Density-dependent reproductive success among sympatric dipterocarps during a major mast fruiting event

Background

Masting or mast fruiting is the annual synchronous production of many seeds by a plant species. Masting is an important reproductive strategy that depends on the intensity of flowering and fruiting, as well as the seeds’ ability to survive herbivory and competition with other seeds. Southeast Asia, many tree species (particularly Dipterocarps) are known to synchronize their masting events and therefore, community-wide seed density is an important factor predicting successful reproduction.

Goals and Methods

In the Deramakot and Tangkulap Forest Reserves of Sabah, Malaysia, the authors use seed traps to capture the seeds. Species, site, treatment and species interaction are evaluated for their influence on survival of dispersed seeds. Across all sites is a range of tree density, distance to forest edge, and competing understory species. Tree species, weight, and number of seeds is recorded. In addition, the authors record seed condition which notes signs of maturity, sterility, and herbivory.

Conclusions and Takeaways

The authors report that rarer species produce more mature seeds, but both abundant and rare species had high survival rates. Less abundant species synchronize their masting events with more abundant species to achieve greater reproductive success. It is noted that tree species in earlier life stages have a higher seed production and survival rate than older trees, and a higher density of older trees negatively impacts seed survival in dipterocarps.