Resilient ecosystems are the backbone of a sustainable environmental support system. A key to resilience is anticipating how things can go wrong and preparing for the worst. There are many ways to achieve resilience:
Redundancy: duplication and diversification of function provide backups for when things go wrong. This principle is most conspicuous in the design of modern spacecraft, which have extensive backup systems to replace parts of the spacecraft that fail to function properly. Redundancy is prominent in natural ecosystems. The presence of species with overlapping ecological roles and niches contributes to the resilience of ecosystems.
Low dependence on human inputs: sustainable human -
ecosystem interaction is associated with ecosystems that have small human inputs. Nature does most of the work. Large human inputs reduce resilience because sooner or later something will happen that interferes with a society’s ability to provide the inputs. The collapse of Middle Eastern civilizations when irrigation ditches were clogged with sediment is an example (see Chapter 10).
Resilience is desirable, but it can conflict with other social objectives that are equally beneficial. Efficiency, for example, has become crucial for modern commercial enterprises because low operating costs are essential for survival. Economic efficiency and resilience are often in conflict because the redundancy that reinforces resilience requires extra cost and effort. Economic pressures to reduce resilience are increasing as competition tightens in the global economy.