DOI: 10.5061/dryad.s3k04
title: Data from: Evidence for ecological divergence across a mosaic of soil types in an Amazonian tropical tree: Protium subserratum (Burseraceae)

description: Soil gradients are known to be an important driver of divergent natural
 selection in plant populations. Neotropical trees have the highest
 diversity on earth and it is not uncommon to find soil specialist
 congeners distributed parapatrically. Nevertheless very little is known
 about the role that edaphic heterogeneity plays in the origin and
 maintenance of tropical tree diversity. We predict that the mosaic of
 different soils in the lowland Amazon rainforest play a major role in
 generating and maintaining genetic variation in tropical tree populations
 through ecological divergence. This study examines genetic and
 morphological differentiation in the tropical tree Protium subserratum
 populations growing on the mosaic of white-sand, brown-sand and clay soil
 types distributed parapatrically throughout the western Amazon basin. We
 use nuclear microsatellites and vegetative characters to answer four major
 questions: (1) Are populations phenotypically and genetically
 differentiated across all three habitat types? (2) Can we detect a
 signature of natural selection over drift divergence among populations on
 different soil types? (3) What is the extent of hybridization and
 introgression across habitat types? (4) What is the relative importance of
 spatial distance and soil type in structuring P. subserratum tree
 populations and influencing migration rates among populations? We found
 significant morphological variation in populations across the three soil
 types. Higher levels of genetic differentiation and lower levels of gene
 flow were observed between adjacent populations found on different soil
 types than between geographically distant populations on the same soil
 type. Comparisons of phenotypic and neutral genetic variation among soil
 specialist populations suggest a role for natural selection in population
 divergence and a small number of hybrid individuals were detected between
 soil ecotypes showing that gene flow among populations may be occurring at
 a low frequency. Our results suggest that edaphic specialization in P.
 subserratum populations has occurred across multiple soil boundaries.
 While we cannot discern which factors caused initial divergence our
 results do suggest that natural selection is plays an important role in
 maintaining the integrity of populations across ecological boundaries and
 that edaphic specialization may be a general mechanism that promotes and
 maintains Amazonian tree diversity.
description: Raw_msat_genealexinputRaw microsatellite data formatted for Gen Al Ex.locality data for final data setUTM coordinates and population data for all individuals genotyped in this study.Structure_inputInput file for use in STRUCTUREStructureinput.txtBS-B_ClayB_newhybridinputInput file for program NewHybrid for analysis of hybridization between pops. BS-B and Clay-BBS-A_WS-A_newhybridinputInput file for program NewHybrid for comparison of populations BS-A and WS-AMigrate-N input fileInput file for Migrate-N which includes all populations and all loci.Morphology_datasetAll morphological measurements used