Abstract:
Aim To explore the relative effects of Quaternary climatic history vs. speciesspecific biological properties (high seed dispersability, high seed longevity, clonal
growth) on phylogeographical structure in European Mediterranean and Atlantic
Ocean and Black Sea material of the coastal dune plant Calystegia soldanella (L.)
R. Br.
Location Black Sea and European Mediterranean and Atlantic Ocean coasts.
Methods Variation in amplified fragment length polymorphism was analysed at
two different sampling levels. First, an entire-range sample from the Black Sea to the
North Sea, including single individuals from sites evenly spread along this entire
coast was analysed. Second, in a population-level sample, seven populations from
the European Mediterranean and Atlantic Ocean coasts were analysed.
Results Neither the entire-range nor the population-level sampling resulted in
clear phylogeographical patterns. Instead, individuals from geographically distant
areas were often genetically more similar to each other than individuals from the
same area. Non-significant isolation-by-distance was found for both sampling
approaches, and comparatively low levels of intrapopulational genetic variation
were observed.
Main conclusions The lack of phylogeographical structure in C. soldanella, in
comparison with the clear phylogeographical patterns observed in other coastal
plant species analysed previously, is postulated to be the result of the specific biology
of C. soldanella. The combination of high seed longevity, high dispersability of seeds
by sea water and clonal growth and probable high clone age are likely to be
responsible for the observed absence of phylogeographical structure. This implies
that extreme biological properties such as those shown by C. soldanella can either
erase or prevent the formation of historical patterns of genetic variation
