Community composition as an overlooked driver of spatial population synchrony

Area of Science:

• Ecology
• Population Dynamics
• Biodiversity Research

Background:

• Animal populations exhibit synchronized fluctuations, influenced by dispersal, environmental factors (Moran effect), and consumer-resource dynamics.
• The role of biotic interactions and community composition (beta-diversity) in mediating spatial population synchrony is not fully understood.
• Disentangling drivers of population synchrony in natural systems is challenging.

Purpose of the Study:

• To test if compositional differences among communities (beta-diversity) reduce spatial population synchrony.
• To investigate the influence of biotic interactions on metapopulation dynamics.
• To assess the spatial insurance effect of beta-diversity on species persistence.

Main Methods:

• Utilized an extensive dataset of fish population abundance time-series across European river networks.
• Analyzed the relationship between beta-diversity and spatial population synchrony.
• Controlled for geographic separation, environmental dissimilarity, and Moran effects.

Main Results:

• Higher beta-diversity was significantly associated with reduced spatial population synchrony within river networks.
• This effect was independent of geographic distance, environmental similarity, and the Moran effect.
• Community heterogeneity provides a spatial insurance effect, promoting asynchrony between populations.

Conclusions:

• Beta-diversity plays a crucial role in metapopulation dynamics by reducing spatial synchrony.
• Community assembly and compositional differences contribute to metapopulation stability and species persistence.
• Loss of beta-diversity due to biotic homogenization may threaten ecosystem stability and species survival.