Stream and river ecosystems are classic examples of both ecotones and networks in landscape ecology.  Stream ecologists have quantified gradients of environmental conditions (e.g., temperature, humidity), aquatic and terrestrial community structure (e.g., vascular plants, invertebrates, amphibians), and ecological processes (e.g., nutrient uptake, delivery of organic matter) across land-water interfaces from headwaters to estuaries.  Streams and rivers provide examples of network phenomena that alter terrestrially-based views of species-area relationships.  Network perspectives also have modified and expanded the concept of patch dynamics and implications for biodiversity.  Geomorphologists and landscape ecologists have explored the underlying patterns and implications for processes in river networks and compared them to other phenomena with branching structure.  Globally, riparian ecotones exhibit extremely high diversity and are widely cited mechanisms for connectivity across world landscapes.  Riparian areas inherently provide elevational connectivity along river networks, providing a range of mechanisms for dispersal and refuge at landscape scales in the face of global climate change.  These ecotonal properties make riparian areas in river systems disproportionately important in landscape management strategies in global conservation and restoration ecology.