Please use this identifier to cite or link to this item: http://hdl.handle.net/10790/5379

Seed Dispersal & Germination by Native vs. Exotic Avian Frugivores of Hawaiʻi Island

File Size Format  
Matsuoka_hilo.hawaii_1418O_10194.pdf 10.38 MB Adobe PDF View/Open

Item Summary

Title:Seed Dispersal & Germination by Native vs. Exotic Avian Frugivores of Hawaiʻi Island
Authors:Matsuoka, Koa
Contributors:Ostertag, Rebecca (advisor)
Tropical Conservation Biology & Environmental Science (department)
Keywords:Environmental science
Biology
extinction
forest birds
reintroductions
show 2 morerestoration
seed dispersal
show less
Date Issued:Jun 2020
Publisher:University of Hawaii at Hilo
Abstract:On islands worldwide, mass avian extinctions related to anthropogenic activity have enabled exotic generalists to fill empty niches left by larger native specialists. In Hawaiʻi, this trend is prevalent; therefore, ensuring the survival Hawaiʻi’s last few native frugivores, the ʻalalā (Corvus hawaiiensis) and ʻōmaʻo (Myadestes obscurus), is integral in preserving proper seed dispersal function. Recently proposed management actions include reintroducing native frugivores into former ranges on leeward Hawaiʻi Island. This study sought to determine which native fruiting plants would benefit from native frugivore reintroductions and how exotic frugivores compare to natives in seed dispersal efficacy. I measured and compared the diet composition of two non-native, warbling white-eye (Zosterops japonicus) and red-billed leiothrix (Leiothrix lutea), and two native (ʻōmaʻo and ʻalalā) bird species. I also compared germination success of nine native fruiting plants consumed by these species. To examine diet composition and germination, I collected seeds from avian fecal samples and planted them in growth media to detect differences in gut-passage effects on germination percent and rate among avian species. I also collected avian seed rain using aerial seed traps hung above the fruiting understory to determine if avian diet and seed rain were similar in composition. ʻŌmaʻo had significantly higher diet diversity than other frugivores. Leiothrix and ʻalalā had similar but lower diversity, and warbling white-eye had the lowest diet diversity and were the least frugivorous. For germination success, the key influence was pulp-removal, by bird or hand, as there were no conclusive differences between avian gut-passage in birds and control seeds without pulp. Results showed a proportional representation of different fruits in bird diet matched that in seed rain. These results support ‘ōmaʻo and ʻalalā reintroductions as a strategy to promote dispersal of native plants and provide insight into potential changes in the native plant community composition should native frugivores go extinct and be supplanted by exotics.
Pages/Duration:55 pages
URI:http://hdl.handle.net/10790/5379
Rights:All UHH dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: Tropical Conservation Biology and Environmental Science
TCBES Theses


Please email libraryada-l@lists.hawaii.edu if you need this content in ADA-compliant format.

Items in UH System Repository are protected by copyright, with all rights reserved, unless otherwise indicated.