Main content area

Ecosystem spatial self-organization: Free order for nothing?

Dong, Xiaoli, Fisher, Stuart G.
Ecological complexity 2019 v.38 pp. 24-30
ecosystems, landscapes, spatial variation
Ecosystems are complex adaptive systems (CAS) by nature, which means that macroscopic patterns and properties emerge from, and feed back to affect, the interactions among adaptive individual ecological agents. These agents then further adapt (genetically) to the outcomes of those interactions. The concept of self-organization has become increasingly important for understanding ecosystem spatial heterogeneity and its consequences. It is well accepted that ecosystems can self-organize, and that resulting spatial structures carry functional consequences. Feedbacks from the outcome of spatial pattern to the individual agents from which patterns emerge, are an essential component of the definition of CAS but have been rarely examined for ecosystems. We explore whether spatial self-organization provides a mechanism for such feedback for ecosystems as CAS, that is, whether ecosystem-level outcomes of self-organized patterning could feed back to affect or even reinforce local pattern-forming processes at the agent level. Diffuse feedbacks of ecological and evolutionary significance ensue as a result of spatial heterogeneity and regular patterning, whether this spatial heterogeneity results from an underlying template effect or from self-organization. However, feedbacks directed specifically at pattern-forming agents to enhance pattern formation—reinforcing feedback—depend upon the level of organization of agents. Reinforcing evolutionary feedbacks occur at the individual level or below. At the ecosystem level, evidence for mechanisms of feedback from outcomes to patterning to agents forming the patterning remain tenuous. Spatial self-organization is a powerful dynamic in ecosystem and landscape science but feedbacks have been only loosely integrated so far. Self-organized patterns influencing dynamics at the ecosystem level represent “order for free”. Whether or not this free order generated at the ecosystem level carries evolutionary function or is merely epiphenomenal is a fundamental question that we address here.