Spatial trophic cascades in communities connected by dispersal and foraging

Area of Science:

• Ecology
• Metacommunity Dynamics
• Spatial Ecology

Background:

• Species interactions generate direct and indirect ecological effects.
• These interaction effects can propagate spatially through organismal movement.
• Understanding spatial propagation is crucial for ecosystem dynamics.

Purpose of the Study:

• To investigate the spatial propagation of pairwise interaction effects.
• To analyze how different types of movement (dispersal, foraging) influence interaction effects across space.
• To determine if local interaction effects correspond to metacommunity-level effects.

Main Methods:

• Utilized a spatially explicit metacommunity model.
• Simulated local sites connected by dispersal, foraging, or both.
• Analyzed the sign and magnitude of direct and indirect interaction effects.

Main Results:

• Indirect effects align with direct effects when species disperse.
• Indirect effects diverge from direct effects when foraging is prevalent.
• The type of movement significantly mediates the spatial propagation and correspondence of interaction effects.
• Local effects do not always predict metacommunity effects; this is movement-dependent.
• Interaction effects decay with distance between species.

Conclusions:

• Movement type critically shapes spatial interaction effects in metacommunities.
• Foraging-driven interactions introduce unpredictability in spatial effect propagation.
• Theoretical results underscore the importance of spatial context and movement in ecological interactions.