ECOLOGICAL FILTERING DURING MAJOR DISPERSALS: UNDERSTANDING THE SELECTIVITY OF MIGRATION DURING THE GREAT AMERICAN BIOTIC INTERCHANGE

The faunas of the Americas as we know them today are a relatively new occurrence. The closure of the Isthmus of Panama led to a series of migrations that shaped the biotas of North and South America. This event, termed the Great American Biotic Interchange (GABI), peaked for mammals approximately 2.5 Ma ago. Much of the past work on GABI has focused on the uncertain timing of the emergence of the isthmus of Panama, and on documenting those taxa that successfully crossed. However, the nature of ecological influences on patterns of GABI migration have been largely unexplored. I used Ecological Niche Modeling (ENM) to examine geographic and climatic predictor variables that may help to explain dispersal patterns for various taxa as a function of suitable niche space. One migrant from South America, the armadillo like Glyptotherium, serves as a case study to show the connectivity of suitable habitat throughout Central America, and provides evidence for a possible migration corridor through the Antilles.