Recruitment, a multi-stage process with unpredictable result: the case of a Sapotaceasae in French Guianan forest

The net result of the multi-stage recruitment from seed production to seedl ing establishment was assessed along 3 consecutive years in Chrysophyllum l ucentifolium (Sapotaceae) in a mature rain forest of French Guiana. Accordi ng to year, between 37 and 42 % of seed production was primarily dispersed away from fruiting trees without damage, especially by primates. Seeds disp ersed in howler monkeys' (Alouatta seniculus) defecation were serendipitous ly buried by dung beetles (14%), eaten by terrestrial vertebrates such as r odents, or destroyed by insects or pathogens. The proportion of seeds secon darily dispersed by scatterhoarding rodents Varied from 3 to 17 % according to year. The survival rate of unremoved and uneaten seeds after 20 days, v aried from 2 to 56 % according to year and pattern of spatial distribution generated by primary dispersal (clump or scattered). The empirical model ba sed on the seed and seedling fate diagram showed that, according to years, from 6 to 15 % of produced seeds lead to seedling establishment away from p arent tree. Variations in patterns of seed removal and predation by rodents were the most crucial factors governing the effectiveness of primary and s econdary dispersers and the spatial distribution of seedlings. Between-year variations of recruitment were important and stochastic because the fluctu ations of seed production and seed dispersal/predation varied independently . The proposed empirical model has thus no predictive value. However it can be useful for instance to test the effects of seed size and of some faunal perturbations.