title: Positive density-dependent reproduction regulated by local kinship and size in an understorey tropical tree.
abstract: OBJECTIVE
  Global pollinator declines and continued habitat fragmentation highlight the critical need to understand reproduction and gene flow across plant populations. Plant size, conspecific density and local kinship (i.e. neighbourhood genetic relatedness) have been proposed as important mechanisms influencing the reproductive success of flowering plants, but have rarely been simultaneously investigated.
  
  
  METHODS
  We conducted this study on a continuous population of the understorey tree Miconia affinis in the Forest Dynamics Plot on Barro Colorado Island in central Panama. We used spatial, reproductive and population genetic data to investigate the effects of tree size, conspecific neighbourhood density and local kinship on maternal and paternal reproductive success. We used a Bayesian framework to simultaneously model the effects of our explanatory variables on the mean and variance of maternal viable seed set and siring success.
  
  
  RESULTS
  Our results reveal that large trees had lower proportions of viable seeds in their fruits but sired more seeds. We documented differential effects of neighbourhood density and local kinship on both maternal and paternal reproductive components. Trees in more dense neighbourhoods produced on average more viable seeds, although this positive density effect was influenced by variance-inflation with increasing local kinship. Neighbourhood density did not have significant effects on siring success.
  
  
  CONCLUSIONS
  This study is one of the first to reveal an interaction among tree size, conspecific density and local kinship as critical factors differentially influencing maternal and paternal reproductive success. We show that both maternal and paternal reproductive success should be evaluated to determine the population-level and individual traits most essential for plant reproduction. In addition to conserving large trees, we suggest the inclusion of small trees and the conservation of dense patches with low kinship as potential strategies for strengthening the reproductive status of tropical trees.
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, 1 University Station, Biological Laboratories C0930, Austin, TX 78712, USA.
authors.forename: Antonio R
authors.initials: AR
authors.lastname: Castilla
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, 1 University Station, Biological Laboratories C0930, Austin, TX 78712, USA.
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Pope
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, 1 University Station, Biological Laboratories C0930, Austin, TX 78712, USA sjha@austin.utexas.edu.
authors.forename: Shalene
authors.initials: S
authors.lastname: Jha
mesh_terms: D001499:Bayes Theorem; D017753:Ecosystem; D005828:Genetics, Population; D019684:Magnoliopsida / Q000033:anatomy & histology / Q000502:physiology*; D018895:Microsatellite Repeats; D010176:Panama; D012098:Reproduction / Q000502:physiology*; D012639:Seeds / Q000235:genetics / Q000502:physiology; D014197:Trees; D014329:Tropical Climate
keywords: local kinship; positive density dependence; seed abortion; siring success; spatial genetic structure, tropical tree