zonation
1. The broad distribution of vegetation according to latitude and altitude. The control is primarily climatic, and similar vegetation zones are encountered on the flanks of high tropical mountains to those found at sea level between the tropics and the poles.

2. The division of an ecosystem into distinct vertical layers that experience particular abiotic conditions. This is particularly clear in the distribution of plants and animals on a rocky seashore, where different species inhabit a series of horizontal strips or belts of the shore, approximately parallel to the water's edge. In many places the strips (zones) are sharply bounded by the differently coloured seaweeds that populate them.

3. The division of vegetation in relation to a successional sequence (e.g. in sand-dunes), implying that spatial zonation may correspond to temporal processes. This assumption, which may be flawed, is often used as the basis for succession studies.

zonation
1. The broad distribution of vegetation according to latitude and altitude. The control is primarily climatic, and similar vegetation zones are encountered on the flanks of high tropical mountains to those found at sea-level between the tropics and the poles
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2. The division of an ecosystem into distinct vertical layers that experience particular abiotic conditions. This is particularly clear in the distribution of plants and animals on a rocky seashore, where different species inhabit a series of horizontal strips or belts of the shore, approximately parallel to the water's edge. In many places the strips (zones) are sharply bounded by the differently coloured seaweeds that populate them.

zonation The distribution of the different species of a community into separate zones, which are created by variations in the environment. A clear example of zonation occurs on a rocky shore, where different species of seaweed (Fucus) occupy different zones, according to their ability to withstand desiccation. For example, the species found in the splash zone, which is never completely submerged in water, is better adapted to exposure than those found in zones lower down the shore, where they are submerged for longer periods. Animals, particularly stationary species, such as barnacles, also exhibit zonation on a rocky shore; as with the seaweeds, this may depend on the ability of different species to withstand desiccation. Competition between species may also contribute to zonation.

zonation The spatial distribution of species at any one time according to variations in the physical environment (e.g. the distribution of seaweeds and marine animals between the low-tide and hightide marks on a rocky shore, and the vertical distribution of species on a mountainside).

zonation The subdivision of a stratigraphic unit or units by means of fossils.