Evaluating multiple determinants of the structure of plant-pollination networks

VÁZQUEZ, DIEGO; CHACOFF, NATACHA; CAGNOLO, LUCIANO

Milwaukee, Wisconsin, EEUU

Simposio; ESA Annual Meeting; 2008

The Ecological Society of America

The structure of mutualistic networks is likely to result from the simultaneousinfluence of neutrality and the constraints imposed by complementarity in species phenotypes,phenologies, spatial distributions, phylogenetic relationships, and sampling artifacts. Wedevelop a conceptual and methodological framework to evaluate the relative contributions ofthese potential determinants. Applying this approach to the analysis of a plant–pollinatornetwork, we show that information on relative abundance and phenology suffices to predictseveral aggregate network properties (connectance, nestedness, interaction evenness, andinteraction asymmetry). However, such information falls short of predicting the detailednetwork structure (the frequency of pairwise interactions), leaving a large amount of variationunexplained. Taken together, our results suggest that both relative species abundance andcomplementarity in spatiotemporal distribution contribute substantially to generate observednetwork patters, but that this information is by no means sufficient to predict the occurrenceand frequency of pairwise interactions. Future studies could use our methodologicalframework to evaluate the generality of our findings in a representative sample of studysystems with contrasting ecological conditions.