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Temporal and spatial genetic variation in a metapopulation of the annual Erysimum cheiranthoides on stony river banks
Author(s) -
Honnay Olivier,
Jacquemyn Hans,
Van Looy Kris,
Vandepitte Katrien,
Breyne Peter
Publication year - 2009
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1111/j.1365-2745.2008.01452.x
Subject(s) - metapopulation , variation (astronomy) , ecology , geography , biology , demography , biological dispersal , physics , population , sociology , astrophysics
Summary1 Metapopulation dynamics – the recurrent extinction and colonization in spatially discrete habitats – is expected to strongly affect within and between population genetic diversity. So far, however, accounts of true plant metapopulations are extremely scarce. 2 We monitored the colonization and extinction dynamics of an assemblage of populations of the annual Erysimum cheiranthoides on stony river banks during three consecutive years. Each year, winter flooding drives some populations to extinction, while vacant banks may become colonized. We describe the dynamics of these ephemeral populations using amplified fragment length polymorphism (AFLP) markers to quantify changes in the metapopulation genetic structure over time, and assessing the direction and relative amount of migration and colonization events. 3 Average extinction and colonization rates were high (0.39 and 0.34, respectively). While population genetic differentiation ( F ST ) tripled from 0.06 in 2005 to 0.17 in 2007, total metapopulation genetic diversity remained fairly constant through the years. Genetic assignment analyses allowed assigning more than 50% of the genotyped individuals to populations extant the year before. Colonizing individuals originated from different source populations ( ϕ << 1) and there was considerable evidence of upstream seed dispersal. 4 The degree and pattern of spatial genetic structure varied between years and was related to variation in the flooding intensity of the Meuse River through the years. Possibly, activation of the soil seed bank also played a role in structuring the genetic make‐up of the populations. 5 Because migration and colonization events were qualitatively equal, and colonizing individuals originated from different sources, the increase in F ST was in agreement with previous theoretical work. Very high migration and colonization rates, and the short monitoring period, may explain why there was no loss of genetic diversity from the metapopulation through recurrent extinction and colonization events. 6 Synthesis. This study gives one of the first accounts of the dynamics of a true plant metapopulation. Temporal monitoring of genetic variation gave evidence of extensive and bidirectional seed dispersal, highly variable and increasing genetic differentiation, and rather constant within population genetic diversity. An important suggestion from this research is to include a dormant seed stage in further theoretical work on (meta) population genetics.