Tuesday, August 4, 2009: 8:00 AM-11:30 AM
Blrm C, Albuquerque Convention Center
Miguel A. Fortuna
Plant-animal mutualistic interactions have played a paramount role in the generation of biodiversity on Earth. Initial studies on coevolution focused on pairs of strongly interacting species, and emphasized specialization. In the last decades, a growing number of ecologists and evolutionary biologists advocated a community approach to mutualism, and found widespread examples of generalization. Currently, ecologists and evolutionary biologists have moved from the specialization vs. generalization debate to understanding how specialists and generalists interact forming complex networks of species interdependence. This has brought a full community-wide approach to mutualism, spurred by the recent existence of tools for representing and analyzing complex networks. The first stage of research in this field has been mainly devoted to describing the structure of these networks. Mutualistic networks have been found to be very heterogeneous (while the bulk of species have a few interactions, a few species are much more connected than expected by chance); nested (specialists interact with species that form well-defined subsets of the species generalists interact with); and build upon weak and asymmetric links among species. Thus, mutualisms are neither randomly organized, nor organized in compartments arising from tight, parallel specialization. Right now, ecologists and evolutionary biologists are moving beyond this descriptive first stage to start unraveling mechanisms and consequences of network structure. Specifically, the current most active areas of research explore: (1) similarities and differences across different interaction types (e.g., mutualism vs. antagonism); (2) the processes generating these network patterns; (3) their temporal dynamics; and (4) their consequences for conservation biology. These latter subjects are the topics we plan to review in this session, with the ultimate goal to increase information flow and to set up an agenda for the next few years. To this aim we have invited a sample of the most active researchers in this area representing seven different countries, different organism type (pollination, seed dispersal, antagonistic interactions), and approaches (structure, dynamics, and phylogenetic independent contrasts). After a brief overview, we will start by reviewing the architecture of these networks (talks by Olesen, and Lewinsohn), and the consequences of network structure for network functioning (talk by Fontaine). From here we will move to the evolutionary and ecological correlates of network structure (talks by Jordano and Rico-Gray), dynamics of networks (talk by Petanidou), and finally discuss why all this research is important for restoration, ecosystem services, and biological invasions (talk by Memmott).