BOOK REVIEWS life history and ecology of their representative organisms. Likewise, patterns of marine and terrestrial diversity in Arctic and Antarctic habitats can be explained only by understanding their geological and/or glaciological history – the depauperate terrestrial biota of the Antarctic relative to the Arctic is a dual function of the isolation and youth of Antarctic habitats. In contrast, Antarctic marine biota have evolved in situ over tens of millions of years, leading to higher endemicity and greater diversity than the Arctic. The biological consequences of increased UV-B radiation levels as a result of the ozone hole above the Antarctic, recently discovered in the 1980s, still remain debatable. Media and public understanding often confuses the ozone hole with the completely separate process of global warming, although there might be a link via Antarctic marine biology. UVrelated damage to a marine primary producer (the alga Phaeocystis) may reduce the amount of dimethyl sulphide released into the atmosphere. Currently, the Southern Ocean accounts for c. 10% of global release of this chemical, a precursor of a potent cloud nucleator. Subsequent changes in cloud formation will affect absorption and release of energy by the atmosphere, and hence the climate. Until recently, the contribution of humans, particularly in the past two centuries, has been little short of a litany of uncontrolled damage, from exploitation of marine mammal and fish stocks, through introduction of alien species, to pollution, culminating in the vast oil spills from the Exxon Valdez in Alaska and pipelines in Arctic Russia. Fogg demonstrates the unique role of the polar regions as barometers of human impact on the Earth system. On a lighter note, Fogg describes the remarkable tenacity of polar organisms, from the ability of propagules and microorganisms to survive several thousand years in ice columns, through tolerance of temperature, radiation, desiccation and osmotic extremes, to incredibly low growth rates. (Did you know that Antarctic endolithic algae can achieve only one cell division each year, or that Polar bear fur is such an effective insulator that the animals are invisible to infra-red imagers?) This is a masterful synthesis of information across many disciplines about the two polar regions giving, as intended, a readily accessible overview that deserves a long future role as the foundation to the teaching and understanding of polar biology.
Peter Convey British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge, UK CB3 0ET ([email protected]
) TREE vol. 14, no. 4 April 1999
Natural capital? Conservation of Biological Resources by E.J. Milner-Gulland and R. Mace Blackwell Science, 1998. £24.95 pbk (xvi 1 404 pages) ISBN 0 86542 738 0
hat is conservation? Milner-Gulland and Mace state that ‘biological conservation means maintaining biodiversity, which involves the prevention of species extinction, but it is much broader than this.’ However, ‘when species are considered as resources, then conservation frequently has a slightly different meaning, the emphasis is usually on sustaining the resource so that profitable exploitation can continue.’ The argument about whether conservation means preservation or optimal exploitation will doubtless never be resolved. The authors strike a nice balance between the two meanings, although the question of the economic benefits of protecting biodiversity per se is not discussed. Conservation of Biological Resources, directed to students, resource managers and concerned lay persons, is in two parts: theory and case studies. Ten chapters, by expert contributors, present contemporary case studies ranging from wildlife management in Kenya to management of the Loligo squid fishery in the Falkland Islands. These chapters are useful, not only for the descriptions of the basic biology involved, but especially for their discussion and analysis of social, economic and political forces that often inhibit conservation. One theme that emerges, if only implicitly, is that the world is becoming a very crowded place. Expanding human populations are gradually eliminating the last of the earth’s wildernesses (except perhaps polar regions), while also exerting ever greater demands on natural resources. Even socalled protected areas are under increasing pressure from local human populations (which are often poor and sometimes destitute) and expanding tourist industries. The basic assumption underlying this and similar books seems to be that conservation can be achieved only if we can learn to manage resource systems properly. A more cynical, if more realistic, view would be that attempts at biological conservation are unlikely to succeed in the long term unless we can limit human population growth. Unfortunately, resource-management problems, such as saving the few remaining rhinoceroses or preventing overfishing, although difficult, might be vastly simpler than the problems of reducing poverty and
controlling population growth. Other conservation related topics not discussed in this book include global climate change, environmental pollution, endocrine disruptors, desertification and soil erosion. Perhaps no single book could do justice to all of the resource-conservation issues now facing mankind, in terms of discussing practical solutions, but despite its limited scope, this book is well worth studying. The theoretical chapters suffer from several inaccurate and misleading statements. For example, the discussion of advantages and disadvantages of constanteffort versus constant-proportion harvesting of a population is very confused. The authors assert that constant-effort harvesting ‘can be administered without monitoring population size…’, a dangerously misleading statement in view of the notorious difficulties in measuring and controlling effort. Similarly, they claim that under constant-proportion harvesting ‘harvesters do not make constant attempts to circumvent the regulations if they are free to use any technology they please.’ No justification is offered for this amazing assertion, which is just false. These statements seem to arise from the authors’ failure to clearly define the concept of effort (which is difficult to define pragmatically), or to consider how the two management strategies would be implemented. For example, a constant-proportion strategy would have to be implemented by setting annual harvest quotas, which always leads to monitoring and enforcement difficulties in common property resources. These might seem like minor academic errors, but halfbaked models and theories (which often assume the role of dogmatic beliefs) have long contributed to the dismal history of fisheries and other resource management problems. The concept of resources as forms of ‘natural capital’, now commonplace in ecological economics1, is not made use of in this book. Conceptualizing natural resources as natural capital has two advantages: it locates resource conservation as a branch of standard economics, and at the same time recognizes that biological resources have unique characteristics that distinguish them from traditional types of human-made capital.
C.W. Clark 9531 Finn Road, Richmond, BC, Canada V7A 2L3 ([email protected]
References 1 Jansson, A. et al., eds (1994) Investing in Natural Capital: the Ecological Economics Approach to Sustainability, Island Press
0169-5347/99/$ – see front matter © 1999 Elsevier Science. All rights reserved.