Connectivity is not only a determinant for biodiversity at local and regional scale, but also for the functional structure of communities and its stability. Decreasing connectivity hinders dispersal among communities, changing biotic interaction networks, and eventually leading to the extinction of less competitive species. Thus, in isolated patches, species richness might decrease, while their contribution to beta diversity increase. In contrast, communities in central locations, more prone to mass effects, are expected to have more complex biotic interaction networks, because resources are not locally limited but subsidized by the ones of nearby. This would in turn increase community stability and would locally reduce the strength of biotic interactions. To test it, we have used data from a regional lake monitoring carried out from 1995 to 2015 (60 lakes in Sweden), and calculated the temporal species turnover, uniqueness, stability and biotic interactions of phytoplankton and invertebrates. We have then combined this information with the centrality metrics and the available environmental data from each monitored lake within a lake network obtained from a global lake database. Our preliminary results showed that the number of biotic interactions was positively related to species richness, turnover, and uniqueness, but negatively related to community stability. We also noticed that the number of interactions not only responded to isolation but also to environmental conditions, which is also true for biodiversity metrics at local and regional scale.

Primary Presenter: Stéphanie Gascón, University of Girona (stephanie.gascon@udg.edu)

Authors:

Stéphanie Gascón, University of Girona, Institute of Aquatic Ecology, GRECO  ()

David Cunillera-Montcusí,  1. Universidad de la República, Centro Universitario Regional del Este (CURE),Departamento de Ecología y Gestión Ambiental; 2. University of Barcelona, Ecology and Environmental Sciences, FEHM-Lab. Section of Ecology, Department of Evolutionary Biology; 3. University of Girona, Institute of Aquatic Ecology, GRECO  ()

Matías Arim, University de la República, Centro Universitario Regional Este (CURE),Departamento de Ecología y Gestión Ambiental  ()

Maria Antón-Pardo, University of Valencia, Cavanilles Institute of Biodiversity and Evolutionary Biology  ()

David Angeler, Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment  ()

Robert Ptacnik, Wasser Cluster Lunz  ()

Zsófia Horváth, Centre for Ecological Research, Institute of Aquatic Ecology  ()

Ana Inés Borthagaray, University de la República,Centro Universitario Regional Este (CURE), Departamento de Ecología y Gestión Ambiental  ()