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Résumé :
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This book starts by using the equilibrium, resource-dependent growth isocline approach to competition developed in Tilman (1980,1982) to demonstrate that the long-term average availability of a limiting soil nutrient and of light at the soil surface should depend on the nutrient supply rate and the loss rate of a habitat (Chapter 2). Because plants require both an above-ground resource (light) and below-ground resources (nutrients and water), plants face a tradeoff. To acquire more of one resource necessarily means that they must acquire proportionately less of another. Thus, the pattern of plant allocation to above-versus below-ground structures should influence the competitive ability of a plant in a given habitat (Chapters 4 and 5). However, all allocation to such non-photosynthetic structures as stems and roots necessarily decreases the maximal rate of vegetative growth of a plant (Chapter 3) and can thus greatly influence plant population dynamics (Chapter 6). The transient population dynamics that occur because of differences in maximal growth rates may be a major cause of the pattern of secondary succession, and may make it difficult to interpret the results of many short-term field experiments (Chapter 7). A five-year experimental study of plant distributions and successional dynamics at Cedar Creek Natural History Area, Minnesota, provides a wealth of information, much of it previously unpublished, with which to evaluate the predictions of the theory developed in this book (Chapter 8). The book ends with an exploration of some additional implications of the theory and with suggestions for further research (Chapter 9).
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