Abstract
Aim The impact of global change on biodiversity is commonly assessed in terms of changes in species distributions, species richness and species composition across communities. Whether and how much interactions between species are also changing is much less documented and mostly limited to local studies of ecological networks. Moreover, we largely ignore how biotic homogenisation (i.e. the replacement of a set of diverse and mainly specialist species by a few generalists) is affecting or being affected by changes in the structure of species interactions. Here, we approximate species interactions with species associations based on the correlation in species spatial co-occurrence to understand the spatio-temporal changes of species interactions and their relationship to biotic homogenisation.
Location France.
Time period 2001-2017.
Major taxa studied Common breeding birds.
Methods We use network approaches to build three community-aggregated indices to characterise species associations and we compare them to changes in species composition in communities. We evaluate the spatial distribution and temporal dynamics of these indices in a dataset of bird co-abundances of more than 100 species monitored for 17 years (2001-2017) from 1,969 sites across France. We finally test whether spatial and temporal changes of species associations are related to species homogenisation estimated as the spatio-temporal dynamics of β-diversity.
Results We document a non-random spatial distribution of both structure and temporal changes in species association networks. We also report a directional change in species associations linked to β-diversity modifications in space and time, suggesting that biotic homogenisation affects not only species composition but also species associations.
Main Conclusions Our study highlights the importance of evaluating changes of species association networks, in addition to species turnover when studying biodiversity responses to global change.
Competing Interest Statement
The authors have declared no competing interest.
