Bridging meta-analysis and the comparative method: A test of seed size effect on germination after frugivores' gut passage

5 páginas, 3 figuras, 1 tabla.

Most studies using meta-analysis try to establish relationships between traits across taxa from interspecific databases and, thus, the phylogenetic relatedness among these taxa should be taken into account to avoid pseudoreplication derived from common ancestry. This paper illustrates, with a representative example of the relationship between seed size and the effect of frugivore's gut on seed germination, that meta-analytic procedures can also be phylogenetically corrected by means of the comparative method. The conclusions obtained in the meta-analytical and phylogenetical approaches are very different. The meta-analysis revealed that the positive effects that gut passage had on seed germination increased with seed size in the case of gut passage through birds whereas decreased in the case of gut passage through non-flying mammals. However, once the phylogenetic relatedness among plant species was taken into account, the effects of gut passage on seed germination did not depend on seed size and were similar between birds and non-flying mammals. Some methodological considerations are given to improve the bridge between the meta-analysis and the comparative method.

We are grateful to D. Ackerly, C.K. Kelly, J. B. Losos, M. Pagel, A.P. Møller, J. Sánchez-Meca and L. Santamaría for their valuable comments. Special thanks are due to T. Garland who kindly provided the PDAP program and helped us with the data analysis. We also thank all authors who provided us with their unpublished data. This work is framed within projects BOS2001-0610 and AGL2001-1061. M.V. was granted with a Ramón y Cajal contract from the Ministerio de Educación y Ciencia Español during the preparation of this manuscript.

This work is framed within projects BOS2001-0610 and AGL2001-1061. M.V. was granted with a Ramón y Cajal contract from the Ministerio de Educación y Ciencia Español during the preparation of this manuscrip

Peer reviewed