Bascompte, J., Jordano, P., and J.M. Olesen. 2006. Asymmetric coevolutionary networks facilitate biodiversity maintenance. Science 312: 431-433.
The mutualistic interactions between plants and their pollinators or seed dispersers have played a major role in the maintenance of Earth’s biodiversity. To investigate how coevolutionary interactions are shaped within species-rich communities, we characterized the architecture of an
array of quantitative, mutualistic networks spanning a broad geographic range. These coevolutionary networks are highly asymmetric, so that if a plant species depends strongly on an animal species, the animal depends weakly on the plant. By using a simple dynamical model, we showed that asymmetries inherent in coevolutionary networks may enhance long-term coexistence and facilitate biodiversity maintenance.
|Photo: Interactions among plant and animal mutualists can be depicted not only by their presence/absence, but also by their strength, i.e., the degree of mutual interdependence. Asymmetries in mutual dependence strength are a universal property of these mutualistic interactions.|