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Abstract Detail



Bryological and Lichenological Section/ABLS

Hedenas, Lars [1].

Mosses in a system of Scandinavian interglacial refugia.

The Scandinavian Peninsula (NW Europe) was almost completely covered by ice during the Last Glacial Maximum, and extant intraspecific patterns among regional populations of plants potentially reflect pre-glacial, glacial, and late- to postglacial differentiation and dispersal. Cold-adapted species are today restricted to traditional interglacial refugia at high latitudes and along the Scandinavian mountain range at lower latitudes. However, some poor competitors that were widespread during glacial periods and that stand both cold temperatures and other habitat conditions that are detrimental to strong competitors occur also at low-latitude cryptic lowland refugia during interglacial periods.
A highly interesting system of interglacial refugia and cryptic lowland refugia for plant species that grow in more or less calcareous habitats and that depend on conditions with low competition exists in the Scandinavian Peninsula and its close surroundings. I investigated six dioicous moss species that occur mainly in this system to evaluate the suitability of the system for studies of factors influencing intraspecific diversity and structure. Based on sequence data, I review features, such as, regional intraspecific haplotype diversity, Tajima’s D (potentially indicating population increase or decrease), and similarities in haplotype composition among regional populations. Two of the species are restricted to lowland regions (1) and four species occur both in the mountains and the lowlands (2). The species further differ in their frequency of sporophyte production and means of asexual propagation. In the first category, Drepanocladus lycopodioides, is endemic to W Eurasia and has strong extant occurrences mainly in the Baltic region, whereas Tortella rigens has at least 95% of its globally known occurrences in southern Scandinavia. Both species display clear regional differentiation. Species of the second category are more widespread globally. For Hypnum bambergeri and H. vaucheri only limited intraspecific variation was found, whereas Drepanocladus turgescens and Rhytidium rugosum both displayed clear differences among regional populations. These studies show that several species display sufficient variation to justify more detailed investigations into which factors have shaped their intraspecific variation. In a next step, a more detailed study of Rhytidium rugosum to explore potential sources of its postglacial colonization of Scandinavia is under way, and I will also present some results from this investigation.


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1 - Swedish Museum of Natural History, Department of Botany, Box 50007, Stockholm, -, SE-10405, Sweden

Keywords:
Phylogeography
Molecular divergence
Postglacial history
Haplotype.

Presentation Type: Oral Paper:Papers for Sections
Session: 38
Location: Salon 8/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 10:15 AM
Number: 38007
Abstract ID:99
Candidate for Awards:None


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