Bleuten, A. Sirin, E.
- Us and them : Muslim-Christian relations and cultural harmony in Australia.
- AIDS: Safety, Sexuality and Risk (Social Aspects of Aids)?
- Review on the natural conditions and anthropogenic threats of Wetlands in Ethiopian!
- IN ADDITION TO READING ONLINE, THIS TITLE IS AVAILABLE IN THESE FORMATS:.
- The Mirror Crackd from Side to Side (Miss Marple Mysteries, Book 9).
- About this book.
Lapshina Introduction. Peatland Distribution and Main Types. Main Features of Peatland Development. Main Features of Climate During the Holocene. Peat Accumulation Dynamics. China N. Wetzel deceased Dennis F. Verhoeven, Boudewijn Beltman, Dennis F. Whigham, Roland Bobbink 1. Historically, their high level of plant and animal especially bird diversity is perhaps the major reason why wetland protection has become a high priority worldwide, supported by international agreements, such as the Ramsar Convention and the International Convention of Biological Diversity Fig.
More recently, a number of goods and services provided specifically by wetland ecosystems have been identified that may even outweigh biodiversity in terms of their importance for human welfare and sustainable natural resource management worldwide. Wetlands, as transitional zones between land and water, provide a natural protection against extreme floods and storm surges. They may also store freshwater to be used for drinking-water preparation or for irrigation.
Wetlands bordering streams, rivers and lakes have a water quality enhancement function that is increasingly recognized.
As natural habitats for fish, riverine wetlands, shallow lakes and coastal wetlands have the potential to produce large fish stocks, which are exploited commercially in some regions but could be enhanced by restoring wetlands in degraded areas. Because wetlands often provide spawning habitats, their importance as a source of juvenile fish for large aquatic lakes and river channels should not be underestimated. In addition to these local and regional benefits, wetlands as a global resource provide a net sink of carbon dioxide. However, the large amounts of carbon that have accumulated historically in peatlands may be released as a result of drainage or excavation.
Wetlands do produce a striking variety of goods and services and it is no wonder that, more often than any other terrestrial ecosystem, they are used by Ecological Studies, Vol. Beltman, R. Bobbink, and D. Verhoeven et al. However, in spite of the high biodiversity and the high importance of the goods and services of wetland ecosystems, their global status is poor. Many wetlands, particularly river floodplains, deltas and estuaries, have been strongly degraded because of human impacts.
Early civilizations were particularly successful in these areas, where agriculture thrived because of the natural fertility of the soils and transport was favoured by the river channels. In the industrial era, these impacts became dramatically negative as a result of floodplain reclamation, poldering, construction of flood control structures, drainage for agriculture, excavation of peat for fuel and modification and straightening of river channels in favour of navigation.
This volume, containing an integrated account of a number of major symposia presented at the 7th INTECOL International Wetlands Conference in Utrecht, investigates the major natural resource management issues involved in the protection of the remaining wetland resource, the enhancement of the goods and services arising from this resource and the restoration of degraded wetlands and wetland functions.
In this introductory chapter, we will give an overview of recent advances in the comprehension of how both wetland biodiversity and the wetland ecosystem goods and services can be enhanced by management decisions, as treated in more detail in the other chapters of this volume.
We will also identify remaining gaps in scientific knowledge and understanding that need to be addressed to optimize the decision-making process on wetland land use and management. Access to healthy freshwater resources has even been identified as a fundamental human right. The relation between wetlands and the availability of freshwater recently led to confusion among natural resource managers.
This service would suggest that wetlands are sources of water and do not compete with other water-demanding sectors such as agriculture or water use for sanitation or industry. In this view, wetlands would even be potential sources of water. However, in reality, wetlands are as much dependent on water as these other sectors. Being systems with a high water table, they can only maintain their characteristic biota and functioning if Wetland Functioning in a Changing World Fig.
The water lotus is a typical wetland plant with aerenchyma 3 4 J. Most wetland types require inputs of surface water or groundwater in addition to the inflow through precipitation. In practice, wetlands often compete for water with agriculture or drinking-water preparation, in particular in semi-arid regions. A first example is the use of water in many sub tropical countries for irrigation, which has led to the drying-out of vast wetland resources. The water used for irrigation, mostly present as soil moisture, also leads to a major regional water loss which is equal to the amount of water evapotranspired by the crops.
A second example of a controversy on the uses of limited water resources is the situation in the Everglades, Florida. Here, a large freshwater surface resource flowing over the land surface south of Lake Okeechobee is used increasingly for urban, agricultural and industrial purposes by the metropolitan region surrounding Miami.
As a result, the large wilderness area of the Everglades wetlands see Fig. Everglades National Park , is suffering from water shortage and is threatened on the longer term. It remains to be seen whether this will provide a sustainable solution to the protection of the Everglades and its many biota and other values. The idea is that so much water in river systems is diverted and used for agriculture, cities or industry that rivers can no longer function naturally.
River flow and flood events are increasingly limited to a narrow zone bordering the river channel, while the lateral interactions with the often extensive floodplains become diminished. This has drastic negative consequences for the biota characteristic for floodplains and for the goods and services provided by the floodplain habitat. Restoration of lateral Wetland Functioning in a Changing World 5 connectivity by bringing floodwater only to selected parts of the original floodplain may help in restoring the intensity and temporal dynamics of typical flooding events, rather than allowing the water to create too small a flooding event in the total floodplain.
The Solutions Journal
This is illustrated for rivers in Australia by Coops et al. Chapter 2 and for tropical rivers by Welcomme et al. Chapter 7. The EF concept is in the stage of becoming widely accepted among water resource managers as a tool to maximize the quality of biodiversity restoration and associated fisheries in large river floodplains with diminished river discharge. Some of the projects described in Chapter 2 illustrate the successful restoration of floodplain habitats in the basins of the rivers Rhine, Rhone and Danube.
A recent review gives a global perspective of this ecosystem service in areas of the world with high intensity of agricultural use Verhoeven et al. Riparian wetlands bordering lower-order streams and floodplains of mid-size and larger rivers have a great potential to remove nutrients and pollutants from through-flowing water. Nitrate in surface and subsurface runoff from agricultural fields and pastures, when exposed to superficial soil layers in the riparian zone, is transferred to gaseous nitrogen species and emitted to the atmosphere, while phosphate and ammonium are retained in vegetation or bacterial biomass, adsorbed to soil particles or laid down in sediments.
Long-term loading of these zones, however, enriches these riparian wetlands, which often leads to the loss of characteristic species. Critical loading rates for N and P have been established for freshwater wetlands, beyond which losses of plant and animal species are to be expected. Riparian zones have also been shown to be only effective at the catchment scale if they are sufficiently large and continuous in the landscape.
Ebook Wetlands And Natural Resource Management (Ecological Studies, )
Wetlands restoration schemes in agricultural areas should take into account these limitations. The chapter by Yin et al. Chapter 4 deals with a rural system for water resources management which has been developed in the southern part of China. Another example of the pivotal role of natural wetlands in this respect is given by Loiselle et al. Chapter 6 for the extensive papyrus wetlands around Lake Victoria in Africa. These wetlands are enormously important to halt the eutrophication of the large lake. Many local communities around the lake depend on the fisheries as their main source of protein.
In addition to the nutrient removal service, these wetlands provide a number of other important goods and services, such as papyrus stems, protection from damage by storm surges and a habitat for juvenile fish.
Wetlands Values and Trends
Another application of the water quality enhancement service of wetland ecosystems is the construction of wetlands just for this purpose. Vymazal et al. Chapter 5 give a thorough review of the latest knowledge on the performance, efficacy and application of different kinds of constructed wetlands. An example of such a system is a combination of a vertical-flow wetland, in which organic matter is broken down and nitrification can take place, followed by a horizontal-flow wetland in which denitrification reduces the N content of the water.
In almost all cases, constructed wetlands form an inexpensive and sustainable alternative to more technological solutions which require higher energy inputs and more expensive investments. A disadvantage of constructed wetlands is that they emit relatively high quantities of the greenhouse gases nitrous oxide and methane. This is particularly true for highly nutrient-loaded wetlands, which mostly have only a limited surface.
Better understanding of the factors controlling emission rates of these gases may give additional guidelines for the management of these systems. The high water table near the soil surface and the temporal patterns of water level fluctuations create many redox gradients in space and time, which leads to complex interactions among plants, microbes and geochemical processes. Redox cycles are often driven by the activity of aerobic and anaerobic bacteria and by the availability of alternative electron acceptors such as nitrate, iron, manganese, sulphate and carbon dioxide.
Further, wetland plants have aerenchyma, a system of air-filled cavities bringing oxygen to the roots and rhizomes Fig.
Oxygen leaks into the rhizosphere to a certain degree. Recent studies have focused on the role of bacteria in wetland rhizospheres. Bodelier et al. Chapter 10 give a fascinating overview of recent results in this field. New molecular methodologies such as micro-array technology have enabled estimations of the diversity of various functional groups of bacteria.
Large differences in diversity were found. Diazotrophic microbes, which are capable of fixing atmospheric nitrogen, show a remarkable high diversity in wetland rhizosphere systems.