Document: SAN-3-419-188

Fish, mammals, or light?: Disperser-limited versus resource limited distribution of a riparian fig tree in a Costa Rican tropical rainforest.

BANACK, S.A.*, M.HORN and A.GAWLICKA

California State University, Fullerton. CA 98031 USA ¹

Abstract:
Fish, Brycon guatemalensis, have been proposed as the major dispersal agent for a fig tree (Ficus glabrata) at La Selva, Costa Rica. Figs, in general, are known for their non-specific (generalist) strategy of fruit dispersal. They represent an important part of the diet of a large number of animal species during the dry season and are often referred to as "keystone resources". We tested the null hypothesis that fish are the major disperser in this system by examining other potential seed dispersers. In addition, the distribution of the fig was examined in further detail. We determined that the fig was restricted to riparian habitat greater than 7 meters in width. In addition, the fig was limited by micro-habitat requirements and not seed dispersal. We identified four mammalian seed dispersers [kinkajou, howler monkey, and two species of fruit bats] that contribute to seed dispersal in Ficus glabrata. We established that Ficus seeds that pass through the guts of bats are viable. We demonstrated that light is the dominant factor limiting the establishment and growth of this species through greenhouse experiments. Using reciprocal transplants we showed that seedling establishment is a critical recruitment stage for this species and that transplants of established plants rather than seeds or small seedlings have a greater chance of survival.

Keywords: seed dispersal, rain forest

This abstract is being presented at: 2:45 PM in session:
Oral Session #68: Dispersal of Seeds and Fruits.