What is the minimum dimension of a niche space necessary to represent the overlaps among observed niches? This book presents a new technique for obtaining a partial answer to this elementary question about niche space. The author bases his technique on a relation between the combinatorial structure of food webs and the mathematical theory of interval graphs. Professor Cohen collects more than thirty food webs from the ecological literature and analyzes their statistical and combinatorial properties in detail. As a result, he is able to generalize: within habitats of a certain limited physical and temporal heterogeneity, the overlaps among niches, along their trophic (feeding) dimensions, can be represented in a one-dimensional niche space far more often than would be expected by chance alone and perhaps always. This compatibility has not previously been noticed. It indicates that real food webs fall in a small subset of the mathematically possible food webs. Professor Cohen discusses other apparently new features of real food webs, including the constant ratio of the number of kinds of prey to the number of kinds of predators in food webs that describe a community. In conclusion he discusses possible extensions and limitations of his results and suggests directions for future research.
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.
Frogs, minnows, snails, ducks, catfish, and muskrats are a few of the animals that make up a lake and pond food web. But do you know why mosquitoes, mold, water lilies, and bacteria are important too? Or how humans can change the health of a lake or a pond? See lake and pond food webs in action in this fascinating book.
Department of Ecology and Evolutionary Biology Mercedes Pascual
Author: Department of Ecology and Evolutionary Biology Mercedes Pascual
Publisher: Oxford University Press
Food webs are one of the most useful, and challenging, objects of study in ecology. These networks of predator-prey interactions, conjured in Darwin's image of a "tangled bank," provide a paradigmatic example of complex adaptive systems. This book is based on a February 2004 Santa Fe Institute workshop. Its authors treat the ecology of predator-prey interactions, food web theory, structure and dynamics. The book explores the boundaries of what is known of the relationship between structure and dynamics in ecological networks and will define directions for future developments in this field.
Multispecies Assemblages, Ecosystem Development and Environmental Change
Author: Peter C de Ruiter
Dynamic Food Webs challenges us to rethink what factors may determine ecological and evolutionary pathways of food web development. It touches upon the intriguing idea that trophic interactions drive patterns and dynamics at different levels of biological organization: dynamics in species composition, dynamics in population life-history parameters and abundances, and dynamics in individual growth, size and behavior. These dynamics are shown to be strongly interrelated governing food web structure and stability and the role of populations and communities play in ecosystem functioning. Dynamic Food Webs not only offers over 100 illustrations, but also contains 8 riveting sections devoted to an understanding of how to manage the effects of environmental change, the protection of biological diversity and the sustainable use of natural resources. Dynamic Food Webs is a volume in the Theoretical Ecology series. Relates dynamics on different levels of biological organization: individuals, populations, and communities Deals with empirical and theoretical approaches Discusses the role of community food webs in ecosystem functioning Proposes methods to assess the effects of environmental change on the structure of biological communities and ecosystem functioning Offers an analyses of the relationship between complexity and stability in food webs
Food webs have now been addressed in empirical and theoretical research for more than 50 years. Yet, even elementary foundational issues are still hotly debated. One difficulty is that a multitude of processes need to be taken into account to understand the patterns found empirically in the structure of food webs and communities. Food Webs and Biodiversity develops a fresh, comprehensive perspective on food webs. Mechanistic explanations for several known macroecological patterns are derived from a few fundamental concepts, which are quantitatively linked to field-observables. An argument is developed that food webs will often be the key to understanding patterns of biodiversity at community level. Key Features: Predicts generic characteristics of ecological communities in invasion-extirpation equilibrium. Generalizes the theory of competition to food webs with arbitrary topologies. Presents a new, testable quantitative theory for the mechanisms determining species richness in food webs, and other new results. Written by an internationally respected expert in the field. With global warming and other pressures on ecosystems rising, understanding and protecting biodiversity is a cause of international concern. This highly topical book will be of interest to a wide ranging audience, including not only graduate students and practitioners in community and conservation ecology but also the complex-systems research community as well as mathematicians and physicists interested in the theory of networks. "This is a comprehensive work outlining a large array of very novel and potentially game-changing ideas in food web ecology." —Ken Haste Andersen, Technical University of Denmark "I believe that this will be a landmark book in community ecology … it presents a well-established and consistent mathematical theory of food-webs. It is testable in many ways and the author finds remarkable agreements between predictions and reality." —Géza Meszéna, Eötvös University, Budapest
Snakes, lizards, rabbits, mice, mountain lions, and hawks are some of the many animals that make up a desert food web. But do you know how desert animals depend on cactuses, grasses, and other plants to stay alive? Or why tiny insects, fungi, and bacteria may be among the most important living things in a desert? See desert food webs in action in this fascinating book.
Scientists rely on food webs—complex networks that trace the flow of nutrients and energy between species and through ecosystems—to understand the infrastructure of ecological communities. But given the complexities of food webs—think of following the flow of nutrients through the microbes, fungi, roots, worms, ants, and birds that pass over or through a single cubic meter of prairie soil—it's not difficult to see why most experiments on food-web dynamics focus on small, local habitats. Yet as this book convincingly shows, important insights come when scientists expand the temporal and spatial scope of their research to look at the ways energy, organisms, nutrients, and pollutants flow not just at the local level, but across whole landscapes—between and among food webs in a wide variety of habitats. Paying special attention to the fertile boundaries between terrestrial, freshwater, and marine ecosystems, Food Webs at the Landscape Level not only shows what this new methodology means for ecology, conservation, and agriculture but also serves as a fitting tribute to Gary Polis and his major contributions to the field.