Influence of inbreeding depression on a lake population of Nymphoides peltata after restoration from the soil seed bank
The negative effects of inbreeding depression on fragmented small populations are likely to be expressed more strongly after restoration efforts if regeneration processes have been highly restricted in degraded habitats. We examined the potential influences of inbreeding depression on a population of Nymphoides peltata (Menyanthaceae) restored from the remnant soil seed bank. A hand-pollination experiment demonstrated self-compatibility of a single remaining homostyle genet and significant inbreeding depression in selfed progeny, especially in parameters related to seedling growth (\(\updelta=0.5\)–0.6 for biomass, and \(\updelta=0.3\)–0.4 for relative growth rate). Our genetic analysis indicated that the presumed number of parents contributing to the current soil seed bank was only 2–8 genets and that a single sib-family dominated at each of three sampling sites. The results also showed that the selfed progeny of the homostyle genet were overwhelmingly dominant at two sites (86.8 and 94.7%). As a result, the growth performance of the seed bank seedlings was significantly reduced, to a level as low as that of the selfed progeny. Active restoration efforts to minimize the negative effects of the genetic bottleneck and continuous monitoring based on genetic and demographic study are recommended.
Key wordsbottleneck inbreeding depression microsatellite offspring fitness restoration soil seed bank
Unable to display preview. Download preview PDF.
We thank the Kasumigaura River Office of MLIT (Ministry of Land, Infrastructure and Transport, Government of Japan) and the Japan Water Agency for permitting the use of plant materials and their experiment station for our hand-pollination experiment. We also thank J. Nishihiro, F. Ishihama, M. Honjo, and two anonymous reviewers for their valuable comments on the manuscript. This research was partly supported by a Grant-in-Aid for Fellows of the Japan Society for the Promotion of Science (17-52322).
- Barrett SC, Kohn JR (1991). Genetic and evolutionary consequences of small population size in plants: Implications for conservation. In: Falk DA, Holsinger KE (eds). Genetics and Conservation of Rare Plants. Oxford University Press, New York, pp. 3–30Google Scholar
- Eckert CG, Barrett SCH (1994). Post-pollination mechanisms and the maintenance of outcrossing in self-compatible, tristylous, Decodon verticillatus (Lythraceae). Heredity 72:396–411Google Scholar
- Environment Agency of Japan (2000) Threatened wildlife of Japan—Red data book, 2nd edn. Vascular plants, vol. 8. Japan Wildlife Research Center, Tokyo.Google Scholar
- Glück H (1924). Biologische und morphologishe Untersuchungen über Wasser- und Sumpfgewächse. IV. Untergetauchte und Schwimmblattflora. Gustav Fischer, JenapGoogle Scholar
- Goudet J (2001) FSTAT, a program to estimate and test gene diversities and fixation indices (ver 2.9.3). Available from 〈http://www.2.unil.ch/popgen/softwares/fstat.htm〉.Google Scholar
- Hoffman AA, Parsons PA (1997). Extreme Environmental Change and Evolution. Cambridge University Press, CambridgeGoogle Scholar
- Marui H, Washitani I (1993). Heterostyly and seed production of Nymphoides peltata in Lake Kasumigaura (In Japanese). Syuseibutsugaku Kenkyu 17:59–63Google Scholar
- Middleton B (1999). Wetland restoration: Flood pulsing and disturbance dynamics. John Wiley & Sons, New YorkGoogle Scholar
- Oostermeijer JGB (2000). Population viability analysis of the rare Gentiana pneumonanthe: The importance of genetics, demography and reproductive biology. In: Young AG, Clarke GM (eds). Genetics, demography and viability of fragmented populations. Cambridge University Press, Cambridge, pp. 313–334Google Scholar
- Oostermeijer JGB, van Eijck MW, den Nijs JCM (1994). Offspring fitness in relation to population size and genetic variation in the rare perennial plant species Gentiana pneumonanthe (Gentianaceae). Oecologia 97:289–296Google Scholar
- Presciuttini S, Toni C, Tempestini E, Verdiani S, Casarino L, Spinetti I, De Stefano F, Domenici R, Bailey-Wilson JE (2002) Inferring relationships between pairs of individuals from locus heterozygosities. BMC Genetics, 3Google Scholar
- Raymond M, Rousset F (1995). Genepop (version-1.2): Population genetics software for exact tests and ecumenicism. J. Hered 86:248–249Google Scholar