PERILLO Gerardo Miguel E.
Coastal wetlands: an integrated ecosystem approach
Lugar: Amsterdam; Año: 2009 p. 941
Why coastal wetlands?What is so important about them that a whole book is requiredto try to review and explain their large variety of properties? Of all the coastal habitats,wetlands are the least depicted in the tourist brochures because they lack thoseparadisiacal long, white sandy beaches backed by palm trees or expensive resort hotelsclose to transparent blue waters. In fact, most coastal wetlands are quite muddy and aremore likely to be inhabited by crabs and worms than by charismatic fish, birds, andmammals. Hence, most inhabitants of our world either have never thought aboutcoastal wetlands or may consider them a nuisance, not realizing that their seafooddinner likely had its origin as a detrital food web in a salt marsh or mangrove swamp.Bahı´a Blanca (Argentina) inhabitants are a classical example: a city of over 300,000people living within 10km of a 2,300-km2 wetland, the largest of Argentina, butfewer than 40% have any idea that they are so close to the sea and a short distance ofplaces that are globally unique (Perillo and Iribarne, 2003, in chapter 14).Similarly, there are many other coastlines dominated by wetlands, yet they areonly seen as areas to exploit in an unsustainable fashion. For example, mangroveshave served local communities for generations in many Asian tropical countries forharvesting wood and fish in contrast to their wholesale replacement for ricecultivation and shrimp farming.Even though management guidelines have been available for decades, the negativeconsequences of uninformed exploitation have resulted in poor or even totallack of management criteria by most governments at all levels. Even local stakeholdersfail to act in their own best interest without consideration of the ecosystemgoods and services that the nearby wetlands provide.Coastal wetlands best develop along passive-margin coasts with low-gradientcoastal plains and wide continental shelves. The combination of low hydraulic energyand gentle slope provides an ideal setting for the wetland development. Also passivemargins are less prone to receive large episodic events like tsunamis. Tsunamis andstorm surges, in particular, are major coast modifiers, but when they act on low coaststheir effects are much far reaching than in higher relief coasts. For a wetland to form,there is need for a particular geomorphological setting such as an embayment orestuary providing relatively a low-energy environment favoring sediment settling,deposition, and preservation. However, that is only the beginning of a large andcomplex ‘‘life’’ where many geological (i.e., sediment supply, geological setting, andisostasy), physical (i.e., oceanographic, atmospheric, fluvial, groundwater processes,and sea level changes), chemical (i.e., nutrients, pollutants), biological (i.e., interveningflora and fauna), and anthropic factors play a wide spectra of roles. Coastalwetlands are areas that have combined physical sources and biological processes todevelop structure that continues to take advantage of natural energy inputs.This book has been planned to address in an integrated way all these processesand their consequences on the characterization and evolution of coastal wetlands.It aims to provide an integrated perspective on coastal wetlands as ecosystems forthe public, engineers, scientists, and resources managers. It is only after acquiringthis perspective that scientists can confidently propose ecohydrologic solutions formanaging these environments in an ecologically sustainable way. This is but onesmall step toward encouraging humanity to look beyond purely technological, andoften failed, solutions to complex environmental problems.This is done by focusing on the principal components considering the full range ofenvironments from freshwater to subtidal and from polar to tropical systems. Thebook has been divided into seven parts starting from a synthesis chapter that integratesthe whole book. Part II covers, in three chapters, the general description of thewetlands structured according to broad climatic regions and introduces the mostimportant physical processes that are common to all coastal wetlands including somegeomorphologic and modeling principles. Parts III–V are specific to each particulartype of wetland (tidal flats, marshes and sea grasses, and mangroves). Within each part,there are chapters dealing with their particular geomorphology, sedimentology,biology, and biogeochemistry. Finally Parts VI and VII provide insight into therestoration and management and sustainability and landscape dynamics.