Riparian Wetlands of Tropical Streams

Riparian wetlands are temporarily or permanently inundated and/or water-logged zones along the margins of streams and rivers. They link permanent aquatic habitats with upland terrestrial habitats, and surface-water with groundwater. This chapter focuses on riparian wetlands associated with low-order tropical streams, which have been lesser studied than equivalent ecotones associated with large rivers. We demonstrate that (a) these wetlands provide valuable habitats for diverse and highly specialized flora and fauna; (b) these serve as important longitudinal and transversal corridors for exchange of material and dispersal of biota; and (c) these perform important ecosystem functions locally as well as at the catchment scale. For example, headwater wetlands are key sites for mutual subsidies between terrestrial and aquatic systems, and are pivotal areas for the transformation of nutrients and organic matter. All riparian wetlands are subject to significant modification by humans, which compromises their functional integrity. However, riparian ecotones along loworder streams often occupy limited areas beyond the banks, and awareness of their ecological importance is limited in comparison to the extensive wetlands and floodplains associated with large lowland rivers. Creating awareness of the need for their sustainable management will be a challenging task.