Scaling of processes shaping the clonal dynamics and genetic mosaic of seagrasses
through temporal genetic monitoring |
| |
Authors: | R Becheler E Benkara Y Moalic C Hily S Arnaud-Haond |
| |
Institution: | 1.Institut Français de Recherche sur la
MER (IFREMER)-Département ‘Etude des Ecosystèmes Profonds''-
DEEP, Centre de Brest, Plouzané Cedex, France;2.Institut Universitaire Européen de la
MER (IUEM)-Laboratoire des sciences de l''Environnement Marin, Plouzanè, France |
| |
Abstract: | Theoretically, the dynamics of clonal and genetic diversities of clonal plant populations
are strongly influenced by the competition among clones and rate of seedling recruitment,
but little empirical assessment has been made of such dynamics through temporal genetic
surveys. We aimed to quantify 3 years of evolution in the clonal and genetic composition
of Zostera marina meadows, comparing parameters describing clonal architecture
and genetic diversity at nine microsatellite markers. Variations in clonal structure
revealed a decrease in the evenness of ramet distribution among genets. This illustrates
the increasing dominance of some clonal lineages (multilocus lineages, MLLs) in
populations. Despite the persistence of these MLLs over time, genetic differentiation was
much stronger in time than in space, at the local scale. Contrastingly with the short-term
evolution of clonal architecture, the patterns of genetic structure and genetic diversity
sensu stricto (that is, heterozygosity and allelic richness) were stable in
time. These results suggest the coexistence of (i) a fine grained (at the scale of a 20
× 30 m quadrat) stable core of persistent genets originating from an initial
seedling recruitment and developing spatial dominance through clonal elongation; and (ii)
a local (at the scale of the meadow) pool of transient genets subjected to annual
turnover. This simultaneous occurrence of initial and repeated recruitment strategies
highlights the different spatial scales at which distinct evolutionary drivers and mating
systems (clonal competition, clonal growth, propagule dispersal and so on) operate to
shape the dynamics of populations and the evolution of polymorphism in space and time. |
| |
Keywords: | clonality seagrass spatio-temporal genetic structure Zostera marina |
|
|