Species roll call that offers lifeline

Effective conservation action is very dependent on an inventory of bio-diversity, while an accurate inventory of biodiversity necessitates reference to detailed descriptive accounts of faunal components to allow researchers to establish just what they have identified and recorded in the field. This exhaustive text is the long-awaited third volume of a four-volume epic account of the mammal fauna of the neotropics - a vast biogeographical zone encompassing Central and South America. The four countries (Ecuador, Peru, Bolivia, Brazil) covered in this volume are the so-called "core" of South America, which contributes the greater land area to the continent. Despite the size of the area and the immense diversity of mammals (some 650 of the 800 species in South America) encompassed, there is a paucity of information on the constituent species. As John Eisenberg and Kent Redford point out, the mammal fauna is still not well known, and new species continue to be described regularly.

This is above all a reference book, a starting point for taxonomic, conservation and ecological investigations. It was never intended to be used as a field guide (if only by virtue of its large format and weight), for which, in the case of neotropical lowland rainforest mammals, the admirable work of L. H. Emmons is difficult to surpass.

The format remains more or less unchanged from the previous volumes, and although a rather turgid style is adopted for the species accounts, it is probably the most efficient means of conveying this type of knowledge. Although published in mid-1999, I can find no references more recent than 1997. Not that this matters since the quantity of mammalian research being conducted in the neotropics that finds its way into primary research journals seems to be in decline, probably as a result of its poor funding base.

Part one comprises introductory chapters on "Isolation and interchange", "Fossil mammals of the Amazon" and "Pleistocene mammals", which provide a valuable and significant preface to the accounts of the contemporary mammalian fauna that constitute the bulk of the volume. These essays are expertly written by guest authors, world leaders in their respective subject areas. Similarly, the final section of the volume provides authoritative accounts that attempt to synthesise current knowledge on neotropical mammalian biodiversity and community ecology.

Valuable as these accounts are, the real importance of this set of volumes is in presenting up-to-date and comprehensive knowledge at a species level for the entire neotropical mammalian fauna. Part two of the book achieves this admirably, despite a somewhat impoverished knowledge base and occasional reliance on a few somewhat anecdotal accounts.

It is not possible to review the accuracy of the individual accounts for the entire 650 species included, but for these species of which I have a research-based knowledge - cats, bears, tapirs, otters and mustelids - the entries are as detailed and comprehensive as could be expected. Each species account follows a similar format encompassing taxonomic information including: morphometrics and description, details of life history and ecology and conservation status. The text is supported by 19 colour plates and 140 line drawings expertly painted and drawn by Fiona Reed to illustrate small differences between similar species. Particularly valuable are the distribution maps included for each species, which clearly show the estimated range and the specific locations from which museum specimens were collected; although, somewhat surprisingly, some of these maps do not agree with those in Emmons. For "difficult" taxonomic groups, such as rodents, useful keys are provided.

The failing of the book, as for all others of its kind, is the brevity of information on individual species, even those few for which there is a lot of data available. This is necessitated by the large number of species covered. Readers who require more detailed information should consult the primary papers listed at the end of each taxonomic order; these bibliographies provide an invaluable resource for researchers.

One may hope that, as well as providing a reference text, Mammals of the Neotropics will stimulate further investigations of mammalian biodiversity in these areas.

Nigel Dunstone is lecturer in zoology, University of Durham.