The Risk Of Orientor Optimization

Translating these general points into our ecosystem theory, it is obvious that two general processes are governing the dynamics of ecosystems. Besides growth and development processes, living systems are also susceptible to influences that move them back toward thermodynamic equilibrium. On the one hand, there are long phases of complexification. Starting with a pioneer stage, orientor dynamics bring about slow mutual adaptation processes with long durations, if there is a dominance of biological processes (see Ulanowicz, 1986a; Müller and Fath, 1998).

A system of interacting structural gradients is created that provokes very intensive internal flows and regulated exchanges with the environment (Müller, 1998). The processes are linked hierarchically, and the domain of the governing attractor (Figure 7.4) remains rather constant, whereupon optimization reactions provoke a long-term increase of orientors, efficiencies, and information dynamics.

The highest state of internal mutual adaptation is attained at the maturity domain (Odum, 1969). But the further the system has been moved away from thermodynamic equilibrium, the higher seems to be the risk of getting moved back (Schneider and Kay, 1994) because the forces are proportional to the gradients. The more the time has been used for i

Figure 7.4 Some characteristics of disturbances, after White and Jentsch (2001). The state of the ecosystem is indicated by one ecosystem variable. Due to the disturbance d2 the system is shifted from state A to B, the indicator value thus decreases significantly. The effective disturbance d2 has a higher abruptness (E), a longer duration (G), and a higher magnitude (F) than d1 which does not affect the system. Throughout the following development a high impact affects the trajectory D, which provides a long-term decrease of the ecosystem variable, while a more resilient ecosystem turns back to orientor dynamics (C).

Figure 7.4 Some characteristics of disturbances, after White and Jentsch (2001). The state of the ecosystem is indicated by one ecosystem variable. Due to the disturbance d2 the system is shifted from state A to B, the indicator value thus decreases significantly. The effective disturbance d2 has a higher abruptness (E), a longer duration (G), and a higher magnitude (F) than d1 which does not affect the system. Throughout the following development a high impact affects the trajectory D, which provides a long-term decrease of the ecosystem variable, while a more resilient ecosystem turns back to orientor dynamics (C).

Table 7.4 Some characteristics of mature ecosystems and their potential consequences for the system's adaptability1

Orientor function

Risk related consequences

High exergy capture High exergy flow density

High exergy storage and residence times High entropy production

High information

High degree of indirect effects High complexity High ascendancy and trophic efficiency

High degree of symbiosis

High intra-organismic storages

Long life spans

High niche specialization and K selection

The system operates on the basis of high energetic inputs — high vulnerability if the input pathways are reduced Many elements of the flow webs have lost parts of their autonomy as they are dependent on inputs which can be provided only if the functionality of the whole system is guaranteed - high risk of losing mutually adapted components

Exergy has been converted into biomass and information - high amount of potential fuel and risk of internal eutrophication Most of the captured exergy is used for the maintenance of the mature system - minor energetic reserves for structural adaptations High biotic and abiotic diversity - risk of accelerated structural breakdown if the elements are correlated

Many interactions between the components - increase of mutual dependency and risk of cascading chain effects Many components are interacting hierarchically - reduced flexibility Intensive flows and high flow diversities have resulted in a loss reduction referring to all single energetic transfers - changing one focal element can bring about high losses

Symbiosis is linked with dependencies, i.e., if it is inevitable for one or both partners - risk of cascading chain effects Energy and nutrients are processed and stored in the organismic phase - no short term availability for flexible reactions

Focal organisms have long-life expectancies - no flexible reactivity Organisms are specialized to occupy very specific niche systems and often have a reduced fecundity - reduced flexibility

'Maturity is attained due to a long-term mutual adaptation process. In the end of the development the interrelations between the components are extremely strong, sometimes rigid. Reactivity is reduced. If the constraints change this high efficient state runs the risk of being seriously disturbed.

complexification, the higher is the risk of being seriously hit by disturbance (Table 7.3), and the longer the elements of the system have increased their mutual connectedness, the stronger is the mutual interdependency (Chapter 5) and the total system's brittleness (Holling, 1986). Table 7.4 combines some features of mature ecosystems and lists some risk-related consequences of the orientor dynamics. In general, it can be concluded that the adaptability after changes of the constraints may be decreased when a high degree of maturity is attained.

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