DOI: 10.5061/dryad.cjsxksn1r
title: Highlighting convergent evolution in morphological traits in response to climatic gradient in African tropical tree species: the case of genus Guibourtia Benn

description: Adaptive evolution is a major driver of organism diversification but the
 links between phenotypic traits and environmental niche remains little
 documented in tropical trees. Moreover, trait-niche relationships are
 complex because a correlation between the traits and environmental niches
 displayed by a sample of species may result from (1) convergent evolution
 if different environmental conditions have selected different sets of
 traits, and/or (2) phylogenetic inertia if niche and morphological
 differences between species are simply function of their phylogenetic
 divergence, in which case the trait-niche correlation does not imply any
 direct causal link. Here, we aim to assess the respective roles of
 phylogenetic inertia and convergent evolution in shaping the differences
 of botanical traits and environmental niches among congeneric African tree
 species that evolved in different biomes. This issue was addressed with
 the tree genus Guibourtia Benn. (Leguminosae, Detarioideae) which contains
 13 African species occupying various forest habitat types, from rain
 forest to dry woodlands, with different climate and soil conditions. To
 this end, we combined morphological data with ecological niche modelling
 and used a highly resolved plastid phylogeny of the 13 African Guibourtia
 species. First, we demonstrated phylogenetic signals in both morphological
 traits (Mantel test between phylogenetic and morphological distances
 between species: r=0.24, p=0.031) and environmental niches (Mantel test
 between phylogenetic and niche distances between species: r=0.23,
 p=0.025). Second, we found a significant correlation between morphology
 and niche, at least between some of their respective dimensions (Mantel’s
 r=0.32, p=0.013), even after accounting for phylogenetic inertia
 (Phylogenetic Independent Contrast: r=0.69, p=0.018). This correlation
 occurred between some leaflet and flower traits and solar radiation,
 relative humidity, precipitations and temperature range. Our results
 demonstrate the convergent evolution of some morphological traits in
 response to climatic factors in congeneric tree species and highlight the
 action of selective forces, along with neutral ones, in shaping the
 divergence between congeneric tropical plants.
description: <strong>Information contained in the attached files</strong> <strong>det.img - etp.img - PH1.img - prc.img - rhu.img - shr.img - temp.img - wnd.img :</strong> Climate (temperature range (°C); Potential evapotranspiration (mm); precipitation (mm); relative humidity (%); solar radiation (w/m<sup>2</sup>); temperature (°C) and wind speed (m/s)) and soil (pH) data were extracted from the Climatic Research Unit (CRU) of the University of East Anglia (New et al., 1999; Mitchell and Jones, 2005) and “FAO Digital Soil Map of the World, version 3.6” <strong>guibourtia_data_401_sp.txt :</strong> occurrence points of the 13 <i>Guibourtia</i> species were used to model the species environmental niches. <strong>data_morpho.xls : </strong>morphological database used in this paper. A total of 281 georeferenced herbarium samples were used for the morphological analyses <strong>Env_281_data.txt:</strong> geographical coordinate and climate and soil data for each herbarium samples