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Consequences of time of fruit production for secondary dispersal and establishment of three palm species.
VILLEGAS, ANA*,1, NOTMAN, EVAN2, 1 Organization for Tropical Studies, San Jose, Costa Rica2 Organization for Tropical Studies, San Jose, Costa Rica
ABSTRACT- We investigated the consequence of seed production during different seasons on germination and survival of seeds for three species of palms in lowland forest of Costa Rica. We documented patterns of germination and seed survival during periods with different rainfall and community fruiting. Specifically, how timing of fruit production influenced; (1) time to germination (2) post-dispersal seed mortality (3) secondary dispersal by vertebrates (4) relative importance of different mortality sources (pathogens, invertebrate, and vertebrate). Seeds of Welfia regia, Socratea exorrhiza, and Iriartea deltoide were placed individually along transects in four replicate plots and in two treatments (1) protected from vertebrates (2) unprotected, but attached to a thread to follow seed movement. Fresh seeds of W. regia, were put out in February, May, August, and November 2001. Seeds of S. exorrhiza and I. deltoide were put out in three and two of these periods respectively. Levels of seed movement differed between species, but not between seasons. Survival of seeds protected from vertebrates was greater for all species and differed between species but not season. Survival of unprotected seeds differed between species and season. Time of germination differed between season for W. regia and I. deltoide. Seed survival was higher during the period of community wide fruit scarcity. Differences in survival between seasons appear to be due to how vertebrates treat seeds (consumed or cached) and not to vertebrate abundance.
KEY WORDS: dispersal, phenology, predation, seed