Behavioral self-organization underlies the resilience of a coastal ecosystem

Abstract

Self-organized spatial patterns occur in many terrestrial, aquatic, and marine ecosystems. Theoretical models and observational studies suggest self-organization, the formation of patterns due to ecological interactions, is critical for enhanced ecosystem resilience. However, experimental tests of this cross-ecosystem theory are lacking. In this study, we experimentally test the hypothesis that self-organized pattern formation improves the persistence of mussel beds (Mytilus edulis) on intertidal flats. In natural beds, mussels generate selforganized patterns at two different spatial scales: regularly spaced clusters of mussels at centimeter scale driven by behavioral aggregation and large-scale, regularly spaced bands at meter scale driven by ecological feedback mechanisms. To test for the relative importance of these two spatial scales of self-organization on mussel bed persistence, we conducted field manipulations in which we factorially constructed small-scale and/or large-scale patterns. Our results revealed that both forms of self-organization enhanced the persistence of the constructed mussel beds in comparison to nonorganized beds. Small-scale, behaviorally driven cluster patterns were found to be crucial for persistence, and thus resistance to wave disturbance, whereas large-scale, self-organized patterns facilitated reformation of small-scale patterns if mussels were dislodged. This study provides experimental evidence that self-organization can be paramount to enhancing ecosystem persistence. We conclude that ecosystems with self-organized spatial patterns are likely to benefit greatly from conservation and restoration actions that use the emergent effects of self-organization to increase ecosystem resistance to disturbance.self-organization | resilience | multiscale patterns | ecosystems | mussels

Putting self‐organization to the test: labyrinthine patterns as optimal solution for persistence

“…We demonstrated that not organizing in spatial patterns, whether at low or high densities, was not sustainable. Tradeoffs between being the right shape and size to maximize facilitation in terms of decreasing dislodgment risk (de Paoli et al 2017) and minimizing competition have been shown for other ecosystem engineers, such as the saltmarsh plant Spartina anglica. In S. anglica systems, dislodgement is decreased by greater shoot densities, but densely packed tussocks limit light penetration.…”

“…The theoretical emergent properties of spatial self-organization proposed for patterned ecosystems as diverse as arid bushlands, patterned peatlands and mussel beds have been subject to very limited experimental verification (de Paoli et al 2017). Here, using patterns observed in realworld mussel beds, we provide a solid and process-oriented experimental test on the benefits of (presumably self-organized) patterning for mussels, and highlight its importance for both restoration practices and the optimization of culturing techniques (Guichard 2017).…”

“…Self-organization is hypothesized to be driven by the interplay of short-range facilitative mechanisms that allow organisms to cope with limited resources or harsh environments (Rietkerk and van de Koppel 2008), and long-range mechanisms of inhibition and competition. While the ubiquity of pattern formation has been well-studied and predicted by theoretical models, empirical mechanistic studies have been limited on how these patterns affect ecosystem resistance (de Paoli et al 2017), i.e. the ability of a system to remain 'unchanged' despite disturbance (Grimm and Wissel 1997).…”

Facilitating foundation species: The potential for plant–bivalve interactions to improve habitat restoration success

“…Recent studies have shown that promoting positive interactions between individuals of the same species can increase restoration success (de Paoli et al, 2017; Silliman et al, 2015; van der Heide et al, 2007), highlighting the importance of facilitative interactions in restoring ecosystem‐engineering species (Maxwell et al, 2017). Facilitative interactions between ecosystem engineers may be equally important for promoting resilience and recovery (Angelini et al, 2016; Derksen‐Hoojiberg et al, 2018; Renzi, He, & Silliman, 2019; van de Koppel et al, 2015), but <3% of restoration projects have integrated interspecific interactions (Zhang et al, 2018).…”

Multimodalin situdatalogging quantifies inter-individual variation in thermal experience and persistent origin effects on gaping behavior among intertidal mussels (Mytilus californianus)

“…Although mussels are nominally sessile as adults, mussel beds are dynamic systems where individuals may move themselves within the mussel matrix. Movement is thought to be driven by the need to achieve a better position for feeding, or to reduce the risk of dislodgement or predation, and could possibly be used to reduce exposure to the sun (Bertness and Grosholz, 1985;de Paoli et al, 2017;Harger, 1968;Robles et al, 2009). Mussels attach themselves to the substratum and to neighbors using flexible byssal threads that degrade over time and can be selectively released by the mussel, but the formation of new threads is energetically costly and is limited at high flow speeds (Carrington et al, 2008).…”