I'm more into the social side of SESs, mostly because I am not a biologist and my education/interest is in the social sciences. That's an aside, however, so I'll keep it simple and general here. The two most interesting things are the "adaptive cycle" model and the associated "panarchy" system of linked, multiscaled adaptive cycles. It is these models that explain the life cycle of systems from ecosytems to global financial systems. In the adaptive cycle, very basically stated, a system start simple, get evermore complex and larger at it grows, reach a point where it cannot sustain itself, and then collapses (due to some random event) and reorganises into some new system(s) and repeats the process. An example you might easily connect with is Iraq. Prior to 2003 Iraq was a complex, stressed but fairly stable state (a system). The US invasion collapsed that system, and the country is brutally reorganising itself along new lines, with thousands of new cycles of collapse and renewal taking place across Iraq as it finds itself a new stable state. A big easy one would be the evolution of life on Earth from wee one-celled bits of organism in primordial sea, to the diverse planet we live on now, with the great adaptive cycle collapsed a few times around the extinction of the dinosaurs, and possibly soon global warming. Generally speaking, the more resilient a system is, the simpler and more adaptable it is. It gets a little more complicated than this, but I hope you get the basic picture. The model of the cycle (you'll see it if you follow the links) looks like an infinity symbol.
Ecosystem resilience is the capacity of an ecosystem to tolerate disturbance without collapsing into a qualitatively different state that is controlled by a different set of processes. A resilient ecosystem can withstand shocks and rebuild itself when necessary. Resilience in social systems has the added capacity of humans to anticipate and plan for the future. Humans are part of the natural world. We depend on ecological systems for our survival and we continuously impact the ecosystems in which we live from the local to global scale. Resilience is a property of these linked social-ecological systems (SES). "Resilience" as applied to ecosystems, or to integrated systems of people and the natural environment, has three defining characteristics:
- The amount of change the system can undergo and still retain the same controls on function and structure
- The degree to which the system is capable of self-organization
- The ability to build and increase the capacity for learning and adaptation
The geek in me sees resilience as a great way to look sustainability for two reasons. First, it provides a model to help us develop better ways of living on the Earth. And second, it is optimistic. Things get bad, then they get better, we just have to be adaptable enough to do it. And life goes on..errr..hopefully with human life and civilisation still intact. A bit of optimism can't hurt us these days.
It may also be of interest to know that Dr. CS "Buzz" Holling, the key founder of the theory, is Canadian.
The resilience research group's website is definitely worth exploring if you're keen. They have a blog as well, linked on the right-hand side of the main website. Also linked is their free access multidisciplinary journal - Ecology & Society. Thomas Homer-Dixon bases his latest book around the concept, making it very accessible to the general public (good starting point), while dressing it up with his own spin and new fangled noun (he's not as original as he thinks he is but that's another story). A more scholarly introduction can found here. Enjoy.