Wetland Ecology: Principles and Conservation

Abstract

P. A. Keddy ( 2000 ) Wetland Ecology: Principles and Conservation. Pp. xiv + 614 . Cambridge University Press , Cambridge . ISBN 0-521-78001-2 . Price £90.00 (hardback). ISBN 0-521-78367-4. Price £32.95 (paperback). The title of this book has been carefully and well chosen. As well as encompassing its contents, it also excludes elements that might otherwise have been expected. This is not, per se , an account of the different types of wetlands found in the world, nor is it a region by region documentation of the distribution of wetland types. In many ways it seeks to perform a more challenging task than either of these; namely, to examine those ecological features that wetlands have in common, such as developmental processes, diversity variations, and responses to hydrology and nutrient conditions. In this respect it is a novel if not unique approach to wetlands. We cannot escape, however, the classification, the terminology, the jargon of wetlands, that could so easily occupy the entire volume. Keddy adopts an American terminology which will undoubtedly irritate European wetland ecologists who feel that their use of such terms as ‘marsh’ and ‘swamp’ have a greater antiquity (and therefore credibility) than that of the New World ecologists. Keddy is somewhat dismissive of European terminology and this even extends to his insistence that such well-established phrases as ‘Papyrus swamp’ should be given in quotation marks because these ‘swamps’ are not forested (which all American ‘swamps’, by definition, are). But it would be pedantic to judge this otherwise innovative and exciting book on such features. When we turn to principles, there is much here to stimulate thought. When considering the question of succession and zonation, for example, it is refreshing to find the two carefully distinguished. The ‘terrestrialization’ story so often repeated in wetland texts, is a gross over-simplification, if not fabrication, and it is pleasing to see this revealed here. Although sedimentary studies in the elucidation of succession pathways are mentioned, however, it would have been useful to see this line of evidence more fully exploited when examining the degree to which zonation may or may not reflect successional pathways. Why are some wetlands more biodiverse than others? Here is a question to exercise the mind. Bird diversity, for example, seems to follow structural (and temporal) diversity of habitat, but why, in that case, are mudflats so diverse in their avifauna? Intermediate stress, and species pool concepts are also examined in relation to the determination and control of diversity. Water levels and nutrient levels rank high among the determinants of wetland ecosystems and they are given a chapter each, as are disturbance and competition, all topics that lend themselves to examination within a wetland context. Burial, a rather colourful and emotive title for a chapter on sedimentation rates, is a subject that needs close attention in a book on wetland ecology. The rates of burial influence changing hydrology and hence vegetation; an understanding of burial is also crucial to wetland conservation and management. We are presented here with a succinct collation of work on sedimentation, including models of accumulation. There is also information on the ways in which animals and plants cope with sediment accretion. But rather surprisingly, there is no coverage of carbon storage in peatlands and its potential impact on the global carbon cycle. Given the current interest in mires as possible carbon sinks, it is a topic that one might have expected to encounter here. The second part of the book’s subtitle draws attention to the conservation of wetlands, and it is good to see this element incorporated into the ecological discussions throughout the text. The closing chapters draw this theme together and examine the principles of wetland management. Keddy considers both the priorities for action in conservation and the selection of indicators to monitor the impact of management techniques. He is at pains to confess the complexity of wetland ecosystems and the general lack of knowledge on which to base management proposals. This realistic modesty may be disconcerting, but it is also wise. The message of the book is clear; we need to understand the principles underlying the functioning of wetland ecosystems if we are to be able to predict the outcome of management actions. This is a unique book on wetland ecology. It draws upon many of the concepts and questions current in modern ecological research and brings them to bear upon these very distinctive ecosystems of waterlogged habitats. It is a book that every wetland ecologist should read thoughtfully.