zonatsioon

Zonatsioon, or zonation, is the systematic arrangement of organisms or ecological communities into distinct zones along a gradient of environmental factors. It describes how species composition changes across space, producing recognizable bands with different biotic communities.

The pattern arises from variation in abiotic conditions such as moisture, temperature, salinity, light, nutrient availability, and physical context (for example altitude, depth, or exposure). Species interactions, including competition, predation, and ecological succession, as well as physical barriers and disturbances, can reinforce and maintain zonation.

Common examples appear across ecosystems. In coastal areas, intertidal zonation creates bands such as supralittoral, splash, high tide, middle tide, and low tide zones, driven by wave action and desiccation. Mountainous regions show vegetation belts that shift with altitude, from forests to alpine meadows and bare rock. In lakes and rivers, depth-dependent zonation yields littoral, limnetic, profundal, and benthic zones. Soils can also exhibit zonation, where moisture, chemical gradients, and horizon development influence plant and microbial communities.

In scientific usage, zonation is a descriptive term in ecology, biogeography, and related fields. In human geography and urban planning, the word can refer to deliberate zoning of land use (residential, commercial, industrial) as a policy instrument. While related in concept, natural zonation and human land-use zoning describe different processes and aims.