Civilization depends on life-support services that natural ecosystems perform, including regulating climate, mitigating floods and drought, protecting shorelines from erosion, purifying air and water, detoxifying and decomposing wastes, and pollinating crops and natural vegetation. Healthy ecosystems provide habitat for diverse fish and wildlife communities. Studies conducted by USGS Terrestrial, Freshwater, and Marine Environments scientists describe factors that control ecosystem structure, function, condition, and the provision of goods and services. This information is used to predict future changes to ecosystems and to describe the results of management alternatives. Ecosystem science is thus used tomake and operate management plans to restore degraded landscapes and freshwater systems, sustain plants and animals, and find means to adapt management to global change