Nonetheless, successional species alter the environment in ways the facilitate the arrival of later species. For example, after a fire or logging in Washington State's west-side conifer forests, the pioneer community is often dominated by shrubs that resprout from roots. Young trees have a difficult time starting under shrubs, and succession proceeds faster if the shrubs are removed. Logging and burning remove nitrogen from an area. These plants facilitate the entry of later arrivals by helping to replenish the N in the soil, but they also inhibit later arrivals by their occupation of space.
Succession also occurs on the substrates of aquatic systems where organisms compete for space.
The overall pattern of succession is similar to that of terrestrial plants, except that succession in aquatic communities tends to take place at a very rapid rate. As on land, there is a fairly predictable sequence from pioneer community, intermediate seral communities, and a climax community. In streams, flooding is a common type of disturbance. Flood waters scour the stream bottom in some places and deposit sediments in others. A study of a creek in Arizona found that, within a couple of months after severe floods, the stream had rapidly passed through several successional stages dominated by different algae species.