Ecotones, or boundary zones between land and inland waters (such as lakes, streams and rivers), are the principal routes for transport of organic matter and nutrients across landscapes via physical and biological vectors. The ecotone is the place of cumulation and transformation of in situ production as well as of allochthonous material from adjacent aquatic and terrestrial systems. The ecotype functions as an important barrier or filter for principal nutrients, such as phosphorus and nitrogen, responsible for the eutrophication and degradation of surface waters. Intensive forest cutting, agriculture, pollution and bank regulation, urbanization and hydrotechnical constructions seriously endanger the ecotone systems and damage their protective function. It is vital to develop a scientific understanding of the behaviour of phosphorus and nitrogen in these transitional boundary habitats. Such an understanding is important for the rational protection, management and restoration of ecotones connected with lakes and rivers. The importance of nutrient cycling and retention is discussed from the point of view of ecotone function, management and reconstruction in order to sustain its protective role for water bodies. Various types of land/water transitory zones are discussed: wetlands, lake littoral systems, riparian zones of rivers, streams and brooks, the contact zones between groundwater and surface waters of lakes and rivers, air--water interfaces, and patch/ecotone structures in watersheds.

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Wetlands, lake littoral zones.- Seasonal nitrogen dynamics in reed beds (Phragmites australis. (Cav.)Trin. ex. Steudel) in relation to productivity.- Growth and nutrient uptake by two species of Elodea in experimental conditions and their role in nutrient accumulation in a macrophyte-dominated lake.- Macrophyte-related shifts in the nitrogen and phosphorus contents of the different trophic levels in a biomanipulated shallow lake.- Functioning of land-water ecotones in relation to nutrient cycling.- Some considerations on the functioning of tropical riparian ecotones.- Nitrogen and phosphorus dynamics and retention in ecotones of Lake Titicaca, Bolivia/Peru.- Detritus and nutrient dynamics in the shore zone of lakes: a review.- Microbial decomposition of freshwater macrophytes in the littoral zones of lakes.- Frost formation in the ecotonal zone and its role for release of nutrients.- Effect of filtering activity of Dreissena polymorpha (Pall.) on the nutrient budget of the littoral of Lake Mik?oajskie.- The role of small mammals and birds in transport of matter through the shore zone of lakes.- Streams, rivers, riparian vegetation.- Transport and retention of matter in riparian ecotones.- Nitrate transformation and water movement in a wetland area.- Retention of nitrogen in small streams artificially polluted with nitrate.- Retention of nitrogen and phosphorus in a Danish lowland river system: implications for the export from the watershed.- Flow and retention of particulate organic matter in riparian fluvial habitats under different climates.- Importance of flood zones for nitrogen and phosphorus dynamics in the Danube Delta.- The Vistula river and its riparian zones.- Hydrological problems of the Vistula river valley near P?ock.- Groundwater-surface water ecotones,air-water interface.- The role of water exchange between a stream channel and its hyporheic zone in nitrogen cycling at the terrestrial-aquatic interface.- Nutrient and flow vector dynamics and the hyporheic/groundwater interface and their effects on the interstitial fauna.- Storage and dynamics of organic matter in different springs of small floodplain streams.- Transport of groundwater-borne phosphorus to Lake Bysjön, South Sweden.- Role of aquatic surface microlayer in the dynamics of nutrients and organic compounds in lakes, with implications for their ecotones.- Patch/ecotone pattern in watershed, lake-river systems.- The shore vegetation in selected lakeland areas in northeastern Poland.- Energy control of matter fluxes through land-water ecotones in an agricultural landscape.- Role of meadow strips for migration of dissolved organic compounds and heavy metals with groundwater.- The dynamics and retention of phosphorus in lentic and lotic patches of river-lake systems.- Particulate phosphorus sedimentation at the river inflow to a lake.- Patterns of spatial distribution of phosphorus regeneration by zooplankton in a river-lake transitory zone.- Drainage history and land use pattern of a Swedish river system - their importance for understanding nitrogen and phosphorus load.- Impact on lake development of changed agricultural watershed exploitation during the last three centuries.- Ecotone recovery and management.- Nutrient retention of the Kis-Balaton Water Protection System.- A multi-pond system as a protective zone for the management of lakes in China.- Management of land/inland water ecotones: needs for regional approaches to achieve sustainable ecological systems.- The application of the ecotone concept in defining nutrient management requirements for theupper Potomac River basin.- Modelling the effects of alternative nutrient control policies - the example of Slapton Ley, Devon, UK.