TY - JOUR T1 - Geological Substrates Shape Tree Species and Trait Distributions in African Moist Forests A1 - Fayolle, Adeline A1 - Engelbrecht, Bettina A1 - Freycon, Vincent A1 - Mortier, Frédéric A1 - Swaine, Michael A1 - Réjou-Méchain, Maxime A1 - Doucet, Jean-Louis A1 - Fauvet, Nicolas A1 - Cornu, Guillaume A1 - Gourlet-Fleury, Sylvie Y1 - 2012/08/15 N2 - Background Understanding the factors that shape the distribution of tropical tree species at large scales is a central issue in ecology, conservation and forest management. The aims of this study were to (i) assess the importance of environmental factors relative to historical factors for tree species distributions in the semi-evergreen forests of the northern Congo basin; and to (ii) identify potential mechanisms explaining distribution patterns through a trait-based approach. Methodology/Principal Findings We analyzed the distribution patterns of 31 common tree species in an area of more than 700,000 km2 spanning the borders of Cameroon, the Central African Republic, and the Republic of Congo using forest inventory data from 56,445 0.5-ha plots. Spatial variation of environmental (climate, topography and geology) and historical factors (human disturbance) were quantified from maps and satellite records. Four key functional traits (leaf phenology, shade tolerance, wood density, and maximum growth rate) were extracted from the literature. The geological substrate was of major importance for the distribution of the focal species, while climate and past human disturbances had a significant but lesser impact. Species distribution patterns were significantly related to functional traits. Species associated with sandy soils typical of sandstone and alluvium were characterized by slow growth rates, shade tolerance, evergreen leaves, and high wood density, traits allowing persistence on resource-poor soils. In contrast, fast-growing pioneer species rarely occurred on sandy soils, except for Lophira alata. Conclusions/Significance The results indicate strong environmental filtering due to differential soil resource availability across geological substrates. Additionally, long-term human disturbances in resource-rich areas may have accentuated the observed patterns of species and trait distributions. Trait differences across geological substrates imply pronounced differences in population and ecosystem processes, and call for different conservation and management strategies. JF - PLOS ONE JA - PLOS ONE VL - 7 IS - 8 UR - https://doi.org/10.1371/journal.pone.0042381 SP - e42381 EP - PB - Public Library of Science M3 - doi:10.1371/journal.pone.0042381 ER -