Brings together the results of research programmes in Austria, Canada, U.S.A., Finland, Norway, Sweden, Greenland, U.K., Ireland, U.S.S.R. and the Antarctic describing tundra and related ecosystems in a comparative manner. Includes sections on the abiotic, plant production and fauna components, the decomposer cycle and the utilisation and conservation of tundra.

One issue each year devoted to the annual report.

Systems Analysis and Simulation in Ecology, Volume III, and its companion, Volume IV, grew out of a symposium, Modeling and Analysis of Ecosystems, held at the University of Georgia, 1-3 March 1973. The purposes of the meeting were to (i) review the status of ecosystem modeling, simulation, and analysis; (ii) provide a forum for interaction between U.S. International Biological Program (IBP) Biome modeling programs and selected non-IBP investigations involving systems approaches to ecosystem analysis; and (iii) identify and promote dialogue on key issues in macrosystem modeling. The volume is organized into two parts. Part I treats ecosystem modeling in the U.S. IBP. The introductory chapter is followed by five chapters describing grassland, deciduous forest, desert, tundra, and coniferous forest biome modeling. The concluding chapter is one of critique and evaluation. Part II is devoted mainly to freshwater ecosystems, grading into the estuarine system in the last chapter. The five chapters of this section encompass a simple thermal ecosystem, small woodland streams, a reservoir, one of the Great Lakes, a lake reclaimed from eutrophication, and a major estuary under stress of human impact.

O. L. LANGE, P. S. NOBEL, C. B. OSMOND, and H. ZIEGLER In the last volume of the series 'Physiological Plant Ecology' we have asked contributors to address the bases of ecosystem processes in terms of key plant physiological properties. It has often been suggested that it is not profitable to attempt analysis of complex living systems in terms of the properties of component individuals or populations, i. e. , the whole is more than the sum of its parts. Nevertheless, assessments of ecological research over the last century show that other approaches are seldom more helpful. Although it is possible to describe complex systems of living organisms in holistic terms, the most useful descriptions are found in terms of the birth, growth and death of individ uals. This allows analysis of performance of the parts of the whole considering their synergistic and antagonistic interrelationships and is the basis for a synthe sis which elucidates the specific properties of a system. Thus it seems that the description of ecosystem processes is inevitably anchored in physiological under standing. If enquiry into complex living systems is to remain a scientific exercise, it must retain tangible links with physiology. Of course, as was emphasized in Vol. 12A, not all of our physiological understanding is required to explore ecosystem processes. For pragmatic purposes, the whole may be adequantely represented as a good deal less than the sum of its parts.

Global warming is likely to have the greatest impact at high latitudes, making the Arctic an important region both for detecting global climate change and for studying its effects on terrestrial ecosystems. The chapters in this volume address current and anticipated impacts of global climate change on Arctic organisms, populations, ecosystem structure and function, biological diversity, and the atmosphere.