Weaving trait co-occurrence networks from local to landscape scales to disentangle drivers of community functional structure.

Functional composition of communities arises from the interaction between local environment and species traits, reflecting the interplay between local filters and species performance. Yet, trait-based approaches often overlook regional heterogeneity, which is defined by geographic or environmental distances between communities. This limits our ability to disentangle the role of local or regional drivers for functional assembly and hinders our understanding of both global change impacts and community functioning dynamics. To address this, we expanded a functional network approach, shifting the focus from species–trait associations to trait–trait co-occurrences, enabling us to evaluate how network structure evolves from local to regional scales while integrating spatial and environmental gradients. We developed this approach using simulated and empirical metacommunities from 56 Swedish lakes (20 years) and 36 rivers (11 years). We  progressively merged communities by spatial proximity, environmental similarity, or random selection, constructing trait co-occurrence networks at each step and calculating several network indices  to track structural shifts across scales (e.g., edge density, graph strength). Our results revealed scale dependency in metacommunity functional structure by showing that lake functional assembly was primarily driven by environment, while river functionality was mostly driven by geographical proximity. By bridging local and regional perspectives from a metacommunity standpoint, our method expands current understanding of trait-functional assembly.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: David Cunillera-Montcusí, IFREMER (david.cunillera@dcm.cat)

Authors:

Anna Equisuany, GRECO, Institute of Aquatic Ecology, University of Girona  (anna.equisuany@udg.edu)

David Cunillera-Montcusí, IFREMER, DYNECO-LEBCO  (david.cunillera@dcm.cat)

Dani Boix, GRECO, Institute of Aquatic Ecology, University of  (dani.boix@udg.edu)

Miguel Cañedo-Argüelles, FEHM Research Group, IDAEA-CSIC  (mcanedo.fem@gmail.com)

Maria Antón-Pardo, Department of Microbiology and Ecology, University of Valencia  (m.teresa.anton@uv.es)

Carla Olmo, GRECO, Institute of Aquatic Ecology, University of Girona  (carla.olmo@udg.edu)

David Angeler, Museo Nacional De Ciencias Naturales, Spanish Research Council (MNCN-CSIC)  (David.Angeler@slu.se)

Xavier Quintana, GRECO, Institute of Aquatic Ecology, University of Girona  (xavier.quintana@udg.edu)

Zsófia Horváth, Institute of Aquatic Ecology, Centre for Ecological Research  (horvath.zsofia@ecolres.hu)

Stéphanie Gascón, GRECO, Institute of Aquatic Ecology, University of Girona  (stephanie.gascon@udg.edu)