Generalizations of the Moran effect explaining spatial synchrony in population fluctuations

Area of Science:

• Ecology
• Population Dynamics
• Environmental Science

Background:

• The Moran effect traditionally assumes linear density regulation in spatially separated populations.
• Environmental noise can synchronize population fluctuations, but this is less understood for nonlinear dynamics.

Purpose of the Study:

• To generalize the Moran effect for populations with nonlinear density regulation and spatial heterogeneity.
• To derive an expression for population size correlation considering spatial variations in dynamics and environmental covariates.

Main Methods:

• Utilized diffusion approximation to the theta-logistic model.
• Derived a mathematical expression for the correlation between population sizes.
• Analyzed the impact of spatial heterogeneity in dynamics and covariate effects.

Main Results:

• Spatial variation in dynamics generally reduces population synchrony.
• The influence of environmental covariates on synchrony is highly dependent on spatial heterogeneity.
• Nonlinear dynamics and spatial heterogeneity were shown to synchronize populations without individual exchange.

Conclusions:

• The generalized Moran effect accurately describes population synchrony under nonlinear dynamics and spatial heterogeneity.
• Spatial heterogeneity plays a critical role in modulating the impact of environmental covariation on population synchrony.
• This framework provides new insights into the mechanisms driving synchrony in ecological populations.