ABSTRACT
Sustainability borrows from observing biological systems. What nature does to combat instability in a particular environment evolves an integrated or linked diversity in which many species, at all scales, are connected through flows and cycles. Rivers are designed to flood without doing harm. Their banks are lined with trees that prevent erosion. Their immediate low-lying areas or flood plains are populated with plants and animals adapted to thrive on occasional floods. Those places where two kinds of natural systems come together—for example, where forest meets grassland or where tidal waters meet land—are called ecotones, and they are typically places of maximum biological diversity and productivity, and they are constantly changing yet maintain relative stability. Processes built upon a complex interlinked diversity—that's what sustainability is all about. We can apply the same criteria to guiding the future design of buildings and cities.
