06Seed Dispersal Ch 6

Despite the accumulation of a considerable body of literature about frugivory and seed dispersal of fleshy-fruited plants by vertebrates during the last decades (e.g. reviews in Howe and Smallwood, 1982; van der Pijl, 1982; Janzen, 1983; Howe, 1986; Howe and Westley, 1988; Stiles, 1989; Jordano, 2000; Herrera, 2002), and also previous editions of the Frugivores and Seed Dispersal: International Symposium/Workshop series (namely Estrada and Fleming, 1986; Fleming and Estrada, 1993; Levey et al., 2002), the habits of reptiles as frugivorous animals and their role as seed dispersers have rarely been considered. At most, they are regarded as agents of the past (Labandeira, 2002; Tiffney, 2004). Understandably, the literature has been dominated by studies on frugivorous birds, primates, ungulates and bats, which behave as important seed dispersers of vascular plants in many habitats. However, the pulp of fleshy fruits is also an important food resource for tortoises and turtles (MacDonald and Mushinsky, 1988; Milton, 1992; Jerozolimski, 2003) and for herbivorous and omnivorous lizards (Schoener et al., 1982; Dearing and Schall, 1992; Valido et al., 2003). Thus, one might expect that species included in both reptile groups would act as potential seed dispersers, but this has hardly ever been seriously considered. The exceptions are classic studies demonstrating the importance of herbivorous chelonians as seed dispersers (see Beccari, 1877; Borzí, 1911; Ridley, 1930; Rick and Bowman, 1961) and also some more recent publications (e.g. Racine and Downhower, 1974; Hnatiuk, 1978; Rust and Roth, 1981; Cobo and Andreu, 1988; Milton, 1992; Moll and Jansen, 1995; Varela and Bucher, 2002; Liu et al. 2004). In contrast to these animals, the reptile group upon which we focus in this chapter – the lizards (order Squamata: suborder Sauria), including around 4800 species worldwide – have received little attention as modern