The role of ecotones (transition zones) in the conservation and management of tropical inland waters

Abstract

All inland water bodies are an integral part of their drainage basins. Most tropical water bodies are shallow and experience large water-level changes. The marginal zones of lentic waters and the floodplains and banks of rivers and streams therefore represent a wide transition zone (or ecotone) between uplands and open water. Since most of the water, silt, nutrients and organic inputs from the catchment must pass through this transition zone before reaching the water body, the biota of this zone and the ecosystem processes operating therein play a significant role in regulating the water quality, biodiversity and productivity of inland waters. During the past few decades, shoreline modification of inland waters for different reasons (flood control, flow regulation, land reclamation, etc.) have reduced greatly the extent of transition zones (= ecotonal area) between land and water, with consequent degradation of water quality. This paper discusses the ecotone concept as applied to land-water interfaces, and highlights important characteristics and functions of ecotones. Attention is drawn to the relevance and importance of ecotones to the conservation and managenent of tropical inland waters, under-scoring the need for investigations of ecosystem processes in these zones.