Multifunctional Wetlands

Abstract

Natural wetlands are complex ecological systems that incorporate physical, biologi- cal and chemical processes. These wetlands play an important role in protecting freshwater and marine ecosystems from excessive inputs of nutrients, pathogens, silt, oxygen demand, metals, organics and suspended solids, as well as providing a buffer against storms, soil stabilization and wildlife habitat (Sierszen et al. 2012; Zedler and Kercher 2005; Engelhardt and Ritchie 2002). Attempts have been made to quantify the economic benefits of these ecological systems (Woodward and Wui 2001; Barbier et al. 1997), but it is also recognized that natural wetlands have cul- tural value (Papayannis and Pritchard 2008). The Convention on Wetlands of International Importance, commonly known as the Ramsar Convention, held in 1971 established a global framework for conservation of natural wetlands. Estimates of the area of wetland ecosystems on a global scale vary from 917 million hectares (Lehner and Doll 2004) to more than 1270 million hectares (Finlayson and Spiers 1999).