Abstract Detail



Ecological factors that drive patterns of population genetic structure in plants

Hendrickson, Elizabeth [1], Cruzan, Mitchell [2], Thompson, Pamela [3].

Local and regional seed movement in a wind-dispersed plant species.

Seed dispersal is a key ecological process that determines the geographic distribution of many plants. Landscape features can influence patterns of seed dispersal depending upon the seed dispersal syndrome. Wind-dispersed species have the potential to be transported long distances, and wind dispersal dynamics depend on local and regional-level characteristics. For wind-dispersed plant species, lift-off potential is determined by the seed and maternal plant morphological attributes, while regional factors—such as physical landscape features and meteorological events—influence sustained flight. Despite the significant influence of wind patterns on seed dispersal, wind is rarely incorporated into landscape genetic analyses. We suggest a method to improve upon the current wind-dispersal models across a range of spatial scales using the species, Achyrachaena mollis (Asteraceae) as a study system. A. mollis is a range-limited, native annual that occurs throughout California and southern Oregon and is a suitable plant for a wind-dispersal study due to its seed morphology and reproductive attributes. The seeds have a pappus nearly twice as long as the achene, implying a strong dependence of seeds on wind-dispersal. Flowers are self-compatible and their flowering morphology suggests autogamous reproduction, ensuring any gene flow observed is from seed dispersal with minimal pollen dilution. Population-level genetic sampling of A. mollis was conducted throughout the Rouge River in southern Oregon. Preliminary analyses suggest this species experiences relatively frequent long-distance dispersal events. In particular, habitat quality (soil and climate variables) as well as development contribute to patterns in genetic diversity. We demonstrate local seed lift-off potential using morphological characteristics and modeling in a wind tunnel, model regional long-distance dispersal by characterizing wind turbulence over landscape surfaces, and validate the models using chloroplast and nuclear genetic markers to estimate dispersal within and among populations. To predict regional long-distance dispersal, we measure fluid behavior of land-use transitional zones in a wind tunnel including development, agriculture, and tree canopy. We interpolate wind patterns for the study range by assessing the instantaneous velocity field at each land-use intersection, resulting in a spatially-defined probability of long-distance dispersal.


1 - Portland State University, Biology, 1719 SW 10th Avenue, SRTC Rm 246, Portland, OR, 97201, United States
2 - Portland State University, Department Of Biology, 1719 SW 10th Ave, SRTC Rm 246 - Biology, Portland, OR, 97201, United States
3 - Portland State University, Department of Biology, 1719 SW 10th Avenue, SRTC Rm 246, Portland, OR, 97201, United States

Keywords:
anemochory
Asteraceae
Landscape genetics
morphology
wind modelling.

Presentation Type: Colloquium Presentations
Number: 0011
Abstract ID:276
Candidate for Awards:None


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