The Open Biology Journal

2009, 2 : 101-113
Published online 2009 September 10. DOI: 10.2174/1874196700902010101
Publisher ID: TOBIOJ-2-101

RESEARCH ARTICLE
 Effectiveness of Dispersal of an Ornithocorous Cactus Myrtillocactus geometrizans (Cactaceae) in a Patchy Environment

Mónica G. Pérez-Villafaña, * and Alfonso Valiente-Banuet

* Address correspondence to this author at the Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México. Apartado Postal 70-275, C. P. 04510 México D.F., Mexico; E-mail: mperez@miranda.ecologia.unam.mx

ABSTRACT

Effectiveness of seed dispersal by different species that feed on the fruits of Myrtillocactus geometrizans was evaluated, considering both quantity and quality of dispersal, in a patch of tropical deciduous forest in Zapotitlán de las Salinas. Effectiveness was estimated to be strongly influenced by the post-foraging movements of the frugivores, leading us to suggest that the quality component of seed dispersal occupies a central role in the assessment of disperser effectiveness and to expect that dispersers that stay in the tropical deciduous forest patch after foraging would have highest effectiveness. Birds were the principal dispersers of M. geometrizans. This was particularly true of Phainopepla nitens, since this species showed a high fidelity within the tropical deciduous forest. These observations emphasize that it is important to determine the post-foraging habits of seed dispersers that may move across vegetation patches over the landscape in order to obtain a complete assessment of their role in Neotropical environments.

Keywords:

Arid zone, birds, cactaceae, , seed dispersal, Zapotitlan valley.