Summary
In Guyana, we examined temporal variability and ecological consequences of seedbased reproduction in the ectomycorrhizal, monodominant leguminous canopy tree Dicymbe corymbosa using an extensive 2003–2017 dataset encompassing two masting events. Annual seed output, predation and nutrient investment were recorded in primary D. corymbosa forests. Seedling establishment, survival and growth were monitored. Mast seeding occurred in 2003 and 2016 and low seeding events occurred every 3–4 years, separated by non-reproductive years. In accordance with predicted climatic entrainment of regional masting, El Niño-intensified dry seasons preceded each masting event but not low seeding events. The regularly variable seeding pattern by D. corymbosa suggests that innate supra-annual periodicity may initiate D. corymbosa flowering. Internal resource thresholds may also contribute to periodicity, but El Niño-associated intensified dry seasons appear necessary to entrain mass flowering and successful mast seeding across the region. In accordance with a predator satiation hypothesis, seed predation was proportionally higher during low seed years. Competitive gains from the 2016 masting event were evidenced by strong replenishment of declining seedling pools.
Reference
Henkel TW, Mayor JR. 2019. Implications of a long-term mast seeding cycle for climatic entrainment, seedling establishment, and persistent monodominance in a Neotropical, ectomycorrhizal canopy tree. Ecological Research 34: 472-484.