Spatial distributions are fundamental for sedentary organisms. Most work on plant spatial distributions has focused largely on spatial aggregation, while a handful of studies have suggested that median distance of individuals from the closest reproductive conspecific (establishment distance) may shift outward over time. This study empirically tested whether establishment distance shifts outward over time by comparing individuals of all sizes for five animal-dispersed tree species in Costa Rica. Whether positive distance-dependent survivorship drives such potential shifts in establishment distance was also tested. Invertebrate herbivory, light availability, and light heterogeneity were assessed as underlying mechanisms.

Establishment distance indeed shifted outward with increasing size classes for all but for one species, indicating eventual regeneration success only for seeds dispersed away. Such outward shifts resulted from positive distance-dependent survivorship, supporting the Janzen-Connell hypothesis, but only for the smallest size class. Such distance-dependent survivorship was not caused by herbivory or light availability, while light heterogeneity increased with distance from reproductive trees. These results reinforce the significance of seed dispersal and suggest that distance-dependent survivorship may drive some predictable plant spatiotemporal dynamics.