4 A Review on the Role of Endozoochory in Seed Germination A. TRAVESET , A.W. ROBERTSON AND J. RODRÍGUEZ-PÉREZ Introduction A large fraction of living plants produce fruits that attract animals (64% and 27% of gymnosperm and angiosperm lineages, respectively; Herrera and Pellmyr, 2002). In consuming them, animals can spread the seeds to more or less distant sites from the parent plant, thus contributing to plant regeneration and colonization of new sites (Willson and Traveset, 2000, and references therein). For millions of years both the pulp and seeds of fruit have been subjected to selective pressures exerted by frugivores and granivores. Fruit consumers, specifically, may show preferences for fruit traits such as size, shape, chemical composition and others, and have specific morphologies and physiologies of the digestive tract that affect the survival probability of the ingested seeds in different ways (Herrera and Pellmyr, 2002, and references therein). Seed traits are under further selective pressures imposed by a number of biotic (antagonistic fungi, insects and microbes; Cipollini and Levey, 1997) and abiotic factors (e.g. light, temperature, rainfall; Holl, 1999; Leishman et al., 2000) that influence the dormancy period, germination time and/or future seedling growth, which can ultimately determine germination and seedling success (Verdú and Traveset, 2005, and references therein). Therefore, the specific seed traits in an endozoochorous plant are a result of the combined selection imposed by frugivores, granivores and other biotic and abiotic factors. In this chapter, we evaluate the role of endozoochory on seed germination. We review the information gathered on germination patterns in experiments aimed at examining the effect of a seed’s passage through a frugivore’s gut, and give further directions on methods for future studies. Fruit treatment in the disperser’s digestive tract (which includes pulp separation from seeds and treatment of the seeds) can determine the capacity of seeds to germinate and, thus, is one of the components of 78 © CAB International 2007. Seed Dispersal: Theory and its Application in a Changing World (eds A.J. Dennis et al.) 04Seed Dispersal Ch 4 16/4/07 15:53 Page 78