Riparian Zones

Abstract

Riparian ecosystems are among the most diverse terrestrial ecosystems on all continents on Earth. Geologic and ecoregional setting, the form and distribution of water and sediment supply, connectivity, and the regional species pool govern the physical form, the seasonal and interannual flow and sediment regime, together define the possibilities and constraints on riparian biota. Presence, population structure, community composition, ecological characteristics and ecosystem services of riparian ecosystems are governed by the seasonal and interannual availability of water. Riparian ecosystems vary longitudinally, along a river's course from headwaters to terminus, and laterally from the channel to the uplands, often exhibiting distinctive zonation of vegetation. The complex microhabitats that form along waterways result in diverse range of vegetation types that can result in mosaics of vegetation that provide resources and habitats for resident and migratory wildlife. Threats to the functioning of rivers and riparian areas and the wildlife that they support are intensifying as climate change alters the Earth's hydrologic cycle and land cover, and as human populations continue to develop rivers and further alter hydrologic and sediment regimes around the world. The riparian science, river conservation and restoration have advanced in recent decades and include legal protections for rivers, restoration of flow regimes and functions, dam removal and active and passive riparian restoration.