title: The gravity of pollination: integrating at-site features into spatial analysis of contemporary pollen movement.
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.
authors.affiliation: Department of Biology, University of Toronto, Mississauga, ON, L5L 1C6, Canada.
authors.forename: Michelle F
authors.initials: MF
authors.lastname: DiLeo
authors.forename: Jenna C
authors.initials: JC
authors.lastname: Siu
authors.forename: Matthew K
authors.initials: MK
authors.lastname: Rhodes
authors.forename: Adriana
authors.initials: A
authors.lastname: López-Villalobos
authors.forename: Angela
authors.initials: A
authors.lastname: Redwine
authors.forename: Kelly
authors.initials: K
authors.lastname: Ksiazek
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Dyer
mesh_terms: D029768:Cornus / Q000235:genetics / Q000502:physiology; D017753:Ecosystem; D051456:Gene Flow; D014644:Genetic Variation; D005828:Genetics, Population; D006112:Gravitation; D008957:Models, Genetic; D011058:Pollen / Q000235:genetics; D054817:Pollination; D012044:Regression Analysis; D062206:Spatial Analysis; D014197:Trees / Q000235:genetics / Q000502:physiology
keywords: Cornus florida; gene flow; gravity models; landscape genetics; population graphs