A TEST OF THE JANZEN-CONNELL MODEL WITH 2 COMMON TREE SPECIES IN AMAZONIAN FOREST

Field experiments and survival analysis were used to test whether the Janzen-Connell model operated for two common Amazonian tree species in Peru: the midstorey palm, Astrocaryum murumuru, and the canopy-emerge nt legume, Dipteryx micrantha. Seed and seedling survival patterns of these species partially supported the model, depending on tree species , type of predator, spatial scale and the particular year. At a small scale of a 2.5-ha plot, Astrocaryum seed predation by insects and mamm als was density-dependent. At a larger scale of 100 ha, Dipteryx seed survival increased with distance from conspecific adults, but for Astr ocaryum seeds there was no distance dependence. At the scale of 200-40 0 ha Dipteryx seed survival was negatively related to the number of in dividuals present in groups of conspecific adult trees. In 1992 a high er proportion of Astrocaryum seedlings survived far from, compared wit h close to, conspecific adult trees, whilst in 1993 more Dipteryx seed lings survived beneath conspecific adult trees than farther away.