Conservation is a serious business. It is many years since I had a good chuckle at an ecological textbook but Graeme Caughley and Anne Gunn's book contains a gem. A most valuable feature of the book is a series of case studies of animal species which have either declined dramatically or become extinct. Here, we learn about the dodo, the red kite and 16 other unfortunate species including the hispid hare - which apparently is a rabbit. The hare, has "already once disappeared from the view of science" but was rediscovered in 1971 and is now suffering because of habitat decline in northern India. Apparently, a hare was seen in Nepal in 1982 - the first report since one was shot by a certain Lt. Col. Faunthorpe in 1926. As if that was not enough for the species, one was trampled to death by one of the Rajah of Kasmanda's tame elephants in 1956.
Caughley died before the book was completed and in his passing we have lost an excellent scientific communicator. He had a sense of fun and as the tribute in the front of the book explains "he had that gift . . . of making the seemingly complex simple". An understanding of conservation requires an understanding of many facets of basic ecology. Thus purely anecdotal texts never work. Caughley and Gunn have melded together the "theory and practice" and the resultant book is a most stimulating and in parts entertaining read.
By starting with the case studies and a discussion of extinction in prehistory and in historical times, there is a firm basis of examples on which to build the theory of population dynamics and wide-ranging discussion of the attendant problems faced by small populations. This is then examined with reference to the design of nature reserves. It is odd that this section made no reference to the excellent book on reserve design by C. L. Shafer, Nature Reserves, Island Theory and Conservation Practice, but the section on reserves in practice is excellent. We have to accept that many of the reserves around the world are not "designed" but simply "are" and that the theory of reserve design may be academic. The last sections on economics and trade, and international and national legislation provided a fascinating discussion of many of the important issues such as economics and harvesting, and subsistence and commercial harvesting.
Ralph C. MacNally's book is, in stark contrast, rather dry and uninspiring. The book focuses on ecological specialisation and generalisation, ie niche breadth. As MacNally argues, despite the major concerns for the future of global biodiversity, we are failing to stem the extinction of species. Central to this problem is that many of the species dying out are those with specialised or narrow niches - either they have very specific resource needs within their habitat or their habitat is scarce. The more specialised the species the more vulnerable it is and, conversely, the more generalised the species the likelier it is to survive.
This is probably the first book devoted to this field and it contains some valuable work. One such early chapter is the analysis of 145 previous studies into ecological versatility. Included is a table showing the 22 indices that have been used in the literature to measure niche breadth and overlap. It is rather disconcerting that only eight of these are useable (and only two of these designated as recommended) while the other 14 are classed as to be "avoid(ed)". One wonders at the loss of effort this represents.
Versatility is examined from a number of perspectives - interspecific interactions (herbivory, parasitism, predation, omnivory, mutualism), interspecific competition, population structure, and population dynamics. Thus we learn about how versatility is studied and how the theory supports, or otherwise, field observations. What MacNally provides is a thorough understanding of a fundamental aspect of ecology - which is essential when examining biodiversity and species extinctions.
But the book is too biased towards animals, and terrestrial animals at that. It is argued that this was to keep it within "a manageable size" but this is hardly convincing given that the recent thrust of publishing in ecology has been to integrate plant and animal ecology and to draw out the similarities and differences.
Brian S. Rushton is senior lecturer in applied biological and chemical sciences, University of Ulster.
Conservation Biology In Theory and Practice
Author - Graeme Caughley and Anne Gunn
ISBN - 0 86542 431 4
Publisher - Blackwell Science
Price - £32.50
Pages - 459