Revista chilena de historia natural
Print version ISSN 0716-078X
HERNANDEZ-LADRON DE GUEVARA, IVETTE et al. Seed dispersal by birds in a cloud forest landscape in central Veracruz, Mexico: Its role in passive restoration. Rev. chil. hist. nat. [online]. 2012, vol.85, n.1, pp. 89-100. ISSN 0716-078X. http://dx.doi.org/10.4067/S0716-078X2012000100007.
Seed dispersal by birds may play a major role in the successful natural forest restoration process as birds can deposit pioneer and primary seeds species, thereby defining the recovery of plant community composition over time. In this study, seed ingestion and dispersion by frugivorous birds were analyzed as processes facilitating the restoration of tropical cloud montane forests in central Veracruz, Mexico. Birds were classified according to their affinity to the forest and their preference to a particular forest stratum, in order to determine whether these factors were related to the richness, abundance and diversity of ingested and dispersed seeds. We analyzed 93 fecal samples from 23 bird species. A total of 2699 seeds from 17 plant species were found in the fecal samples, the most abundant seed was from the shrub Conostegia xalapensis. We analyzed the correlation between seed size and beak size for the six most frequently captured bird species. We also evaluated the effect of bird ingestion on seed germination by performing two experiments, the first one using the total number of seeds found in fecal samples, and the second one using C. xalapensis seeds that were administered artificially to the birds and their germination compared with control seeds. We found significant differences among the ingested seed diversity indexes for the most commonly captured birds, which supports a differential seed consumption and dispersion. However, there were no significant differences of the seed abundance and richness between birds with different forest affinity or forest stratum preference. Also, there was no significant association between seed size and the height and the width of the beak, but there was a difference found in the length measured from the base and from the nostrils. From the total seed species, 59 % germinated from fecal samples belonging to 78 % of the bird species. As has been suggested for lowland tropical forests, this study also showed that in tropical cloud montane forests birds are good dispersal agents for a high diversity of plant species belonging to secondary forests, as well as dispersers of plant species from primary forest, acting therefore, as facilitators of forest succession process.
Keywords : Conostegia xalapensis; germination; forest restoration; frugivorous birds.