A system is a set of interacting components forming a whole. We can cast a variety of entities as a system. Non-living systems, such as an automobile are simple and linear: a car tire has x-amount of miles it can travel before it’s expired, it cannot renew or repair itself. On the other hand, living systems, from cells to communities and organizations, are complex and non-linear: a living system can take in energy, export wastes, and adapt to change in surprising ways. Resilience to a mechanical engineer considers the capacity of a tire to take a shock (bump) and return to its intended function (round, firm, and rolling). Resilience to an systems scientist (ecologist) considers how a system can incorporate a shock while maintaining function, even though it may not look the same, it’s getting the job done.
An aquarium serves as an example of an “eco-system”. Aquarium components include fish, plants, water, filters, oxygen, and light. The light feeds the plants, the plants provide oxygen and food for the fish and the fish provides C02 and fertilizer to the plants. The loss of any component in this system compromises the aquarium’s resilience, to the point that a slight shock to any other component may push the aquarium beyond a threshold and into a dysfunctional state.
The aquarium system has obvious boundaries, but like all systems, the boundaries can be defined at different scales. For example, humans supply food to the fish, water to the aquarium, clean the filters, and add new plants and fish over time. Now the human becomes part of the aquarium system. The aquarium’s dependence on humans is term “social-ecological system”.
Turf lawns offer another example of “social-ecological systems”. The grass, soils, air, sunlight and nutrients are part of the ecology, while humans maintain the turf to their satisfaction.