Community seed rain patterns and a comparison to adult community structure in a West African tropical forest

We examined the seed rain throughout a twelve month period in a lowland tropical forest in Cameroon, West Africa, 1996-97. Traps (0.5 m(2), n = 216) were erected throughout a 25 km(2) area in 24 randomly placed clusters of nine traps each. Fruits and seeds that landed in traps were collected every 7- 10 days and classified by species and dispersal type. More than 32,000 seeds from approximately 200 species fell into the traps, an average of 297 seeds m(-2) yr(-1) Thirty species represent 82% of the total seed rain while an additional 175 species comprise the remaining 18%. When we compared the adult community to the seed rain community within the same plots, we found no apparent correlation between seed rain patterns and adult community structure for this year of study. Furthermore, only 49% of the adult tree community produced and dispersed seed into traps in this year. More than 100 species (52%) found in the seed rain represented long-distance immigrant seed rain. Seed rain was highly variable at several scales, both spatially and seasonally, although seeds arrived in traps during each collection period. Cluster analyses showed that traps within plots were seldom more similar to one another than traps between plots. While 82% of the tree species in the community are thought to be animal dispersed, only 28% of all seeds that fell into traps had been obviously "handled" (bitten, chewed, or passed) by animals. Tests for fruit and seed removal by predators or dispersers found 5% or less removal rate from traps.