Genetic diversity in adult and seedling populations of <Emphasis Type="Italic">Primula vulgaris</Emphasis> in a fragmented agricultural landscape |
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Authors: | Anja Van Geert Fabienne Van Rossum Ludwig Triest |
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Institution: | (1) Plant Biology and Nature Management, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium;(2) Present address: Department of Vascular Plants, National Botanic Garden of Belgium, Domein van Bouchout, Meise, 1860, Belgium |
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Abstract: | Habitat fragmentation is known to generally reduce the size of plant populations and increase their isolation, leading to
genetic erosion and increased between-population genetic differentiation. In Flanders (northern Belgium) Primula vulgaris is very rare and declining. Populations have incurred strong fragmentation for the last decades and are now restricted to
a few highly fragmented areas in an intensively used agricultural landscape. Previous studies showed that small populations
of this long-lived perennial herb still maintained high levels of genetic variation and low genetic differentiation. This
pattern can either indicate recent gene flow or represent historical variation. Therefore, we used polymorphic microsatellite
loci to investigate genetic variation and structure in adult (which may still reflect historical variation) and seedling (recent
generation, thus affected by current processes) life stages. The recent generation (seedlings) showed a significant loss of
observed heterozygosity (H
o) together with lower expected heterozygosity (H
e), a trend for higher inbreeding levels (F
IS) and higher differentiation (F
ST) between populations compared to the adult generation. This might result from (1) a reduction in effective population size,
(2) higher inbreeding levels in the seedlings, (3) a higher survival of heterozygotes over time due to a higher fitness of
heterozygotes (heterosis) and/or a lower fitness of homozygotes (inbreeding depression), (4) overlapping generations in the
adult life stage, or (5) a lack of establishment of new (inbred) adults from seedlings due to degraded habitat conditions.
Combining restoration of both habitat quality and gene flow between populations may be indispensable to ensure a sustainable
conservation of fragmented populations. |
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Keywords: | Genetic erosion Habitat fragmentation Inbreeding Long-lived perennial Microsatellites |
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