Please cite this article in press as: Kettle, C.J., et al., Determinants of fine-scale spatial genetic structure in three co-occurring rain forest canopy trees in Borneo. Perspect. Plant Ecol. Evol. Syst. (2010), doi:10.1016/j.ppees.2010.11.002 ARTICLE IN PRESS G Model PPEES-25112; No. of Pages 10 Perspectives in Plant Ecology, Evolution and Systematics xxx (2010) xxx–xxx Contents lists available at ScienceDirect Perspectives in Plant Ecology, Evolution and Systematics journal homepage: www.elsevier.de/ppees Research article Determinants of fine-scale spatial genetic structure in three co-occurring rain forest canopy trees in Borneo Chris J. Kettle a,∗ , Peter M. Hollingsworth c , David F.R.P. Burslem b , Colin R. Maycock b , Eyen Khoo d , Jaboury Ghazoul a a Ecosystem Management, Institute of Terrestrial Ecosystems, ETH Zurich, Universitaetstrasse 16, 8092 Zurich, Switzerland b Institute of Biological and Environmental Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK c Royal Botanic Gardens Edinburgh, 20a Inverleith Row, Edinburgh EH3 5LR, UK d Forest Research Centre, Sabah Forest Department, Sabah, Malaysia article info Article history: Received 8 March 2010 Received in revised form 26 October 2010 Accepted 10 November 2010 Keywords: Dipterocarpaceae Pollen dispersal Pollinator size Seed dispersal Flower size Microsatellites abstract Fine-scale spatial genetic structure (FSGS) within plant populations is an emergent property of the recruited adult trees, influenced by pollen and seed mediated gene flow, selection and demographic processes. This study aims to increase our understanding of the individual species traits that contribute to the generation of FSGS in the Dipteropcarpaceae, which is an ecologically and economically important family of tropical trees that dominate lowland forests in Southeast Asia. We examined FSGS in three co- occurring dipterocarp species at a single site in Borneo. Shorea xanthophylla, Parashorea tomentella and Dipterocarpus grandiflorus share limited seed dispersal but differ markedly in flower size, pollinator body size and pollen dispersal. Here we explore the role of pollen dispersal limitation in shaping FSGS in these three species. Using six microsatellite loci, we explore patterns of FSGS and landscape genetic structure and compare these across species. Significant FSGS was observed in S. xanthophylla and P. tomentella, both of which are known to have relatively limited pollen dispersal, but no clear signal of FSGS was observed in D. grandiflorus. Significantly greater FSGS was observed in P. tomentella (Sp = 0.012) than S. xanthophylla (Sp = 0.007) despite greater pollen dispersal in P. tomentella. Bayesian clustering analysis revealed sig- nificant structure in P. tomentella at the scale of the forest reserve (4000 ha). We discuss the alternative explanations for the observed patterns of FSGS emphasising the complexity of the mechanisms that can generate FSGS in long-lived trees. The extent of species-specific pollen dispersal is one factor that can contribute to differences in FSGS across species, but is not the only determinant. The observed patterns of FSGS and landscape scale genetic structure in S. xanthophylla and P. tomentella illustrate the potential of gap regeneration to counter act pollen dispersal and contribute to increased aggregation of related individuals (FSGS). © 2010 Elsevier GmbH. All rights reserved. Introduction Forest tree species typically have high intra-population genetic diversity attributed to their large long-term effective population size and extensive gene dispersal (Hamrick, 2004; Petit and Hampe, 2006). The intensity of fine-scale spatial genetic structure (FSGS) in continuous populations is expected to be greatest in those species with the most restricted pollen and seed dispersal (Vekemans and Hardy, 2004). Theoretical and empirical studies indicate that lim- ited pollen dispersal is a strong candidate for generating FSGS within populations of plant species that exhibit limited seed dis- ∗ Corresponding author. Tel.: +41 44 632 31 95; fax: +41 44 632 15 75. E-mail address: chris.kettle@env.ethz.ch (C.J. Kettle). persal (Hardy et al., 2006). Other factors such as successional status (Chung et al., 2007), population density (Vekemans and Hardy, 2004) and regeneration mode (Premoli and Kitzberger, 2005) are also important. Several studies of tropical forest tree species have provided insights into species traits that influence their population and evolutionary dynamics including FSGS (Born et al., 2008; Jones and Hubbell, 2006), and others have undertaken meta-analyses to search for general patterns between reproductive traits and FSGS (Dick et al., 2008; Hardy et al., 2006). Teasing apart the way species traits influence FSGS is, however, difficult because there are often multiple and different variables between studies or species (Hardy et al., 2006). Knowledge of the drivers of FSGS in tropical tree species is important as it can inform conservation and management strate- 1433-8319/$ – see front matter © 2010 Elsevier GmbH. All rights reserved. doi:10.1016/j.ppees.2010.11.002