Effects of Bird Ingestion on Seed Dispersal and Germination of the Elaeagnm macrophylla

摘要

ab:The Elaeagnus macrophylla is a stenoecious evergreen plant with nitrogen-fixing symbjonts and its timing of fruit-ripening coincides with spring migration of many birds in southwestern Korea. To recognize bird species which eat fleshy fruits of theElaeagnus macrophylla and to evaluate the erfects of bird ingestion on seed germination and dispersal, we monitored birds and carried out germination experiments using its fruits and seeds from March to April 2007 at Hongdo Island, Jeonnam Province, Korea. As a result, eight species of birds including the Gray Starling (Sturnus cineraceus), the Brown-eared Bulbul (Hypsipetes amaurotis) and the Dusky Thrush (Turdus naumanni) ingested the fruits. Germination rate was enhanced but length of seed dormancywas instead shortened in ingested (collected from the feces of birds) and manually extracted seeds (obtained directly from the fruits) than in intact fruits collected directly from the plant. Moreover, the possible scale of seed dispersal by the frugivorous birds ranged up to 6.9 ha based on home ranges of starlings. Consequently, the Elaeagnus macrophylla supplies food resources for migratory birds, and the birds give the plant opportunities of new colonization. We suggest that this kind of interactionbetween the nitrogen-fixing plant and avian seed dispersers is applicable as a process of natural restoration in degraded coastal evergreen forests.