Evaluating multiple determinants of the structure of mutualistic networks

VÁZQUEZ, D. P.; CHACOFF, N. P.; CAGNOLO, L.

ECOLOGY

ECOLOGICAL SOC AMER

Año: 2009 vol. 90 p. 2039 - 2046

0012-9658

The structre of mutualistic networks is likely to result from the simultaneous influence of neutrality and the constraints imposed by complementarity in species phenotypes, phenologies, spatial distributions, phylogenetic relationships and sampling artifacts. We develop a conceptual and methodological framework to evaluate the relative contributions of these potential determinants. Applying this approach to the analysis of a plant-pollinator network, we show that information on relative abundance and phenology succes to predict several aggregate network properties (connectance, nestedness, interaction evenness and interaction asymmetry). However, such information falls short of predicting the detailed network structure, leaving a large amount of variation unexplained. Taken together, our results suggest that both relative species abundance and complementarity in spatio-temporal distribution contribute substantially to generate observed network patters, but that this information is by no means sufficient to predict the occurrence and frequency of pairwise interactions. Future studies could use our methodological framework to evaluate the generality of our findings in a representative sample of study systems with contrasting ecological conditions.