Ecologists, although they acknowledge the problems involved, generally conduct their research on too few species, in too small an area, over too short a period of time. In The Balance of Nature?, a work sure to stir controversy, the distinguished theoretical ecologist Stuart L. Pimm argues that ecology therefore fails in many ways to address the enormous ecological problems now facing our planet.

Ecologists describing phenomena on larger scales often use terms like "stability," "balance of nature," and "fragility," and Pimm begins by considering the various specific meanings of these terms. He addresses five kinds of ecological stability—stability in the strict sense, resilience, variability, persistence, and resistance—and shows how they provide ways of comparing natural populations and communities as well as theories about them. Each type of stability depends on characteristics of the species studied and also on the structure of the food web in which the species is embedded and the physical features of the environment.

The Balance of Nature? provides theoretical ecology with a rich array of questions—questions that also underpin pressing problems in practical conservation biology. Pimm calls for nothing less than new approaches to ecology and a new alliance between theoretical and empirical studies.

Food webs are diagrams depicting which species interact or in other words, who eats whom. An understanding of the structure and function of food webs is crucial for any study of how an ecosystem works, including attempts to predict which communities might be more vulnerable to disturbance and therefore in more immediate need of conservation.

Although it was first published twenty years ago, Stuart Pimm's Food Webs remains the clearest introduction to the study of food webs. Reviewing various hypotheses in the light of theoretical and empirical evidence, Pimm shows that even the most complex food webs follow certain patterns and that those patterns are shaped by a limited number of biological processes, such as population dynamics and energy flow. Pimm provides a variety of mathematical tools for unravelling these patterns and processes, and demonstrates their application through concrete examples. For this edition, he has written a new foreword covering recent developments in the study of food webs and demonstrates their continuing importance to conservation biology.

What species occur where, and why, and why some places harbor more species than others are basic questions for ecologists. Some species simply live in different places: fish live underwater; birds do not. Adaptations follow: most fish have gills; birds have lungs. But as Patterns in Nature reveals, not all patterns are so trivial.

Travel from island to island and the species change. Travel along any gradient—up a mountain, from forest into desert, from low tide to high tide on a shoreline —and again the species change, sometimes abruptly. What explains the patterns of these distributions? Some patterns might be as random as a coin toss. But as with a coin toss, can ecologists differentiate associations caused by a multiplicity of complex, idiosyncratic factors from those structured by some unidentified but simple mechanisms? Can simple mechanisms that structure communities be inferred from observations of which species associations naturally occur? For decades, community ecologists have debated about whether the patterns are random or show the geographically pervasive effect of competition between species. Bringing this vigorous debate up to date, this book undertakes the identification and interpretation of nature’s large-scale patterns of species co-occurrence to offer insight into how nature truly works.

Patterns in Nature explains the computing and conceptual advances that allow us to explore these issues. It forces us to reexamine assumptions about species distribution patterns and will be of vital importance to ecologists and conservationists alike.