The gravity of pollination: integrating at-site features into spatial analysis of contemporary pollen movement

MOLECULAR ECOLOGY. 2014.

cornus florida
gene flow
gravity models
landscape genetics
population graphs
Authors
Affiliation

Michelle F. Dileo

Jenna C. Siu

Matthew K. Rhodes

Adriana Lopez-Villalobos

Angela Redwine

Kelly Ksiazek

Center for Environmental Studies

Published

August 1, 2014

Doi

PDF Download DOI 10.1111/mec.12839

Abstract

Pollen-mediated gene flow is a major driver of spatial genetic structure in plant populations. Both individual plant characteristics and site-specific features of the landscape can modify the perceived attractiveness of plants to their pollinators and thus play an important role in shaping spatial genetic variation. Most studies of landscape-level genetic connectivity in plants have focused on the effects of interindividual distance using spatial and increasingly ecological separation, yet have not incorporated individual plant characteristics or other at-site ecological variables. Using spatially explicit simulations, we first tested the extent to which the inclusion of at-site variables influencing local pollination success improved the statistical characterization of genetic connectivity based upon examination of pollen pool genetic structure. The addition of at-site characteristics provided better models than those that only considered interindividual spatial distance (e.g. IBD). Models parameterized using conditional genetic covariance (e.g. population graphs) also outperformed those assuming panmixia. In a natural population of Cornus florida L. (Cornaceae), we showed that the addition of at-site characteristics (clumping of primary canopy opening above each maternal tree and maternal tree floral output) provided significantly better models describing gene flow than models including only between-site spatial (IBD) and ecological (isolation by resistance) variables. Overall, our results show that including interindividual and local ecological variation greatly aids in characterizing landscape-level measures of contemporary gene flow.