Economic and social systems are sub-systems of the global environment; sustainability in the economic and social spheres is subordinate to sustainability of the environment. Development, from the ecological viewpoint, is seen to refer to the “capacity of [an ecosystem] to respond positively to change and opportunity” or the “maintenance of [ecosystems’] dynamic capacity to respond adaptively” (Golley, 1990). The key property to be sustained then is the capacity of ecosystems to respond with resilience to external perturbations and changes.