Journal of Tropical Ecology



Dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest in Thailand


Shumpei Kitamura a1c1, Shunsuke Suzuki a2, Takakazu Yumoto a1, Pilai Poonswad a3, Phitaya Chuailua a3, Kamol Plongmai a3, Naohiko Noma a2, Tamaki Maruhashi a4 and Chumphon Suckasam a5
a1 Center for Ecological Research, Kyoto University, Kamitanakami-Hirano, Otsu 520-2113, Japan
a2 School of Environmental Science, The University of Shiga Prefecture, Hikone 522-8533, Japan
a3 Hornbill Project, Department of Microbiology, Mahidol University, Bangkok 10400, Thailand
a4 Department of Human and Culture, Musashi University, Nerima, Tokyo 176-8534, Japan
a5 National Park, Wildlife and Plant Conservation Department, Bangkok 10900, Thailand

Article author query
kitamura s   [PubMed][Google Scholar] 
suzuki s   [PubMed][Google Scholar] 
yumoto t   [PubMed][Google Scholar] 
poonswad p   [PubMed][Google Scholar] 
chuailua p   [PubMed][Google Scholar] 
plongmai k   [PubMed][Google Scholar] 
noma n   [PubMed][Google Scholar] 
maruhashi t   [PubMed][Google Scholar] 
suckasam c   [PubMed][Google Scholar] 

Abstract

We investigated the seed dispersal of Aglaia spectabilis, a large-seeded tree species in a moist evergreen forest of Khao Yai National Park in Thailand. Although one-to-one relationships between frugivores and plants are very unlikely, large-seeded plants having to rely on few large frugivores and therefore on limited disperser assemblages, might be vulnerable to extinction. We assessed both the frugivore assemblages foraging on arillate seeds of Aglaia spectabilis and dispersing them and the seed predator assemblages, thereby covering dispersal as well as the post-dispersal aspects such as seed predation. Our results showed that frugivores dispersing seeds were a rather limited set of four hornbill and one pigeon species, whereas two squirrel species were not dispersers, but dropped the seeds on the ground. Three mammal species were identified as seed predators on the forest floor. Heavy seed predation by mammals together with high seed removal rates, short visiting times and regurgitation of intact seeds by mainly hornbills lead us to the conclusion that hornbills show high effectiveness in dispersal of this tree species.

(Accepted June 30 2003)


Key Words: caching; camera trapping; frugivore; frugivory; hornbills; rodents; scatter hoarding; seed dispersal; seed predation; squirrels.

Correspondence:
c1 Corresponding author. E-mail: shumpei@ecology.kyoto-u.ac.jp