Introduction

Wetlands are undoubtedly one of the most astonishing ecosystems across the Earth. They are present in almost every latitude zone, from the tundra to the equator in the tropic zone. Wetlands encompass several kinds of surfaces including the typical swamps, marshes, fens, bogs and others. Often perceived as dangerous sources of diseases like malaria, considerable wetland areas have been destroyed throughout history and with evident acceleration during the XXth century. This happened to both inland (freshwater) wetlands (Fig. I.1-1 and Fig. I.1-2) as well as to coastal or salty marshes, such as the tropical mangrove swamps (mainly brackish water).