Disturbances affect ecosystems in almost limitless ways. The effects of disturbances extend beyond the initial impacts that are usually visible to the human eye. Therefore, for many disturbances long-term data are needed to unravel their effects.  This chapter first presents characteristics of disturbances for each of four major classes of disturbance: climatic, physical, biotic, and anthropogenic.  It then discusses ecosystem responses by disturbance class.  For climatic disturbances, ecosystem responses to hurricanes, drought, and global warming are discussed; for physical disturbances, wildfire on land and wave height in ocean; for biotic disturbance, herbivores feeding on lower tropic levels, invasive species, and a plant disease; for anthropogenic disturbance, changes in land use patterns.  These long-term records of ecosystem responses to disturbance illustrate the complexity of disturbance effects. Ecosystem responses are influenced by multiple disturbances and interactions with other factors, which make it very difficult to attribute cause and effect. Clearly large-scale, multiple-site experiments are needed to further unravel the relationships between particular disturbance events and ecosystem responses.