SELF-ORGANIZING SYSTEMS ACROSS SCALES

Over the past few years, ecologists have increasingly recognized the e xistence of strong self-reinforcing (or self-organizing) interactions within systems at a variety of scales. Positive feedback within food c hains has been reported from terrestrial and aquatic ecosystems. Accum ulating evidence supports the existence within communities of cooperat ive guilds tit-for-tat relationships based on diffuse mutualisms and f avored by environmental unpredictability. At the landscape level, both real world experience and models indicate that processes such as hydr ology and the propagation of disturbance can be strongly self-reinforc ing (i.e. the landscape structure supports the process, and vice versa ). Hence the picture emerges of a hierarchy of self-organizing systems that span food chains, communities and landscapes/regions.