DISTANCE AND NONRANDOMNESS OF SEED DISPERSAL BY THE DWARF CASSOWARY CASUARIUS-BENNETTI

To determine the sources of dispersed seeds I inserted unique tags in fallen Aglaia aff. flavida seeds before dwarf cassowaries (Casuarius b ennetti) ate the fruits containing the seeds. Thirty naturally-dispers itd. marked seeds were re-located in cassowary droppings in a 100 ha s tudy area. The distribution of seed dispersal distances did not differ significantly from a normal distribution with a mean dispersal distan ce of 388 m, SD=196.8. Mean distance of dispersed seeds to nearest mat ure conspecific tree was 170 m, SD=108.4: dispersed seeds usually land ed closer to other conspecifics than their parent. The estimated distr ibution of all seeds (including many undispersed seeds) was leptokurti c, creating high densities near source trees (>0.035 seeds m(-2) withi n 100 m of bole) that quickly tapered off (<0.002 seeds m(-2) >100 m f rom the bole); any density dependent effects are liable to be manifest only near parent trees. Cassowary movement patterns and resting behav ior caused non-random dispersal of seeds. Seeds were preferentially mo ved to level sites uphill from their source trees along routes that di d not cross steep terrain, Undispersed seeds generally landed downhill from source trees. This population of Aglaia would probably contract downhill into smaller, fragmented populations in the absence of cassow ary-mediated dispersal.