ecotone

An ecotone is a transition zone between two or more ecological communities where the composition and structure of species change gradually or abruptly. It represents the area where environmental gradients and biotic interactions from adjoining ecosystems overlap, creating a distinct but interconnected habitat. The term encompasses boundaries between biomes, habitats, or land-use types and can vary in width across space and time.

Ecotones often harbor higher species richness and diversity of interactions than adjacent areas, due to the mixing of species from neighboring communities and the presence of edge-adapted organisms. Their characteristics depend on scale and the strength of underlying gradients, including light, moisture, soil nutrients, salinity, temperature, and disturbance regime. Edge effects, microclimate shifts, and nutrient flows contribute to unique community assemblages in ecotones.

Causes include natural succession, abrupt or gradual environmental change, climate gradients, and human disturbance such as fragmentation or land-use change. Examples include forest–grassland transitions, river or floodplain zones, salt marsh–mangrove interfaces, and alpine treeline–tundra zones. Ecotones can be dynamic, moving with seasonal cycles or long-term climate trends.

Ecotones are important for ecological processes such as dietary webs, pollination, seed dispersal, and habitat connectivity. They are used as indicators of environmental change and are considered priorities in conservation for maintaining landscape resilience. Researchers measure ecotones with transects or remote sensing to quantify boundary width, edge contrast, and species turnover.