Flinn, Kathryn M. .
Selfing abilities of three fern species may contribute to differential colonization success in post-agricultural forests.
What makes some plant species more successful than others at colonizing new habitats? One trait long thought to facilitate colonization is the ability to self-fertilize, since it enables a single seed or spore to found a reproductive population (Stebbins, 1950; Baker, 1955). Still, few studies have documented associations between mating systems and colonization ability. Ferns are particularly interesting in this context because their wind-dispersed spores often reach new habitats, and their mating systems potentially include outcrossing, intergametophytic selfing (analogous to selfing in seed plants) and intragametophytic selfing (which has no analog in seed plants and yields fully homozygous progeny). In central New York, three common fern species have contrasting distributions across forests of different history. Polystichum acrostichoides is much more frequent in forests that were never cleared (primary forests); Dryopteris carthusiana is more frequent in forests developing on abandoned agricultural lands (secondary); and D. intermedia is equally frequent in the two forest types. I conducted an experiment to investigate whether different selfing abilities partly explain the differential colonization success of these species. From spores collected in three pairs of primary and secondary forests, I grew gametophytes either in isolation (allowing only intragametophytic selfing) or in pairs with other gametophytes of varying relatedness. In all conditions, D. carthusiana had the highest rates of survival to maturity and reproductive success, and P. acrostichoides the lowest. The species also responded differently to different levels of inbreeding. Isolated plants had greater reproductive success than paired plants in D. carthusiana, and they were equally successful in D. intermedia, whereas paired P. acrostichoides had greater reproductive success than isolated plants. These results support the hypothesis that selfing may facilitate colonization in these species.
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K.M. Flinn research page
1 - Cornell University, Department of Ecology & Evolutionary Biology, Corson Hall, Ithaca, New York, 14853, USA
Presentation Type: Oral Paper
Location: Salon A - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 2:30 PM