Species extinction in complex ecological networks

LAGUNA, MARIA FABIANA; ABRAMSON, GUILLERMO; KUPERMAN, MARCELO N.; MONJEAU, ADRIAN; LANATA, JOSÉ LUÍS

Punta del Este

Conferencia; 5th Dynamics Days Latin America and the Caribbean; 2018

5th Dynamics Days Latin America and the Caribbean

Our model represents a simplified scenario, inspired by the occupation of the American continent, that allows us to analyze possible scenarios based on three groups of causes of extinction: biological, anthropic and environmental. Our first approach consists of a two-level trophic network, consisting of a hunter and two herbivores in hierarchical competition, one of them being the "megafauna". We use a stochastic dynamic model that allows us to study the role of spatial fluctuations and correlations. We show how the presence of hunters causes the extinction of megafauna even in habitats that would allow coexistence. This occurs even when the predatory pressure on the megafauna is less than on the surviving herbivore, thus avoiding the need for an "overkill". Among other details, we show that the time from invasion to extinction is in relation to the size of the system, obeying a law that corresponds very well to paleontological evidence, both qualitatively and quantitatively.