The effect of space in plant-animal mutualistic networks: insights from a simulation study

MORALES, J. M.; VÁZQUEZ, D. P.

OIKOS

WILEY-BLACKWELL PUBLISHING, INC

Año: 2008 vol. 117 p. 1362 - 1370

0030-1299

The topology of plant-animal mutualistic networks has the potential to determinethe ecological and evolutionary dynamics of interacting species. Many mechanismshave been proposed as explanations of observed network patterns; however, the factthat plant-animal interactions are inherently spatial has so far been ignored. Using asimulation model of frugivorous birds foraging in spatially explicit landscapes we evaluated how plant distribution and the scale of bird movement decisions influenced speciesinteraction probabilities and the resulting network properties. Spatial aggregation andlimited animal mobility restricted encounter probabilities, so that the distribution ofanimal visits per plant deviated strongly from the binomial distribution expected fora well-mixed system. Lack of mixing in turn resulted in a strong decrease in networkconnectance, a weak decrease in nestedness, stronger interactions, greater strengthasymmetry and the unexpected presence/absence of some interactions. Our resultssuggest that spatial processes may contribute substantially to structure plantanimalmutualistic networks.