COS 37-4 - Reorganization of interaction networks modulates the persistence of colonizing species

Tuesday, August 8, 2017: 9:00 AM
C122, Oregon Convention Center
Serguei Saavedra1, Simone Cenci1, Ek del-Val2, Karina Boege3 and Rudolf P. Rohr4, (1)Civil and Environmental Engineering, MIT, Cambridge, MA, (2)Centro de Investigaciones en Ecosistemas, Morelia, Mexico, (3)Instituto de Ecologia, Universidad Nacional Autónoma de México, (4)Biology, University of Fribourg, Fribourg, Switzerland

Ecological interaction networks constantly reorganize as interspecific interactions change across successional stages and environmental gradients. This reorganization can also be associated with the extent to which species change their preference for types of niches available in their local sites. Despite the pervasiveness of these interaction changes, previous studies have revealed that network reorganizations have a minimal or insignificant effect on global descriptors of network architecture, such as: connectance, modularity, and nestedness. However, little is known about whether these reorganizations may have an effect on community dynamics and composition. To answer this question, we study the multi-year dynamics and reorganization of plant-herbivore interaction networks across secondary successional stages of a tropical dry forest. We develop new quantitative tools based on a structural stability approach to estimate the potential impact of network reorganization on species persistence. Then, we investigate whether this impact can explain the likelihood of persistence of herbivore species in the observed communities.


We find that resident (early-arriving) herbivore species increase their likelihood of persistence across successional stages. Importantly, we demonstrate that, in late successional stages, the reorganization of interactions among resident species has a strong inhibition effect on the likelihood of persistence of colonizing (late-arriving) herbivores. These findings support earlier predictions suggesting that, in mature communities, changes of species interactions can act as community-control mechanisms (also known as priority effects). Furthermore, our results illustrate that the dynamics and composition of ecological communities cannot be fully understood without attention to their reorganization processes, despite the invariability of global network properties.