Lake Chilwa

Leonard C. Beadle In contrast to the more sta bie oceans, inland waters are, on the geological time scale, short-lived and are subject to great fluctuations in chemical composition and physical features. Very few lakes and rivers have existed continuously for more than a million years, and the life of the majority is to be measured in thousands or less. Earth movements, erosion and long-term climatic changes in the past have caused many of them to appear and disappear. No wonder then that most freshwater organism are especially adapted to great changes and many even to temporary extinction of their environment. Recent studies of residual sediments from existing and extinct lakes in tropical Africa have told us much about their age and the past history of their faunas and floras, from which we may deduce something about the climate and the conditions in the water in the past. The forces that have formed and moulded the African Great Lakes have been catastrophic in their violence and effects. They are not yet finished, but the present rate of change is, in human terms, too slow for direct observation of the ecological effects. The large man-made lakes are providing very good opportunities for studying the chemi cal and biological consequences of the initial filling but, once filled, they are artificially protected against major fluctuations.

This book is the outcome of a major international conference on waterbirds held in Edinburgh in April 2004.

Interest in the biology of African 'wetlands' was initiated in the last century with the hypothesis that Lake Tanganyika was once part of a Jurassic sea, and was furthered by Cunnington's expedition at the beginning of this century which proved that it was not. In the late 1920's, ecological studies, encouraged by the growing importance of inland fisheries, were started hy British, French and Belgian biologists. Some twenty years later several government limnological research centres and fishery departments were established in tropical Africa, and scientific progress was accelerated. Scientific collaboration between the regions south of the Sahara was started formally in 1951 by the Scientific Council for Africa and stimulated by the International Biological Programme (1964-74) with its emphasis on biological productivity. Some of its interests were takcn on by SCOPE which recently selected continental wetlands as a Special Project; hence this book. The five authors, with-Patrick Denny as editor, have made a very valuable contribution both to science and to thc management of Africa's natural rcsourccs: thcy have filled a gap in the synthesis of knowledge about Africa's environments which is long overdue. The term 'wetland' is used today in several different contexts. For this purpose, it excludes the seas and large open inland waters. which are too deep for rooted plants, but includes the huge areas of floodplains and dambos which may change seasonally from standing water to very dry lands.

In 2000, various UN organizations launched a collaborative effort to assess the vulnerability of groundwater in several African cities. The project addressed the issue of aquifer vulnerability and the protection of groundwater quality. This book is a collection of thirty peer-reviewed papers on the topic, and provides a glimpse of the situation acr

In this book the authors argue for a paradigm shift in the way African wetlands are considered. Current policies and wetland management are too frequently underpinned by a perspective that views agriculture simply as a threat and disregards its important contribution to livelihoods. In rural areas where people are entrenched in poverty, wetlands (in particular wetland agriculture) have a critical role to play in supporting and developing peoples' livelihoods. Furthermore, as populations rise and climate change takes grip they will be increasingly important. The authors argue that an approach to wetland management that is much more people focused is required. That is an approach that instead of being concerned primarily with environmental outcomes is centred on livelihood outcomes supported by the sustainable use of natural wetland resources. The authors stress the need for Integrated Water Resource Management and landscape approaches to ensure sustainable use of wetlands throughout a river catchment and the need for wetland management interventions to engage with a wide range of stakeholders. They also assess the feasibility of creating incentives and value in wetlands to support sustainable use. Drawing on nine empirical case studies, this book highlights the different ways in which sustainable use of wetlands has been sought, each case focusing on specific issues about wetlands, agriculture and livelihoods.