szövényi et al , 2006 ; Hedenäs, 2017 ). Overall, genetic diversity ( H , π n ), the number of effective haplotypes and number of private haplotypes per region were higher in D. turgescens than in D. trifarius .…”

“…Our data thus do not support the third prediction of lower genetic diversity in areas with rare rather than regular sexual reproduction. In D. turgescens , the proportion of genetic variation between regions was significant, albeit limited (4 %; Table 4 ), and was in the lower range of interregional differentiation observed in other plant species ( Zhang et al , 2005 ; Hedenäs, 2017 ). Previous studies of different plant species reported that genetic variation could also be retained in predominantly clonal populations, depending on the colonization history of a species (e.g.…”

“…Different historical factors, such as founder events, glaciation history, climate fluctuation or immigration routes, have indeed been shown to influence regional variation in reproductive traits at various scales (e.g. Alsos et al , 2005 ; Field et al , 2013 b ; Hedenäs, 2017 ; Carter, 2021 ; Boquete et al , 2023 ). Finally, such differences are likely to be reflected in sex-related patterns of genetic diversity and genetic structure ( Dering et al , 2016 ; Zhai et al , 2016 ).…”

Using a new database of plant macrofossils of the Czech and Slovak Republics to compare past and present distribution of hypothetically relict fen mosses

“…One of the possible applications of macrofossil databases is tracing the species distribution dynamics during glacial/interglacial cycles. Many studies have reconstructed glacial refugia and post-glacial recolonization patterns of individual species at the European scale, including bryophytes (Szövenyi et al 2006, Kyrkjeeide et al 2012, Hedenäs 2017. In central and western Europe, there is a long tradition of identifying which of the regionally rare species are relicts from glacial times, or at least from before the middle-Holocene climate optimum (so called 'glacial relicts' in this concept; see Rybníček 1966, Jankovská 1988, Odgaard 1988.…”