CONICET | Buscador de Institutos y Recursos Humanos

For endozoochorous species, the quality component of seed dispersal effectiveness depends inpart on the treatment seeds receive in the animal?s gut. Covering a variety of taxa, diet, digestionsystem and body size of Prosopis flexuosa seed dispersers, we analysed differences amongspecies in (1) mean retention time of ingested seeds, (2) recovery of viable seeds, (3) seed germinationin comparison with seeds collected from trees and (4) germination of seeds after twodifferent periods of retention in the gut. Feeding experiments were conducted with captiveindividuals of Dolichotis patagonum, Lycalopex gymnocercus, Rhea americana, Chelonoidischilensis and Lama guanicoe. On the first day, we provided them with fruits containing controlledamounts of seed, and on the subsequent days, we collected faeces in order to recoverseeds. We performed germination and viability tests on seeds coming from faeces and collectedfrom trees. The results showed differences among species in the mean retention timeof seeds. Chelonoidis chilensis had the longest mean retention time, but its effect on seedrecovery and germination was similar to that of the other species, except for L. guanicoe,which showed the lowest seed recovery. When scarification and promotion of seed germinationwere considered, herbivorous mammals and tortoises (L. guanicoe, D. patagonum andC. chilensis) were the ones increasing germinability, whereas R. americana and L. gymnocercusdid not significantly increase final seed germination percentage, which was similar to that forseeds collected from trees. P. flexuosa seeds receive a variety of treatments from endozoochorousdispersers, which might result in an overall fitness benefit for a plant living in unpredictableenvironments.