How to translate text using browser tools
1 July 1998 Influence of Seed Processing by Frugivorous Birds on Germination Success of Three North American Shrubs
Gretchen A. Meyer, Mark C. Witmer
Author Affiliations +

Coevolutionary models of the interactions between fruiting plants and avian seed dispersers have been influenced by the assumption that regurgitation and defecation of seeds have diffferent effects on seed coats, and consequently seed germination. We evaluated how the manner of seed processing affects seed germination by feeding fruits of three bird-dispersed shrubs, spicebush (Lindera benzoin), chokecherry (Prunus virginiana), and arrowwood (Viburnum dentatum), to captive cedar waxwings (Bombycilla cedrorum) and thrushes (Turdus migratorius, Hylocichla mustelina, Catharus guttatus and C. minimus). Cedar waxwings defecate all seeds, whereas thrushes regurgitate most seeds. For all three shrub species and all five bird species, there were no differences in germination success between seeds manually cleaned of pulp, and cleaned, bird-passed seeds, regardless of whether seeds were regurgitated or defecated. However, seeds of Lindera and Prunus that were defecated by cedar waxwings and planted with feces, mimicking the depositional environment of defecated seeds in nature, suffered reduced germination relative to cleaned seeds. Thus, our results do not suggest that whether seeds are regurgitated or defecated is an important component of dispersal quality because of direct effects on the seed coat. Instead, seed processing modes differed in their effects on seed germination because of the feces associated with defecated seeds. Removal of fruit pulp from seeds by frugivores, a fundamental consequence of dispersal in animal guts, was critical for germination, especially for seeds within the lipid-rich fruits of Lindera and Viburnum. This suggests that for some fruiting plants, frugivores provide an essential service by freeing seeds from fruit pulp, in addition to their role in seed dispersal.

Gretchen A. Meyer and Mark C. Witmer "Influence of Seed Processing by Frugivorous Birds on Germination Success of Three North American Shrubs," The American Midland Naturalist 140(1), 129-139, (1 July 1998).[0129:IOSPBF]2.0.CO;2
Received: 9 June 1997; Accepted: 1 September 1997; Published: 1 July 1998
Get copyright permission
Back to Top