Seasonality, dispersal modes, and optimal germination times modulate the fruiting of tropical tree species

Abstract

Abstract We investigated the associations of seasonality, dispersal modes and seed germination speeds with the fruiting of Clusia nemorosa, Pleroma fissinervium, and Vochysia pyramidalis in a gallery forest, Chapada Diamantina, Brazil. Observations of mature fruits with dispersing seeds were carried out from 2003 to 2006. Cross-correlation and circular statistics were performed to test the relationships among fruiting and abiotic factors, and phenological seasonality. Dispersion syndromes were defined and germination experiments were performed after seed collection (n =100/species), using four replicates. The species evidenced seasonal fruiting. Clusia nemorosa produced zoochoric seeds and V. pyramidalis anemochoric seeds, which were dispersed during the rainy season and positively correlated with precipitation; P. fissinervium produced autochoric seeds, released during the dry season to early rainy season, being positively correlated with insolation and negatively with humidity. The rotating wing seeds of V. pyramidalis were released in the rainy season and aided floating in watercourses, characterizing hydrochory. Clusia nemorosa and V. pyramidalis germinated (2-6 days) more rapidly than P. fissinervium (9 days). Seasonality, dispersal modes, and optimal germination conditions modulated the fruiting of the species examined, whose reproductive strategies responded to environmental drivers such as precipitation, favoring germination during the rainy season.