BOOK REVIEWS
hydrological disturbance and stream communities, and further emphasis on the requirement for predictive models of long-term effects of climate on vegetation. Tilman reviews the effects of CO, accumulation on plant communities, and debates whether CO, should be seen as a depletable resource, or as a physical factor. The fifth section, 'Landscape Change and Habitat Fragmentation', includes work on species invasions and extinctions, and a chapter by Hassell, Godfray and Comins on impact on host-parasitoid interactions. Their model reveals that changes in climate could totally undermine the stability of host-parasitoid dynamics. The final section, 'The Context for Population and Community Research on Global Change', outlines policy implications and proposes a research agenda.
Minor criticisms include a failure to include references for some cited papers, and the choice of authors is heavily biased towards the US. However, the breadth of content and detail more than outweigh these criticisms.
Many of the authors call for increased collaboration EL NINO. HISTORICAL AND PALAEOCLIMATIC ASPECTS OF THE SOUTHERN OSCILLATION, H. F. Diaz and V . Markgraf (eds), Cambridge University Press (Cambridge) 1992. No. of