- Email: [email protected]
Global Seagrass Research Methods
Book reviews
405
one weakness of this book is the limited number of references cited. This makes it difficult for the reader to go back to the original reference to examine the results in more details. This is likely an editorial decision aimed at preserving the appeal of this book for a wider audience. However, the information presented is generally detailed and accurate enough to provide the reader with a good overview or a starting point when documenting a topic. I have kept my copy of French edition close at hand since 2000 since I frequently had to refer to it for research and teaching purposes. Translated in English, this book has become even more useful to me. The French-to-English translation is very good. The translation conveys the more literary writing style used by most French authors. This makes the reading a little less dry than is commonly the case with many English language textbooks. The only negative point is that, in some cases, literal translation of French terminology and abbreviations is used instead of more widely used and accepted English terms and abbreviations. In conclusion, this book is an excellent reference book, a worth buy for all readers interested in fish and crustacean nutrition. This book would be a very useful companion textbook for undergraduate fish nutrition and aquaculture courses. Dominique P. Bureau Fish Nutrition Research Laboratory, Department of Animal and Poultry Science, University of Guelph, Guelph, ON, Canada N1G 2W1 E-mail address: [email protected] Tel.: +1-519-8244120x6688; fax: +1-519-767-0573 PII: S 0 0 4 4 - 8 4 8 6 ( 0 2 ) 0 0 2 6 1 - 2
Global Seagrass Research Methods F.T. Short and R.G. Coles (eds.). Elsevier, Amsterdam. (2001). 482 pp., Price EUR 174.71; USD 189.50, ISBN 0-444-50891-0 A new book on seagrass research methods. To satisfy my curiosity, the first thing I did was checking the book on its usefulness regarding the solution to minor practical problems I experienced myself in the course of the years. How do we quantitatively remove sediment from the seagrass root system? Page 149: ‘‘At the laboratory, clean both aboveand belowground samples of any remaining sediment. . .by rinsing the samples with seawater.’’ Next question: How do we sample seagrass epiphytes in a quantitative way, especially the calcareous ones? Page 149: ‘‘Plant samples are scraped free of epiphytes using a razor blade or glass microscope slide’’ Page 201 –202: ‘‘Epiphytes scraped from all leaves in a quadrate (0.2 0.2 m) may be bulked. . .’’. Page 213: ‘‘Place samples in a dilute solution of 5% nitric or hydrochloric acid until bubbles are no longer produced. Wash the epiphyte sample in distilled water to remove the acid before weighing.’’ That’s it, nothing has changed since 1990, but every experienced seagrass worker knows that these recipes do not provide us with quantitative data. On second thought, this is no doubt a thorough and informative volume on research methods dealing with one of the most productive coastal habitats, which has become
406
Book reviews
increasingly recognised over the last 35 years. The book is carefully produced, it contains excellent colour photographs, and a series of nice new diagrams. The format of the paragraphs is consistent; it starts with an introduction, followed by the objectives, then necessary materials and equipment, then methods, ending with a section on troubleshooting and hints, followed by a discussion. Particularly, the ‘troubleshooting and hints’ part is very instructive. Besides Fred Short and Robert Coles as editors, Catherine A. Short is mentioned as technical editor. To my opinion, she deserves the full honour of being coeditor of this volume. The editors assembled 51 authors from around the world, but the choice of the authors is biased, as the NE Atlantic and Mediterranean researchers are highly underrepresented. The editors asked the authors to display the most globally useful techniques, not necessarily the newest ones or those requiring equipment available only to the economically privileged. That is of itself a commendable ambition, but requiring access to a DNA analysis laboratory (Ingliss) and to the ‘relatively expensive’ (p. 196) PAM fluorometry (Beer) is not directly illustrative of this approach. The book is organised into three sections. The first section covers the current world distribution of seagrasses; it further provides identification keys and descriptions, and details on reproduction and phenology. This is a useful and compact section. It is reminiscent of an abridged update of Den Hartog’s (1970) famous monograph ‘Seagrasses of the World’, but the (scanty) drawings are too small and unclear (e.g. 1.7 and 3.1), and detailed distribution maps are lacking. Section II covers the main content of the book: a global set of methods for seagrass environments, starting with general sampling and collection procedures and statistical issues, followed by an analysis and presentation of information on spatial data distribution, such as mapping and remote sensing. These are originally arranged and very interesting chapters. The next group of chapters focuses on the plants themselves: seeds and genetics, abundance and distribution, growth and photosynthesis. Methods for the measurement of these aspects of seagrasses represent the basic range of parameters fundamental to most seagrass studies. The book continues with methods for measuring algae and animals associated to the seagrass ecosystem, followed by methods to study grazing and decomposition. The section ends with a display of methods to quantify physical and chemical variables that regulate plant and animal activities and are determinants of seagrass distribution. No doubt, all chapters contain important information, but notwithstanding the rather consequent consistency in the format, the content of the papers is inconsistent (see, e.g. my appreciation of chapter 8 versus chapters 9 and 16). But this is probably due to the fact that so many different authors have contributed to the book. Particularly, a multi-author book on methodology needs more consistency in the presentation as regards content of the different techniques, and less overlap in statistical treatments. My suggestion is to combine all statistical methods in one chapter, with cross-references to the other chapters, because now there is quite some redundancy in the explanation and the use of PCA, CCA, ANOVA and other statistical treatments. Chapter 8 (growth and production ) gives an excellent description of direct seagrass growth measurements methods, especially the leaf and rhizome marking method. Step by step, the methodology and the protocols are explained. My only comment concerns the fact that the plastochrone method should have been described in a more critical context. The hint in the sampling protocol is illustrative of the lack of that approach: ‘Select a
Book reviews
407
station for growth measurements; areas with broken or grazed leaf tips should be avoided’ (p.167). Broken and fully epiphytized leaves demonstrate often signs of habitat deterioration. Particularly, in these spots it is very important to know whether the seagrass is able to survive (positive net primary production signal) or will die off (negative production signal)—see also Section III. Chapter 9 (photosynthesis) is disappointing; it is rather an incomplete review than a detailed description of research methods. What about the use of microelectrodes measuring oxygen microprofiles in the sediment, as early warning signals of habitat deterioration (see my comment referring to Section III)? Not a word on community metabolism measurements, in the proper set up showing oxygen signals of all plant and animal components in the enclosure. Not a positive word on the use of radioisotopes (‘not recommended’ p. 184), although the two methods (oxygen and radioactive carbon) quantify completely different but linked processes. Chapter 16 (decomposition) is also disappointing. The authors state that ‘‘the techniques used for the study of seagrass litter are extremely varied. . .’’(p. 321), but, nevertheless, they superficially cover their subject in only eight pages. What about the release and resorption of nutrients during decay? What about the accumulation of refractory material and the long distance transport of detritus? What about anaerobiosis in the sediment? The book closes with Section III, ‘Seagrass Habitat Conservation’, dealing with habitat quality, seagrass transplantation and protective measurements. This section is literally the appendix of the book, and entails mixed feelings. On the one hand, it comprises only circumstantial evidence, without connections to Section II. An obvious question in this context is, e.g. which methods from Section II are the most suitable ones to provide early warning signals of seagrass ecosystem deterioration? The protective measurements (Chapter 23) have a very limited usefulness, because they are very much dependent on the legal instruments and management practices applied in a specific country. On the other hand, in-depth seagrass habitat conservation deserves an entire handbook, with detailed case studies, ecosystem modelling approaches, interlinks with connected ecosystems, long-term trends connected to climate change, causes of successes and failures in rehabilitation practice, etc. In conclusion: compared to the highly appreciated and compact book of Phillips and McRoy (1990), ‘Seagrass Research Methods’, this book of Short and Coles is voluminous and verbose. As a consequence of the multi-author approach, the content of the book is inconsistent, and the chapters are varying in quality from moderate to excellent. The book is nevertheless the best we have on seagrass research methods, and therefore indispensable for everyone working with seagrasses. I am waiting for a volume on seagrass protection and habitat conservation.
Piet H. Nienhuis Department of Environmental Studies, Faculty of Science, University of Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands E-mail address: [email protected] PII: S 0 0 4 4 - 8 4 8 6 ( 0 2 ) 0 0 3 0 7 - 1
405
one weakness of this book is the limited number of references cited. This makes it difficult for the reader to go back to the original reference to examine the results in more details. This is likely an editorial decision aimed at preserving the appeal of this book for a wider audience. However, the information presented is generally detailed and accurate enough to provide the reader with a good overview or a starting point when documenting a topic. I have kept my copy of French edition close at hand since 2000 since I frequently had to refer to it for research and teaching purposes. Translated in English, this book has become even more useful to me. The French-to-English translation is very good. The translation conveys the more literary writing style used by most French authors. This makes the reading a little less dry than is commonly the case with many English language textbooks. The only negative point is that, in some cases, literal translation of French terminology and abbreviations is used instead of more widely used and accepted English terms and abbreviations. In conclusion, this book is an excellent reference book, a worth buy for all readers interested in fish and crustacean nutrition. This book would be a very useful companion textbook for undergraduate fish nutrition and aquaculture courses. Dominique P. Bureau Fish Nutrition Research Laboratory, Department of Animal and Poultry Science, University of Guelph, Guelph, ON, Canada N1G 2W1 E-mail address: [email protected] Tel.: +1-519-8244120x6688; fax: +1-519-767-0573 PII: S 0 0 4 4 - 8 4 8 6 ( 0 2 ) 0 0 2 6 1 - 2
Global Seagrass Research Methods F.T. Short and R.G. Coles (eds.). Elsevier, Amsterdam. (2001). 482 pp., Price EUR 174.71; USD 189.50, ISBN 0-444-50891-0 A new book on seagrass research methods. To satisfy my curiosity, the first thing I did was checking the book on its usefulness regarding the solution to minor practical problems I experienced myself in the course of the years. How do we quantitatively remove sediment from the seagrass root system? Page 149: ‘‘At the laboratory, clean both aboveand belowground samples of any remaining sediment. . .by rinsing the samples with seawater.’’ Next question: How do we sample seagrass epiphytes in a quantitative way, especially the calcareous ones? Page 149: ‘‘Plant samples are scraped free of epiphytes using a razor blade or glass microscope slide’’ Page 201 –202: ‘‘Epiphytes scraped from all leaves in a quadrate (0.2 0.2 m) may be bulked. . .’’. Page 213: ‘‘Place samples in a dilute solution of 5% nitric or hydrochloric acid until bubbles are no longer produced. Wash the epiphyte sample in distilled water to remove the acid before weighing.’’ That’s it, nothing has changed since 1990, but every experienced seagrass worker knows that these recipes do not provide us with quantitative data. On second thought, this is no doubt a thorough and informative volume on research methods dealing with one of the most productive coastal habitats, which has become
406
Book reviews
increasingly recognised over the last 35 years. The book is carefully produced, it contains excellent colour photographs, and a series of nice new diagrams. The format of the paragraphs is consistent; it starts with an introduction, followed by the objectives, then necessary materials and equipment, then methods, ending with a section on troubleshooting and hints, followed by a discussion. Particularly, the ‘troubleshooting and hints’ part is very instructive. Besides Fred Short and Robert Coles as editors, Catherine A. Short is mentioned as technical editor. To my opinion, she deserves the full honour of being coeditor of this volume. The editors assembled 51 authors from around the world, but the choice of the authors is biased, as the NE Atlantic and Mediterranean researchers are highly underrepresented. The editors asked the authors to display the most globally useful techniques, not necessarily the newest ones or those requiring equipment available only to the economically privileged. That is of itself a commendable ambition, but requiring access to a DNA analysis laboratory (Ingliss) and to the ‘relatively expensive’ (p. 196) PAM fluorometry (Beer) is not directly illustrative of this approach. The book is organised into three sections. The first section covers the current world distribution of seagrasses; it further provides identification keys and descriptions, and details on reproduction and phenology. This is a useful and compact section. It is reminiscent of an abridged update of Den Hartog’s (1970) famous monograph ‘Seagrasses of the World’, but the (scanty) drawings are too small and unclear (e.g. 1.7 and 3.1), and detailed distribution maps are lacking. Section II covers the main content of the book: a global set of methods for seagrass environments, starting with general sampling and collection procedures and statistical issues, followed by an analysis and presentation of information on spatial data distribution, such as mapping and remote sensing. These are originally arranged and very interesting chapters. The next group of chapters focuses on the plants themselves: seeds and genetics, abundance and distribution, growth and photosynthesis. Methods for the measurement of these aspects of seagrasses represent the basic range of parameters fundamental to most seagrass studies. The book continues with methods for measuring algae and animals associated to the seagrass ecosystem, followed by methods to study grazing and decomposition. The section ends with a display of methods to quantify physical and chemical variables that regulate plant and animal activities and are determinants of seagrass distribution. No doubt, all chapters contain important information, but notwithstanding the rather consequent consistency in the format, the content of the papers is inconsistent (see, e.g. my appreciation of chapter 8 versus chapters 9 and 16). But this is probably due to the fact that so many different authors have contributed to the book. Particularly, a multi-author book on methodology needs more consistency in the presentation as regards content of the different techniques, and less overlap in statistical treatments. My suggestion is to combine all statistical methods in one chapter, with cross-references to the other chapters, because now there is quite some redundancy in the explanation and the use of PCA, CCA, ANOVA and other statistical treatments. Chapter 8 (growth and production ) gives an excellent description of direct seagrass growth measurements methods, especially the leaf and rhizome marking method. Step by step, the methodology and the protocols are explained. My only comment concerns the fact that the plastochrone method should have been described in a more critical context. The hint in the sampling protocol is illustrative of the lack of that approach: ‘Select a
Book reviews
407
station for growth measurements; areas with broken or grazed leaf tips should be avoided’ (p.167). Broken and fully epiphytized leaves demonstrate often signs of habitat deterioration. Particularly, in these spots it is very important to know whether the seagrass is able to survive (positive net primary production signal) or will die off (negative production signal)—see also Section III. Chapter 9 (photosynthesis) is disappointing; it is rather an incomplete review than a detailed description of research methods. What about the use of microelectrodes measuring oxygen microprofiles in the sediment, as early warning signals of habitat deterioration (see my comment referring to Section III)? Not a word on community metabolism measurements, in the proper set up showing oxygen signals of all plant and animal components in the enclosure. Not a positive word on the use of radioisotopes (‘not recommended’ p. 184), although the two methods (oxygen and radioactive carbon) quantify completely different but linked processes. Chapter 16 (decomposition) is also disappointing. The authors state that ‘‘the techniques used for the study of seagrass litter are extremely varied. . .’’(p. 321), but, nevertheless, they superficially cover their subject in only eight pages. What about the release and resorption of nutrients during decay? What about the accumulation of refractory material and the long distance transport of detritus? What about anaerobiosis in the sediment? The book closes with Section III, ‘Seagrass Habitat Conservation’, dealing with habitat quality, seagrass transplantation and protective measurements. This section is literally the appendix of the book, and entails mixed feelings. On the one hand, it comprises only circumstantial evidence, without connections to Section II. An obvious question in this context is, e.g. which methods from Section II are the most suitable ones to provide early warning signals of seagrass ecosystem deterioration? The protective measurements (Chapter 23) have a very limited usefulness, because they are very much dependent on the legal instruments and management practices applied in a specific country. On the other hand, in-depth seagrass habitat conservation deserves an entire handbook, with detailed case studies, ecosystem modelling approaches, interlinks with connected ecosystems, long-term trends connected to climate change, causes of successes and failures in rehabilitation practice, etc. In conclusion: compared to the highly appreciated and compact book of Phillips and McRoy (1990), ‘Seagrass Research Methods’, this book of Short and Coles is voluminous and verbose. As a consequence of the multi-author approach, the content of the book is inconsistent, and the chapters are varying in quality from moderate to excellent. The book is nevertheless the best we have on seagrass research methods, and therefore indispensable for everyone working with seagrasses. I am waiting for a volume on seagrass protection and habitat conservation.
Piet H. Nienhuis Department of Environmental Studies, Faculty of Science, University of Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands E-mail address: [email protected] PII: S 0 0 4 4 - 8 4 8 6 ( 0 2 ) 0 0 3 0 7 - 1