in theory communities may expect to get the level ofquality they are prepared to pay for, withoutcooperation this cannot be achieved against theinfluence of larger scale factors beyond their control.If the politicians of the future were all to read thisbook during their studies, one could have more hopethat the hard decisions necessary would be taken.

While the book is American, this rarely intrudes.There is almost exclusive use of SI units and theconsiderations are worldwide. Norway is credited withthe greatest rate of freshwater runoff per km2 of landarea, and Singapore with most progress of southeastAsian countries in environmental managementÐapplying a `polluter pays' principle through effectiveadministrative and enforcement measures.

Perhaps what makes the book such an easy andcompelling read is the total absence of formulae orequations, often replaced by diagrams, in some of whichthe different shades of grey are hard to resolve. Thisapparent aversion to formulae extends to a failure tomention the important part that modelling has to play inmany aspects of water quality management, but this isenough for another book in its own right.

TOM LEATHERLAND

Scottish Environment Protection Agency,Edinburgh, UK

AQUATIC PLANTS IN BRITAIN AND IRELAND,C. D. Preston and J. M. Croft, Harley Books,Colchester, UK, 1997, 368 pp. Price £25.00. ISBN 0946589 550 (hb only).

This book summarizes the distribution, habitats andreproductive biology of 200 aquatic vascular plants inBritain and Ireland. This may not excite everyone, butLord De Ramsey, in his Foreword, extols its value `bothas an atlas of distribution and a compendium ofscientific information'.

For anyone who is interested in aquatic plants, thebook is a must. The maps are extremely valuable inproviding a break-down of records for each species: pre-1950, 1950±1969 and post-1970 being depictedseparately. At a glance it is possible to see theexplosive expansion of aliens such as Crassula helmsiiand Elodea nuttallii and the contrasting crash of nativessuch as Potamogeton acutifolius and P. praelongus fromsome regions.

There is a huge amount of information packed intothe text. Accounts for all British species in the bookbegin with identifying which family and genus theybelong to and how these are distributed in Europe andthe rest of the world. Some hybrids and sub-species arecovered too. The accounts are all supported by usefultips on identification, with some even providing detailsof physiology and cytology in support of their taxonomyand habitat preferences. Extensive reference to theliterature, and the authors' own great depth ofknowledge, gives the reader great confidence. Thereare `light asides' too; one such refers to the use of Azollaby the Chinese as green manure more than 2000 yearsagoÐit's nice to know it does have its uses!

I have had my book for a month and have used itconstantly. In addition to being a wonderful referencebook for individual species, it has valuable informationon rare and threatened species. It will be a constantcompanion of mine whether in the office, travelling ordoing field work. It is a book which reflects very well onthe three organizations responsible for its productionÐthe Institute of Terrestrial Ecology, Joint NatureConservation Committee and the EnvironmentAgency. It is noteworthy too that Harley Books haveproduced such an attractive volume at an affordableprice. Perhaps in future additions the illustrations can beimproved to reflect the very highest standard of the text.

NIGEL HOLMES

Alconbury Environmental ConsultantsWarboys, UK

330 BOOK REVIEW

#1997 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst., Vol. 7, 327±330 (1997)