THE ECOLOGY OF PLANTS, 2ND EDN.

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It is quite unusual these days in ecological publishing to find a general textbook that deals specifically with the botanical aspects of ecology. Almost all texts in this subject combine animals, plants and microbes within the same covers, partly because all kingdoms are intricately mixed in the configuration of the ecosystem, partly because almost all university ecology classes are taught in an interdisciplinary manner, and perhaps also because the teaching of the subject is thought to benefit from a concentration on interactions between both species and kingdoms. Whatever the reasons, the publication of a textbook of plant ecology is a relatively rare event, but the question must be raised as to whether it is academically profitable. There are many aspects of ecology that are specifically down to plants, and the trapping of solar energy is quite clearly a botanical process upon which almost all other life forms depend. It is entirely reasonable, therefore, that this book begins with photosynthesis: its biochemistry, including its various pathways and their ecological significance, and its variation with light intensity and quality. No animals are needed here, and their exclusion is no loss to the book. The same could possibly be argued for water relations, root–soil interactions and nutrient acquisition. Microbes are clearly important here and are given some coverage, but the lack of zoological input does detract a little from the overall ecological picture, in my opinion. The related section dealing with ecosystem interactions is almost half a book away, and this arrangement fragments some extremely important ecological topics, such as the allocation of resources in a plant and its impact on architecture, microclimate and animal communities. The relationships between a plant’s acquisition of elements and the needs of the grazer, together with the whole field of grazing deterrence by plants would fit logically in sequence here, but a long gap intercedes before even the topic of nutrient cycling is covered, let alone that of secondary compounds in plants. Population ecology follows and is well covered, with plentiful examples of the use of life tables and matrix algebra. This is one of the strongest parts of the book, and makes good use of topic boxes and numerical examples. But once again, I feel that comparisons with the problems facing zoological ecologists dealing with similar problems would be beneficial, even if emphasis were placed inevitably on the contrasts between the two sets of organisms. Evolution follows this section, quite logically, but this account has a rather dusty feel, with a dated emphasis on Clausen, Keck and Hiesey rather than the many exciting developments in the plant molecular field. Reproduction and life history development in plants provides a rich ground for investigating the intricacies of co-evolution, both in pollination and seed dispersal. The subject is very well covered, with many interesting examples and illustrations. The vital role of animals in plant biology cannot be avoided here, and the account would undoubtedly have benefited further if the complexities of animal evolution and adaptation could have been discussed alongside those of the plants that so effectively exploit them. Competition is a fairly safe subject for botanical insularity. Since competitors are essentially vying for the same limited resources, most plants are in competition with other plants. While the limiting resource is light, water or nutrient elements, a plant physiological approach is very acceptable, but what if the competition is for pollinators, as among many alpine plants? This subject could have been given more consideration. Ecosystem processes are given a chapter of their own, but here the lack of animal life becomes particularly unfortunate. Admittedly, biogeochemical cycles are driven largely by geological and botanical processes, aided most admirably by microbes, but patterns of energy flow cannot really be discussed adequately in a book on plant ecology. Pyramids of numbers and biomass have to be neglected, and even the study of succession, which has a very strong botanical driving force, loses some of its glamour if deprived of an energetic, Odumesque ecosystem production vs. respiration approach. My zoological colleagues cringe when I talk of plant communities, but vegetation does give the appearance of assembling itself independently of most animals, and certainly much plant ecological work has concentrated on the nature of such communities. The purist ecologist would argue that the term community cannot be applied selectively to organisms of one trophic level (such as plants); perhaps the term guild would be preferable. The concentration on the plant components of a community can, however, be justified because habitats are often defined and described on the basis of vegetation composition, or even its general structure, as in the case of biome definition. Biomes are indeed given a chapter to themselves in this book, though I confess that the ‘plants only’ approach leaves the account bereft of much of its ecological interest. At least there is one picture of acacia woodland that contains giraffes. The book concludes by looking at ecological questions on a global scale, such as the causes of latitudinal gradients of diversity and the likely consequences of climate change for plant communities of the world. The problems and questions facing ecologists are considerable, but their solution, I fear, is not made easier by ignoring the vast majority of the living species occupying the planet and by concentrating only on the plants. This volume is extremely well produced, rich in attractive illustrations, and supplied with an interesting and informative text. My one very major reservation is my lack of conviction that plant ecology can be studied in isolation from the greater whole.Â