Self-organization and landscape evolution

Abstract

Self-organization is common in earth surface systems, and related principles have been proposed as general principles applicable to geomorphic systems. Non-self-organizing behaviour is also observed in geomorphic systems, however. If a reasonable box-and-arrow diagram and associated qualitative interaction matrix can be devised for a geomorphic system, one can determine whether or not (or under what conditions) the system is self-organizing. Both self- organizing (at-a-station hydraulic geometry) and non-self-organizing (soil landscape evolution) geomorphic systems are illustrated. The development of topographic relief demonstrates the principle that landscape evolution may be characterized by both modes at different times or under different circumstances. Increasing relief, involving a mean divergence of elevations, may be self- organizing. Topographic development by decreasing relief, where elevations generally converge, is always non-self-organizing. Self-organization in geomorphology may be similar to steady-state equilibrium, in that its explanatory value lies not in general applicability, but in distinguishing between fundamentally different modes of landscape development.