Living in a world of ghosts: seed dispersal by megafauna in the Pantanal of Brasil

Mauro Galetti, Dept. Ecologia, Universidad Estadual de São Paulo, UNESP, Brasil.
Fecha: 18 de Marzo, 2004, 18:30 h
Lugar: Salón de Grados, Facultad de Biología (edificio rojo ), campus de Reina Mercedes

Abstract

One of the seed dispersal anachronisms is the so-called "megafauna syndrome", has been the subject of considerable debate stemming on a lack of specific predictions and precise definitions. On the other hand, it is clear that many large fruit species "unfit" to the living seed dispersers.  South America was the land of large mammals until the end of the Pleistocene, less than 10,000 years ago.  Giant sloths, horses, large armadillos and many other odd creatures certainly played a key role on the vegetation structure and in the fruit attributes. In this talk, I will present some key attributes that makes a fruit "megafauna syndrome" and preliminary results from a field study in the Pantanal of Brasil. The Pantanal is the largest wetland in the world (1/4 of the area of Spain) and holds an anachronic community of fruits. I will also present some new findings about how the megafauna fruits survived without their dispersers and what are the consequences of losing such mega-dispersers.

Papers to read:

Barlow, C. 2000, The ghosts of evolution. Nonsensical fruit, missing partners, and other ecological anachronisms. Basic Books, New York.

Howe, H. F. 1985. Gomphothere fruits: a critique. The American Naturalist 125:853-865.

Janzen, D. H. 1981. Enterolobium cyclocarpum seed passage rate and survival in horses, Costa Rican Pleistocene seed dispersal agents. Ecology 62:593-601.

Janzen, D. H. 1982. Natural history of guacimo fruits   (Sterculiaceae: Guazuma ulmifolia ) with respect to consumption by large mammals. American Journal of Botany 69:1240-1250.

Janzen, D. H., and P. S. Martin. 1982. Neotropical anachronisms: the fruits the gomphotheres ate. Science 215:19-27.