Post-dispersal seed predation on eleven large-seeded species from the New Zealand flora: a preliminary study in secondary forest.
Seed predation trials were conducted for 11 large-seeded species native to New Zealand in secondary forest. The species used were: Alectryon excelsus, Beilschmiedia tawa, Coprosma grandifolia, Corynocarpus laevigatus, Hedycarya arborea, Myoporum laetum, Nestegis cunninghamii, Prumnopitys ferruginea, Prumnopitys taxifolia, Rhopalostylis sapida and Ripogonum scandens. Seed removal was monitored for 15 days for 160 seeds of each species, placed in piles of 5 seeds in each of 4 treatments (open ground, open pot, pot with coarse mesh to exclude larger vertebrates, and pot with predator-proof mesh to exclude all mammals) at each of 8 sites in the Karori Wildlife Sanctuary, Wellington, in 1998. Removal of depulped seeds from treatments to which all species had access ranged from 3.8 to 23.8%, with a mean of 9.8%. No seeds were removed from the treatment that excluded all vertebrates. Presence of flesh on the seeds significantly increased seed removal rates in the 3 species tested with and without flesh. No relationship was found between seed removal and seed size, seed mass, or the proportion of the seed mass that was contributed by the seed coat. The seed removal rates reported here are exceptionally low, and suggest that the potential for post-dispersal seed predation to limit regeneration of native forest in New Zealand may have been overestimated, at least in the forest type studied.