PARENT SESSION
Poster Session 11: Disturbance Ecology
Tuesday, August 9, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Evolution of branch propagation under heavily disturbed environments.
Miki, Takeshi*,1, Kobayashi, Yutaka1, Nakamura, Masahiro2, 1 Center for Ecological Research, Kyoto University, Otsu, Shiga, Japan2 Institute of Low Temperature Science, Hokkaido University, Sapporo, Hokkaido, Japan
ABSTRACT- Some woody plants have a dispersive form of vegetative regeneration, propagation through fragmented branches (branch propagation), taking advantage of physical impacts of disturbances such as floods. However, there are observed inter-specific or spatial variations in the ability of branch propagation. In order to explain these variations from the points of adaptive strategy against disturbances, we proposed a hypothetical persistence/colonization trade-off, by introducing the fragility as an evolutionary trait of plants. We assumed that plants with high fragility are able to produce many vegetative branches (high colonization ability), but at the same time, suffer from high mortality with disturbances (low persistence against disturbances). Using a simple population genetics model with one-locus and two alleles, we examined the dependence of the evolutionarily stable (ES) fragility on the severity of disturbances. We defined the fragility (f) as the probability with which individuals are killed by each disturbance, and the severity of disturbances (D) as the probability with which each individual suffers from disturbances per each generation. We predicted the shifts of ES fragility among three strategies with the changes in the severity of disturbance: extremely high fragility with lowest seed production, extremely low fragility with no branch propagation, and intermediate fragility with which plants rely on both of seed production and branch propagation. The patterns of evolutionary shifts with the severity are dependent of the relationship between the fragility and the ability of branch propagation and the potential contribution of branch propagation to lifetime reproductive output.
Key words: disturbance, persistence/colonization trade-off, mathematical model