Annual variability in seed production by woody plants and the masting concept: reassessment of principles and relationship to pollination and seed dispersal

摘要

This article addresses a series of questions following the analysis of 296 published and unpublished data sets describing annual variation in seed output by 144 species of woody plants. Questions considered were: do plant species naturally fall intodistinct groups corresponding to masting and non-masting habits?; do plant populations generally exhibit significant bimodality in annual seed output?; and were there significant relationships between annual variability in seed production and pollination and seed dispersal modes? Distinct groups of species with contrasting levels of annual variability in seed output were not identified, but evidence that most polycarpic woody plants appear to adhere to alternating supra-annual schedules consisting of either high or low reproduction years was obtained. Seed production was slightly more variable among wind-pollinated taxa than animal-pollinated ones. Plants dispersed by mutualistic frugivores were less variable than those dispersed by either inanimate means or by animals which predominantly behaved as seed predators. The associations between supra-annual variability in seed output and pollination and seed dispersal methods suggested the existence of important reproductive correlates.