Small seed selects for mast seeding in perennial plants

Aim: Reproduction in perennial plants varies from relatively constant among years to production of massive and synchronous seed crops at irregular intervals, a reproductive strategy called mast seeding. The sources of that interspecific differences in the extent of interannual variation in seed production are largely unknown. 

Location: Interannual variation in seed production of 340 plant species located world-wide.

Methods: We conducted a global meta-analysis of 340 animal-dispersed species to quantify how the interannual variability of seed crops of plants can be explained by seed mass, dispersal mode, phylogeny and climate. 

Results: Phylogenetic analysis indicated that interannual variation in seed production and seed mass tend to be similar in related species owing to their shared evolutionary. Interannual variation in seed production was 1.22 times higher in synzoochorous compared to endozoochorous species. Moreover, production of small seeds was associated with higher interannual variation in seed production although synzoochorous species produce larger seeds than endozoochorous species. Precipitation rather than temperature showed significant positive effect on interannual variation in seed production. Seed mass and dispersal mode contribute more to interannual variation in seed production than phylogeny, climate and fruit type. 

Main conclusion: Our study lends support to a long-standing notion that interspecific variation in masting intensity is largely shaped by the interactions of plants with animals. Masting is avoided when interannual variation in seed production can harm mutualists and promoted when satiation can decrease predation and increase seed dispersal.