Anthropogenic and natural disturbances increase local genetic diversity
in an early spring geophyte (Ficaria verna Huds.)
Abstract
Tetraploid Ficaria verna is a common spring geophyte that forms large
populations in central Europe and is considered invasive in northern USA
and Canada. It is considered an almost seed-sterile taxon, relying on
vegetative reproduction by underground tubers and aerial bulbils. Recent
studies have revealed high levels of population genetic diversity in F.
verna, raising the question of how genetic diversity is maintained and
which factors may be responsible for the observed patterns. Polymorphic
nuclear microsatellite markers were established to define multi-locus
genotypes (MLGs), to analyze fine-scale spatial genetic structure (SGS)
using grid and cross sampling schemes, and to quantify genetic diversity
within and between nine populations with different disturbance regimes
in central Germany. 115 MLGs were identified among a total of 347
samples. The G/N ratio varied between 0.16 and 0.70 among populations,
and in each population a number of unique MLGs occurred. Genotypes were
highly intermingled within populations, suggesting a ‘guerrilla’
dispersal strategy. Significant negative SGS was found in five out of
nine populations in fine-scale cross sampling (up to 4 m) and in only
one population in grid sampling (up to 14.6 m). No single MLG was found
in more than one population, while many alleles were shared between
populations. Within-population genetic diversity increased with greater
exposure to both anthropogenic and natural disturbances. Regular gap
openings, facilitated propagule establishment (vegetative and sexual),
and propagule dispersal by water and mowing machines are likely
important factors explaining the positive effects of disturbance on
local genetic diversity of F. verna.