Endozoochory by native and exotic herbivores in dry areas: consequences for germination and survival of Prosopis seeds.

CAMPOS, C., PECO, B., CAMPOS, V., MALO, J., GIANNONI, S. Y SUÁREZ, F.

SEED SCIENCE RESEARCH

Cambridge University

Año: 2008 vol. 18 p. 91 - 100

0960-2585

Mammalian herbivores can play a role in theendozoochorous dispersal of Prosopis seeds in thearid zones of Argentina, and the introduction of exoticmammals can change relevant parameters of theplant’s reproductive ecology. Our specific goals wereto quantify the seeds of Prosopis flexuosa, P. chilensisand P. torquata contained in the faeces of native [mara(Dolichotis patagonum), guanaco (Lama guanicoe)]and exotic [donkey (Equus asinus) and hare (Lepuseuropaeus)] mammals, and to determine the mortality,germination percentage and germination speed ofseeds borne in faeces, compared with those collectedfrom trees. In 2006, seeds were collected directly fromtrees or removed from mammal faeces. Seeds werecounted and classified as apparently healthy ordamaged. P. torquata and P. flexuosa seeds werefound in the dung of guanaco, hare and mara,whereas only P. flexuosa seeds appeared in donkeyfaeces. P. chilensis seeds were only found in guanacofaeces. There was a notable relative abundance ofseeds contained in small herbivore faeces incomparison to the large herbivores. The passagethrough the digestive tract of animals modified seedgermination capacity and speed, with great variabilitybetween animal species. Guanacos had greatereffects than donkeys on mortality, germination percentageand germination speed. Differences betweenthe effects of both smaller-sized herbivores on seedswere much smaller.