Self-organizing systems across scales

In a self-organizing (or self-reinforcing) system, structure and processes mutually reinforce one another. The system mayhave a random seed, but, once in-itiated, pulls itself up by its ownbootstraps and (within bounds)maintains order through internalinteractions. Kauffman' describesself-organizing systems as 'anti-chaotic', because unlike chaotic sys-tems (which are highly sensitive toinitial conditions), they channeldifferent initial conditions into thesame final state' 2. Organisms areclearly self-organizing, as are manyphysico-chemical systems. Chenand Bak3 suggest that the universemight be a self-organizing system,and the bootstrap theory of physicsholds that all nature exists '...byvirtue of mutually consistent re-lationships'4. Self-organization inecological systems is suggested bythe increasing recognition of eco-systems as thermodynamically open and far from equilibrium, with positive feedback as an im-portant organizing force5-1. These are common ingredientsof self-organization, though by themselves do not guarantee it.
Though the phenomenon of self-organization has beenrecognized for decades, within the past few years, variousresearchers have argued that self-organizing systems evolveto a critical state that Kauffman describes as balancing onthe edge of chaos1.2.6. In the words of Bak et al.2 '...ecologicalsystems are organized such that the different species "sup-port" each other in a way which cannot be understood bystudying the individual constituents in isolation. The sameinterdependence of species also makes the ecosystem verysusceptible to small changes or "noise". However, the systemcannot be too sensitive since then it cannot have evolvedinto its present state in the first place. Owing to this balancewe may say that such a system is "critical"'. Perry et (11.6 andKauffman' refer to such systems as poised: robust againstperturbations to which system components are adapted,but subject to threshold changes when the bounds of adap-tability are exceeded. O'Neill et al.12 call this 'metastability',and argue that it is a general property of ecological systems.Threshold transitions are increasingly reported in a variety ofnatural systems and are reproduced in models5 6.12-20, thoughthey might be produced by various mechanisms and are notin themselves proof of self-organization. These thresholdsdiffer from normal successional changes in that they are ir-reversible (at least within human timescales) without exter-nal intervention, and sometimes not even then. As KnowIton16puts it, once the straw has broken the camel's back, simplyremoving the straw does not allow the camel to rise again.
There are many questions regarding self-organization innature. How prevalent is it in ecological systems. and overwhat scales? How do self-organizing dynamics evolve? What does self-organization imply forecological dynamics, particularlythe existence of 'critical' states, theavoidance of thresholds and thesustainability of human interactionswith our life support systems? Mostresearch on self-organization hasbeen via simulation modeling oranalytical mathematics (Kauffman'and Murray21 review various as-pects of the formal theory). How-ever, my focus here is field ecology,particularly the degree to whichnatural patterns and processesmight signal self-organized behav-ior, and what that implies for eco-system stability and the evolutionof cooperation. Self-organizing (orself-reinforcing) behavior as usedhere refers to the creation of meta-stable dynamics through internalinteractions, including, but notnecessarily restricted to, positivefeedback.
Since all subglobal ecologicalsystems are open to transfers ofenergy and matter, self-organization in nature must beunderstood in relative terms - that is, system dynamicsmust involve not only internal interactions, but modificationof external forces such that they reinforce, or at least do notoverwhelm, internally generated order. It follows that inter-actions among scales and, in particular, boundary phenom-ena are central to understanding self-organization in ecol-ogy. A basic premise of this article is that natural systemscomprise a hierarchy of self-organizing (self-reinforcing)systems embedded within one another and stabilized bycooperative (tit-for-tat) relationships, the latter focused par-ticularly at spatial and temporal boundaries.