Ecology. Michael Begon

since the most primitive humans had to understand, as a matter of necessity, the dynamics of the environment in which they lived. We pursued that cave painting theme for two further editions, but for the fourth edition, replaced it with its modern equivalent, urban graffiti. This captured the idea that we, as a species, are still driven to broadcast our feelings graphically and publicly, but the cave painting’s celebration of nature’s bounty had been replaced by an impassioned plea for its protection. Now, 14 years on, the image on our cover, and its message, are darker and more desperate. Instead of focusing on those who are pleading, on nature’s behalf, for respect, this time we shine our light on man the destroyer – obliterating the heritage in our cave painting as he is threatening our natural heritage (the inspiration coming from graffiti artist Banksy, who used a similar idea in an art work involving a water blaster). The ecosystem on our front cover is still there – but it is disappearing.

This evolving image reminds us, too, that 34 years ago it seemed acceptable for ecologists to hold a comfortable, detached position, from which the ecological communities around us were simply material for which we sought a scientific understanding. Now, we must accept the immediacy of the environmental problems that threaten us and the responsibility of ecologists to come in from the sidelines and play their full part in addressing these problems. Applying the principles that emerge from the study of ecology is not only a practical necessity, but also as challenging as deriving those principles in the first place. Thus, in this edition, two whole chapters and one half of another are devoted entirely to applied topics, and examples of how ecological principles have been applied to problems facing us appear, and are highlighted, throughout the remaining 19 chapters. Nonetheless, we remain wedded to the belief that environmental action can only ever be as sound as the ecological principles on which it is based. Hence, while we have tried harder than ever to help improve preparedness for addressing the environmental problems of the years ahead, the book remains, in its essence, an exposition of the science of ecology.

About this fifth edition

      Hence, we have aimed to make this fifth edition an up‐to‐date guide to ecology now. To this end, the results from around 1000 studies have been newly incorporated into the text, most of them published since the fourth edition. Nonetheless, we have resisted the temptation to lengthen the text, mindful that, clichéd as it may be, less is often more. We have also consciously attempted, while including so much modern work, to avoid bandwagons that seem likely to have run into the buffers by the time many will be using the book. Of course, we may also, sadly, have excluded bandwagons that go on to fulfil their promise.

      Having said this, we hope, still, that this edition will be of value to all those whose degree programme includes ecology and all who are, in some way, practicing ecologists. Certain aspects of the subject, particularly the mathematical ones, will prove difficult for some, but our coverage is designed to ensure that wherever our readers’ strengths lie – in the field or laboratory, in theory or in practice – a balanced and up‐to‐date view should emerge.

      Different chapters of this book contain different proportions of descriptive natural history, physiology, behaviour, rigorous laboratory and field experimentation, careful field monitoring and censusing, and mathematical modelling (a form of simplicity that it is essential to seek but equally essential to distrust). These varying proportions to some extent reflect the progress made in different areas. They also reflect intrinsic differences in various aspects of ecology. Whatever progress is made, ecology will remain a meeting‐ground for the naturalist, the experimentalist, the field biologist and the mathematical modeller. We believe that all ecologists should to some extent try to combine all these facets.

Technical and pedagogical features

      An important technical feature is the incorporation of marginal notes as signposts throughout the text. These, we hope, will serve a number of purposes. In the first place, they constitute a series of subheadings highlighting the detailed structure of the text. However, because they are numerous and often informative in their own right, they can also be read in sequence along with the conventional subheadings, as an outline of each chapter. They should act too as a revision aid for students – indeed, they are similar to the annotations that students themselves often add to their textbooks. Finally, because the marginal notes generally summarise the take‐home message of the paragraph or paragraphs that they accompany, they can act as a continuous assessment of comprehension: if you can see that the signpost is the take‐home message of what you have just read, then you have understood.

      To highlight the link between the pure science of ecology and the application of this knowledge to the many environmental problems that now face us we have introduced a new feature – a systematic presentation of ecological applications, highlighted in special boxes throughout the text.

Acknowledgments

      This is the second major revision we have written as a twosome rather than a trio, and this time the authorship reflects this. Nonetheless, while little remains of the original text, we are deeply conscious of the debt we owe to John Harper, who sadly died in 2009. We cannot promise to have absorbed or, to be frank, to have accepted, every one of his views, but we hope, in this fifth edition, that we have not strayed too far from the paths along which he guided us. If readers recognise any attempts to stimulate and inspire rather than simply to inform, to question rather than to accept, to respect our readers rather than to patronise them, and to avoid unquestioning obedience to current reputation while acknowledging our debt to the masters of the past, then they will have identified John’s intellectual legacy still firmly imprinted on the text.

In previous editions we thanked the great many friends and colleagues who helped us by commenting on various drafts of the text. The effects of their contributions are still strongly evident in the present edition. This fifth edition was also read by a series of reviewers, and we are delighted to be able to acknowledge their help. Thanks to David Atkinson, Richard Bardgett, Rob Brooker, Dylan Childs, Tim Coulson, Hans de Kroon, Andy Fenton, Rob Freckleton, Cristina Garcia, Sue Hartley, Andy Hector, Alan Hildrew, Marcel Holyoak, Dave Hooper, Tony Ives, Xavier Lambin, Steve Long, Michel Loreau, Peter Morin, Asko Noormets, Ilik Saccheri, Ross Thomson, Jake Weiner and Rob Whittaker.

      At our publisher Wiley, we are grateful to Ward Cooper (now moved on), who brought us back within the fold, and throughout the writing and production to Sarah Keegan, Jane Andrew, Jane Grisdale and Debbie Maizels.

      Mike Begon

      Colin Townsend

Introduction: Ecology and its Domain

      Definition and scope of ecology

      The word ‘ecology’ was first used by Ernest Haeckel in 1866. Paraphrasing Haeckel we can describe ecology as the scientific study of the interactions between organisms and their environment. The word is derived from the Greek oikos, meaning ‘home’. Ecology might therefore be thought of as the study of the ‘home life’ of living organisms. A less vague definition was suggested by Krebs (1972): ‘Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms’. Notice that Krebs’ definition does not use the word ‘environment’; to see why, it is necessary to define the word. The environment of an organism consists of all those factors and phenomena outside the organism that influence it, whether these are physical and chemical (abiotic) or other organisms (biotic). The ‘interactions’ in Krebs’ definition are, of course, interactions with these very factors. The environment therefore retains the central position that Haeckel gave it.

      Krebs’ definition has the merit of pinpointing the ultimate subject matter of ecology: the distribution and abundance of organisms – where organisms occur, how many occur there and why. This being so, it might be better still to define ecology as:

      the scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance.

      As