Abstract Detail



Ecology

Velichka, Jenni [1], Friedman, Jannice [2].

Intraspecific variation in seed dispersal strategies between annual and perennial ecotypes of Mimulus guttatus.

Seed dispersal affects gene flow, demographic processes, and fitness by influencing the habitat and distribution of a plant’s offspring. Differences in life form, specifically annuality versus perenniality, may favour different dispersal strategies. Perennials often live in more competitive environments that can be crowded due to clonal reproduction. In addition, in iteroparous perennials the parent plant may compete with its offspring in subsequent years. Therefore, we hypothesized that perennials should disperse their seed farther to avoid competition. We tested this using 40 individuals from each of 3 annual and 3 perennial populations of Mimulus guttatus (syn. Erythranthe guttata)and compared the orientation of their reproductive structures at flowering and again at seed set, and measured seed dispersal using wind trials. We found that the orientation of the reproductive structures shifted downward from flowering to seed set in both ecotypes, suggesting that an upward orientation is important for flowering (e.g. orientation for pollinators), while a downward orientation facilitates dispersal. However, perennials had less change in the angle between flowering and seed set and oriented their seed pods more upward, which elevates the height of release and better retains seeds. Additionally, using wind trials at two wind speeds (~2.5m/s and ~ 3m/s) we found that perennials dispersed their seed farther distances and retained a greater proportion of seed after the trials. This supports abscission bias, where seed pods require a larger force to dislodge the seed, consequently carrying the seed farther. Overall, our results suggest that perennials are adapted for farther seed dispersal compared to annuals in Mimulus gutattus. Interactions between dispersal and ecotypic variation can help understand gene flow, range shifts and population demographics.


1 - Queen's University, Biology, 116 Barrie Street, Kingston , ON, K7L 3N6, CAN
2 - Queen's University, Biology Department, Biosciences Complex , 116 Barrie Street, Kingston, ON, K7L 3N6, Canada

Keywords:
life history
seed dispersal
reproduction
wind dispersal
morphology.

Presentation Type: Oral Paper
Number: ECO2001
Abstract ID:490
Candidate for Awards:Ecological Section Best Graduate Student Paper


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