Dispersión de semillas de Prosopis por mamíferos nativos y exóticos en el desierto del Monte (Ischigualasto, San Juan, Argentina).

CAMPOS VALERIA; PECO BEGOÑA; CAMPOS CLAUDIA; MALO JUAN; GIANNONI STELLA; SUAREZ FRANCISCO

Tafi del Valle, Tucuman

Congreso; XXI Jornadas Argentinas de Mastozoología; 2007

Native and exotic mammals can play a role in the dispersal of Prosopis seeds by endozoochory in arid zones of Argentina. Our specific goals were to quantify the seeds of Prosopis flexuosa, P. chilensis and P. torquata contained in the faeces of native (Dolichotis patagonum, Lama guanicoe) and exotic mammals (donkey and Lepus europaeus), and to determine mortality rate, germination rate and germination speed in seeds borne in faeces compared to those collected from trees. In 2006 we collected seeds directly from trees, and removed seeds from the faeces of mammals. We counted and classified the seeds as apparently healthy and damaged. Germination assays were performed, and rate of mortality, germination rate, and speed of germination were measured. Seeds of P. torquata and P flexuosa were found in the dung of L. guanicoe, L. europaeus and D. patagonum, whereas only P flexuosa seeds appeared in donkey faeces. Seeds of P. chilensis were only found in the faeces of L. guanicoe. The passage through the digestive tract of animals modified seed germination capacity and speed, with great variability between animals and a generalized tendency to speed up the process and increase the percentage of germinating seeds. On comparing between animals, the number of effects produced on seeds by L. guanicoe stood out in relation to the case of the donkey, that increased neither germination rate nor speed. Differences in the effect of both smaller-sized herbivores on seeds were much smaller. Endozoochory by large herbivores produced the highest rates of seed mortality.