Species associations in common bird communities are declining

As the state of biodiversity worsens, the dynamics of species interactions is a growing conservation concern. However, estimating and monitoring species interactions across large spatial and temporal scales remain challenging. Here, we assess changes in the number and type of pairwise associations using large-scale spatial and temporal data on the French avifauna. We estimate species associations through space and time for 109 species monitored across 1,969 sites during 17 years, and we show their ecological significance by testing their relationships with species functional proximity or shared habitat preference. We finally track temporal changes in reconstructed association networks. We show that birds’ local association networks were less and less connected through the study period. This decrease in network connectance does not similarly affect the different types of species associations. Overall, we show that large-scale temporal monitoring of species association networks can reveal overlooked consequences on how communities can cope with global change.