Resource added for the Landscape Horticulture Technician program 100014.

The natural communities of the world are diverse, and many schools of ecology have developed classifications of communities in partial independence of one another. There is consequently a vast and widely dispersed literature on the classification of plant and animal communities, comprising divergent approaches of different schools and representing a great experiment on the usefulness of different possibilities for classification. The editor sought in a re view monograph of 1962 to summarize these schools and their history, and in 1973 published a treatise on 'Ordination and Clas sification of Communities' as volume 5 of the Handbook of Vegetation Science. We were fortunate, in preparing the latter work, to have a truly international panel of authors to discuss different major ap proaches to classification. This second edition of the book of 1973 is intended to make the work more widely available in a less expensive form as companion volumes on ordination and on classification of plant communities.

Although ecologists have long considered morphology and life history to be important determinants of the distribution, abundance, and dynamics of plants in nature, this book contains the first theory to predict explicitly both the evolution of plant traits and the effects of these traits on plant community structure and dynamics. David Tilman focuses on the universal requirement of terrestrial plants for both below-ground and above-ground resources. The physical separation of these resources means that plants face an unavoidable tradeoff. To obtain a higher proportion of one resource, a plant must allocate more of its growth to the structures involved in its acquisition, and thus necessarily obtain a lower proportion of another resource. Professor Tilman presents a simple theory that includes this constraint and tradeoff, and uses the theory to explore the evolution of plant life histories and morphologies along productivity and disturbance gradients. The book shows that relative growth rate, which is predicted to be strongly influenced by a plant's proportional allocation to leaves, is a major determinant of the transient dynamics of competition. These dynamics may explain the differences between successions on poor versus rich soils and suggest that most field experiments performed to date have been of too short a duration to allow unambiguous interpretation of their results.