Re-vegetation seems like a beneficial strategy for conserving and restoring damaged ecosystems, and using a variety of species can help increase biodiversity in these systems. But what are the risks involved with introducing seeds from other locations to plants located near the damaged site? Introduced populations often hybridize with the local populations from the same species, which can result in "polluting" neighboring populations with genes that are poorly adapted to local conditions. Long-term consequences of such "pollution" could negatively impact the survival of the existing native populations.
A recent article in the January issue of the American Journal of Botany by Lisle Crmieux and colleagues from the University of Fribourg in Switzerland (http://www.amjbot.org/cgi/content/full/97/1/94) looks at how gene flow from two distant populations and one local, but ecologically distinct, population affected a local population of Plantago lanceolata, a short-lived perennial herb. Seedling size, adult vegetative biomass, and estimated seed production were measured for two hybrid generations plus the first generation backcrossed with the local parents.
"We wanted to know whether the provenance of the seed material used in ecosystem restoration had an effect on the fitness of neighboring, locally adapted, populations," Crmieux said, "and not only on the success of the restored area itself."
The farther away two populations are, the larger the genetic differences are assumed to be and the more negative the consequences of hybridizing them. Crmieux and colleagues found that by the end of the growing season, the parental plants from the two distant (foreign) populations were smaller and produced fewer seeds than the local plants, indicating they were not well-adapted to the local environment. However, while the first generation of offspring resulting from local plant
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American Journal of Botany