Diversity within and among living organisms is both a biological impera tive and a biological conundrum. Phenotypic and genotypic diversity is the critical currency ofecological interactions and the evolution of life. Thus, it is not unexpected to find vast phytochemical diversity among plants. However, among the most compelling questions which arise among those interested in ecological phytochemistry is the extent, nature, and reasons for the diversity of chemieals in plants. The idea that natural products (secondary metabolites) are accidents of metabolism and have no biological function is an old one which has resurfaced recently under a new term "redundancy. " Redundancy in the broader sense can be viewed as duplication of effort. The co-occurrence of several classes of phytochemieals in a given plant may be redundancy. Is there unnecessary duplication of chemical defense systems and ifso, why? What selective forces have produced this result? On the other hand, why does the same compound often have multiple functions? At a symposium of the Phytochemical Society of North America held in August 1995, in Sault Ste. Marie, Ontario, Canada, the topic "Phytochernical Redundancy in Ecological Interactions" was discussed. The chapters in this volume are based on that symposium. They both stimulate thought and provide some working hypotheses for future research. It is being increasingly recognized that functional diversity and multiplicity of function of natural products is the norm rather than the exception."

Diversity within and among living organisms is both a biological impera tive and a biological conundrum. Phenotypic and genotypic diversity is the critical currency ofecological interactions and the evolution of life. Thus, it is not unexpected to find vast phytochemical diversity among plants. However, among the most compelling questions which arise among those interested in ecological phytochemistry is the extent, nature, and reasons for the diversity of chemieals in plants. The idea that natural products (secondary metabolites) are accidents of metabolism and have no biological function is an old one which has resurfaced recently under a new term "redundancy. " Redundancy in the broader sense can be viewed as duplication of effort. The co-occurrence of several classes of phytochemieals in a given plant may be redundancy. Is there unnecessary duplication of chemical defense systems and ifso, why? What selective forces have produced this result? On the other hand, why does the same compound often have multiple functions? At a symposium of the Phytochemical Society of North America held in August 1995, in Sault Ste. Marie, Ontario, Canada, the topic "Phytochernical Redundancy in Ecological Interactions" was discussed. The chapters in this volume are based on that symposium. They both stimulate thought and provide some working hypotheses for future research. It is being increasingly recognized that functional diversity and multiplicity of function of natural products is the norm rather than the exception.

Today, 55% of the world's human population lives in urban areas. By 2030, up to 90% of the global human population will live in cities and the global population is expected to increase by 68% by 2050. Although land cover categorized as "urban" is a relatively small fraction of the total surface of the Earth, urban areas are major driving forces in global environmental change, habitat loss, threats to biodiversity, and the loss of terrestrial carbon stored in vegetation biomass. These and many other factors highlight the need to understand the broad-scale impacts of urban expansion as it effects the ecological interactions between humans, wildlife and plant communities. In a series of essays by leading experts this book defines urban ecology, and provides much-needed focus on the main issues of this increasingly important subdiscipline such as the impacts of invasive species, protecting pollinators in urban environments, the green cities movement and ecological corridors. The book stresses the importance of understanding ecological forces and ecosystem services in urban areas and the integration of ecological concepts in urban planning and design. The creation of urban green spaces is critical to the future of urban areas, enhancing human social organization, human health and quality of life. Urban ecology is becoming a foundational component of many degree programs in universities worldwide and this book will be of great interest to students and researchers in ecology and conservation science, and those involved in urban planning and urban environmental management.

This book addresses the fundamental issues of predator-prey interactions, with an emphasis on predation among arthropods, which have been better studied, and for which the database is more extensive than for the large and rare vertebrate predators. The book should appeal to ecologists interested in the broad issue of predation effects on communities.