Many plant communities gradually change with time, and the way in which one set of plants follows another is known as succession.

The first stage in a succession is known as a pioneer community. For example, there are relatively few plants that are able to live under the dry conditions of unstable sand dunes. Marram grass is often the only plant found growing in such places. The roots of this pioneer plant bind the sand together. As the sand dunes become more stable, other plants, such as heather, follow the marram, and provide a more complete plant cover. This heathland community will in its turn be invaded by shrubs and bushes (such as birch) and ultimately woodland will form.  The whole process may take several hundred years.

The animal communities change along with the plants. Relatively few insects or other animals are able to live amidst the open sand dunes. Many more types inhabit the heathland that follows the dune community, and the woodland may support a great variety of insects, spiders, birds and other creatures.

Sometimes there is a series of sand dune ridges along a coast, each of a different age. The ridge nearest the sea will have been blown there by the wind most recently and is likely to support a pioneer community. Those a little inland will be clothed with heath, scrub or woodland. Parallel sets of dunes of this nature exist on the Lancashire coast near Formby and at Studland Heath in Dorset.

Changes also occur in a stretch of open water. When a pool first appears - for example, when a gravel-pit is worked out and abandoned - water plants such as duckweeds, Canadian pondweed and water lily are the first to establish themselves. As time passes, however, silt is brought in from outside the pool and dead plant material accumulates on the pond bottom, so that the pool gradually gets shallower. Reeds then invade round the edges, and in time the entire pool will become overwhelmed by reedswamp. Eventually the whole depression is filled with dark peat - dead plant material.

A Carr, or low tangled woodland with willow and buckthorn, follows the reedswamp community, and if the area continues to remain undisturbed, tall oak or ash woodland often represents the last stage in the succession.

Very frequently, however, a succession is not allowed to follow its full natural course. For example, a patch of open water may be dredged before the filling-in process is complete or, as in the Norfolk Broads area of East Anglia, the reedbeds may be cut as a source of reed for thatching.