Seed and pollen dispersal plays a crucial role in species persistence by shaping populations on a large scale. However, empirical studies linking small-scale dispersal to large-scale patterns are scarce. We analysed the reproductive ecology of Staudtia kamerunensis (Myristicaceae), a tree species widespread in Central Africa, with the aim of linking its reproductive ecology to its large-scale population dynamics, characterised by a range expansion in the Congo Basin. We investigated gene flow and dispersal using parentage analyses and fine-scale spatial genetic structure in two landscape types, a closed-canopy forest and a forest-savanna mosaic. We found a deficit in regeneration despite fair seed production in the closed-canopy forest. Staudtia kamerunensis is a self-compatible monoecious species (8% selfed progeny), although the decay of inbreeding with age highlights inbreeding depression. Pollen dispersal (dp = 580 m) was more extensive than seed dispersal in the closed-canopy forest, where we detected a significant fine-scale spatial genetic structure (Sp = 0.0083), while gene flow was more extensive in the fragmented forest. The median diameter for reproduction was dbh50 = 58 cm whereas trees reproduce efficiently from 40 cm. This study provides insight into the reproductive ecology and dispersal of S. kamerunensis, revealing patterns that are consistent with previous studies on its population dynamics. Our results also provide insights to maintain healthy populations. We recommend a minimum cutting diameter of 60 cm or regulation to maintain at least 50% of the original reproductive potential after logging operation to preserve the reproductive potential of natural populations.

Epiphytic communities live in a unique, three-dimensional micro-habitat space that offers an original framework to disentangle the contribution of environmental filters, biotic interactions and dispersal limitation to community structure at small spatial scales. We took advantage of a tropical canopy crane facility to record and model spatio-temporal microclimatic variation and assess its impact on the composition and phylogenetic structure of epiphytic bryophyte communities. Generalized Dissimilarity Modelling evidenced the crucial role of microclimates in determining the composition of moss and liverwort communities. The shift between negative or non-significant phylogenetic turnover to consistently significant clustering from the base to the canopy suggests that phylogenetic constraints further contribute to shape the assembly of epiphytic bryophyte communities. The slight, but significant correlation between increasing phylogenetic clustering with variation in microclimatic conditions adds to emerging evidence for the role of environmental filtering upon community assembly, including at the small spatial scales of epiphytic communities.