Landscape Changes

In the last section I have described three possibilities of landscape ontogenesis. Ontogenesis is a special case of changes in which opportunities are more connected with dynamics, and novelties are by definition more related to the concept of stochastic change.

We summarize briefly the three possibilities by which landscape ontogenesis operates:

"Opportunity" is a process that happens inside an aggregated unit (population, ecotope, or community) and can be considered the first level of a self-organizing process. The energy used to produce changes is shared inside the unit's components.

"Event" is a process that occurs between units (patches) and the allocated energy is extracted by the difference of information that characterizes each patch. The ecotones are the physical "localities" in which events are active. The establishment of ecotones determines changes in species composition and, more generally, an increase in the interpatch connectivity for matter, energy, information, and organisms. It also determines the self-organization of the configuration.

Finally "novelty" happens when a system is supplied by an extra "alien" energy, such as hurricanes in a tropical forest, the invasion of an aggressive species, or an earthquake. In this case, a new configuration appears in the system, substantially changing the history of the system and the direction of its dynamics.

According to the dissipative nature of living systems (Prigogine 1961, Odum 1983) and the opposite self-organization attitude of complex systems (Kauffman 1993), landscapes are shaped and modified continuously by internal and external forces that create order (information, sensu Stonier 1990, 1996) followed by a disordered, entropic state that shows oscillating dynamics (Holling 1973).

Landscapes can be considered dense, complex, networks of interactions between environmental factors (both forms and patterns, processes, and dynamics) that capture implicit as well as explicit properties of the environment (Phillips 1999).

But in order to maintain and sustain such a complex aggregate system (sensu Manson 2001), changes seem to be fundamental processes common to every scaled level of resolution at which a system is investigated.

0 0

Post a comment