Swampy saviours

Wetlands have been an increasing focus of attention in recent years, not only from the scientific and conservation community but from other sectors of society. Recent floods have drawn public attention to the natural origin and valuable function of flood plains and wetlands throughout river catchments, which can substantially reduce downstream flooding. Repairing mistakes is expensive - the estimated cost of the plan to restore and protect the Florida Everglades is nearly $8 billion (£5.5 million). Despite their value, wetlands are some of the most abused ecosystems on the planet: in the past 15 years more than 1 million hectares of marshland have been drained in southern Iraq, destroying the unique Madan culture.

Why has science been so ineffective in arresting this demise? Arguably, the vast diversity of wetlands has contributed to the fragmentation of their study among different disciplines and to the lack of a forceful "wetland science". Paul Keddy sets out to provide "some unity and coherence in the study of wetland ecology". He draws on a wealth of ecological knowledge, much of it derived from his own empirical research, to consolidate an array of information linked to general theory and underlying principles. He does not confine himself to the results of wetlands research but draws on parallel findings from other habitats and ecosystems. Some may find the text self-indulgent and opinionated, but it will generate healthy argument among students, scientists and conservationists. The liberal use of figures and an excellent bibliography will provide the advanced undergraduate or researcher with a good starting point for further work.

Having explained the workings of "the ecological communities that occur where green meets blue", Keddy concludes with a discussion of conservation and management. He adopts elements of the more traditional approach to conservation based on criteria such as naturalness and representativeness as well as the increasingly important case based on maintaining functions (such as flood reduction and groundwater recharge).

But his most important factor for selecting priority wetlands for conservation is area, on the basis that all important ecological values increase with size. He contrasts the many small wetlands in Western Europe with the dearth of large wetlands such as those of the Pantanal, the Sudd and the Amazon, where much more ecological value is at stake amid growing human threats.

Keddy provides a background to the challenge of translating the science into the better decision making essential to maintain wetland resources. But his detailed treatment is of the much more controversial area of politics and human behaviour.

Keddy's ecological perspective sees human activities compressing wetlands into an ever-narrower range of flooding and fertility regions. Tackling wetland convergence requires a sound scientific understanding. Wetland Ecology contributes to this by providing a coherent analysis of the fundamentals that make wetlands what they are and what they might be. Implementing this knowledge requires radical changes in how we manage land, water and living resources as one integrated system rather than the sectoral areas favoured by government.

Edward Maltby is professor of environmental and physical geography, Royal Holloway, London.