Germination response of Lithraea molleoides seeds is similar after passage through the guts of several avian and a single mammalian disperser

Abstract

Seed dispersal by vertebrate frugivores plays an important role in plant population dynamics and community structure. The gut treatment may modify the germination response of seeds; often the specific effects of seed ingestion are not consistent among frugivorous taxa. In the Chaco mountain woodlands of Argentina, an ecosystem threatened by human activities, frugivorous birds enhance the seed germination of the most abundant fleshy-fruited plants. However, the effect of the identity of dispersers on seed germination remains unknown. In this work, we evaluated and compared the seed germination response of Lithraea molleoides (Vell.) Engl. (the dominant tree of the region) to gut passage through three Turdus species and the Pampa Fox (Lycalopex gimnocercus). Owing to anatomical differences between the Turdus species and Pampa Fox, we expected to observe higher seed germination in the seeds treated by the gut of Turdus species compared with those that have passed through the Pampa Fox’s gut. Our results showed that germination response of L. molleoides seeds was positively related to gut passage through Turdus species and Pampa Foxes (without differences among seed dispersers). Consequently, both the avian species and the Pampa Fox contribute positively to the dispersal and germination of L. molleoides seeds.