Biodiversity is an important component of the environment. A general rule of thumb is that the higher the biodiversity in a given local environment, the more sustainable it is. The ecosystem is the set of relationships among different components of the environment; it includes non-biological components.
Two different ecosystems are increasingly common in the United States: urban and suburban.
Urban environments have ecosystems that include high population density, which stresses the environment through overconsumption of resources and the reduction of green space. With a city's concrete and asphalt, fewer species are likely to thrive. Among the ways to increase the diminished urban biodiversity are restoring green space, such as through creating numerous "pocket parks," and planting and caring for trees—both a large number and more varied species, which will in turn attract more kinds of birds.
In the suburbs, clear-cutting to create empty spaces on which to construct housing developments is a trend that reduces biodiversity. Increasingly, developers are leaving a percentage of older trees and incorporating them into the community design rather than removing every tree. A diversified landscaping plan is also more beneficial to overall biodiversity than using a single plant. This approach is most obvious in the move away from the pristine green velvet expanse of lawn that became standard in late-twentieth-century suburbia. Maintaining a weed-free lawn also depends on using large amounts of water and chemicals together with application of herbicides, which are harmful to the water and to animals. Along with the lawn, non-native species, such as most roses, also disturb the natural ecosystem and often require chemical inputs. The "lose your lawn" movement is gaining strength. Rather than a lawn, a green space with a variety of native grasses and pollinator-attracting wildflowers is more conducive to biodiversity.