par Liu, Jasmine 
Promoteur Hardy, Olivier J.
Co-Promoteur Bauman, David
Publication Non publié, 2022-08-30
Promoteur Hardy, Olivier J.
Co-Promoteur Bauman, David
Publication Non publié, 2022-08-30
Mémoire
| Résumé : | Many mechanisms of coexistence have been proposed to explain high tree species diversity in tropical forests. Neighborhood interactions, through competition for resources and natural enemies, is a crucial driver of diversity. Demography – how trees grow, survive, and reproduce – is one of the most direct ways to assess fitness differences under variable conditions, such as topographic habitat and characteristics of neighborhood interactions like crowding and neighbor species identity. However, integration of phylogenetic information into studies of tree performance response to neighborhood interactions is seldom done for high diversity communities beyond limited species subsets.Here, we aim to understand and quantify the effects of neighborhood crowding and phylogenetic relatedness on tree growth dynamics in an African tropical moist forest. We use spatially explicit Bayesian models of growth over a decade at the community and species levels for >170,000 individuals of 271 species in a 50-ha plot in Cameroon.Across species, tree growth is suppressed by increased crowding, but the effect is mediated by phylogenetic relatedness of the surrounding neighborhood, with high relatedness exacerbating crowding’s effect on growth. Furthermore, the effect of neighborhood relatedness on growth is largely driven by conspecifics. We additionally find high variability in species-specific sensitivity to crowding; specifically, sensitivity increases strongly with mean species growth rate. Taken together, this study highlights the importance of neighborhood interactions in community dynamics. The high interspecific variation in sensitivity to crowding and strong trade-off between species growth rate and sensitivity contributes to a more complete understanding of coexistence in high diversity tree communities. |
