Metapopulational Structure and Community Assemblage in an ECHO Model

NAIRA PINTO; ALEJANDRA C VENTURA; ANDRES MOREIRA

Student Papers Santa Fe Complex Systems Summer School 2001

Santa Fe Institute

Lugar: Santa Fe, New Mexico, USA; Año: 2001 vol. 2001 p. 1 - 10

Space plays an essential role in forming ecological patterns and in molding evolutionary processes; both natural and human-caused discontinuity of habitats have large effects on how populations function. The metapopulational concept considers spaces as an assemblage of discrete suitable habitat patches embedded in a matrix of unsuitable habitats. Metapopulations, being constrained by this spatial structure, constitute an assemblage of discrete populations with migration among them. Therefore, the metapopulation concept provides a framework for studying ecological and evolutionary processes taking into account rather population dynamics (single species analyses) or ecological interactions (multispecies analyses). However, since both processes operate at the same time; are constrained by the same spatial scenario, and interact to produce observed patterns, it would be very useful to investigate intra and inter-specific phenomena simultaneously. In this project we attempted to extract essential features of natural metapopulations and use them to perform simulations in an ECHO model. ECHO combines genetic algorithms with agent-based model and thus allows the study of both ecological interactions and evolutionary dynamics. We have modified ECHO to simulate a system with closed species, considering both population dynamics within individual species and interaction among different species. Our goal was to investigate the emergent species´ distribution patterns in several different metapopulation structures -combinations of patches of different size and degree of isolation. We were able to obtain some characteristic features of metapopulational dynamics using ECHO components and laws. However, patterns of species´ distribution were not distinct among different sites in a simple metapopulation structure. We the discuss a possible explanation for this result.