Scale‐Dependent Feedback and Regular Spatial Patterns in Young Mussel Beds

TLDR

Theoretical ecologists predict that predator–prey interactions can generate large‑scale spatial patterns, yet empirical evidence remains scarce. We document regular spatial patterns in young mussel beds on soft sediments in the Wadden Sea. Scale‑dependent feedback—short‑range facilitation by wave protection and long‑range competition for algae—drives self‑organization of the beds. Self‑organization increases mussel productivity and resilience, enabling survival at algal concentrations that would otherwise preclude mussels in homogeneous beds, thereby shaping ecosystem function at larger scales.

Abstract

In the past decade, theoretical ecologists have emphasized that local interactions between predators and prey may invoke emergent spatial patterning at larger spatial scales. However, empirical evidence for the occurrence of emergent spatial patterning is scarce, which questions the relevance of the proposed mechanisms to ecological theory. We report on regular spatial patterns in young mussel beds on soft sediments in the Wadden Sea. We propose that scale‐dependent feedback, resulting from short‐range facilitation by mutual protection from waves and currents and long‐range competition for algae, induces spatial self‐organization, thereby providing a possible explanation for the observed patterning. The emergent self‐organization affects the functioning of mussel bed ecosystems by enhancing productivity and resilience against disturbance. Moreover, self‐organization allows mussels to persist at algal concentrations that would not permit survival of mussels in a homogeneous bed. Our results emphasize the importance of self‐organization in affecting the emergent properties of natural systems at larger spatial scales.