Increased coupling between subpopulations in a spatially structured environment can lead to population outbreaks

Area of Science:

• Ecology
• Conservation Biology
• Theoretical Biology

Background:

• Habitat destruction and fragmentation are primary drivers of biodiversity loss.
• A robust theoretical framework for predicting species' responses to habitat changes is needed.
• Metapopulation dynamics are crucial for understanding species persistence in fragmented landscapes.

Purpose of the Study:

• To investigate species dynamics in a two-habitat system with varying migration intensity.
• To explore the theoretical underpinnings of metapopulation responses to habitat coupling.
• To identify distinct regimes of metapopulation dynamics under different interaction intensities.

Main Methods:

• Utilized space-discrete and continuous metapopulation dynamic models.
• Employed computer simulations to analyze subpopulation dynamics in a patchy environment.
• Assessed species responses under bistable subpopulation dynamics with differing parameters.

Main Results:

• Identified two distinct metapopulation dynamics regimes: gradual decrease or sudden increase in total abundance.
• Demonstrated that increased migration intensity can trigger either a 'self-excitation' or 'self-inhibition' dynamic.
• Showed robustness of these regimes to model choice (discrete/continuous) and habitat size variations.

Conclusions:

• Metapopulation dynamics exhibit complex behaviors, including sudden shifts in abundance, influenced by migration intensity.
• The interplay between subpopulations can lead to either positive or negative feedback loops affecting overall population size.
• Habitat size asymmetry can alter the dominant dynamic regime, potentially shifting from self-excitation to self-inhibition or vice versa.