An attractive, promising, and frustrating feature of ecology is its complex ity, both conceptual and observational. Increasing acknowledgment of the importance of scale testifies to the shifting focus in large areas of ecology. In the rush to explore problems of scale, another general aspect of ecolog ical systems has been given less attention. This aspect, equally important, is heterogeneity. Its importance lies in the ubiquity of heterogeneity as a feature of ecological systems and in the number of questions it raises questions to which answers are not readily available. What is heterogeneity? Does it differ from complexity? What dimensions need be considered to evaluate heterogeneity ade quately? Can heterogeneity be measured at various scales? Is heterogeneity apart of organization of ecological systems? How does it change in time and space? What are the causes of heterogeneity and causes of its change? This volume attempts to answer these questions. It is devoted to iden tification of the meaning, range of applications, problems, and methodol ogy associated with the study of heterogeneity. The coverage is thus broad and rich, and the contributing authors have been encouraged to range widely in discussions and reflections. vi Preface The chapters are grouped into themes. The first group focuses on the conceptual foundations (Chapters 1-5). These papers exarnine the meaning of the term, historical developments, and relations to scale. The second theme is modeling population and interspecific interactions in hetero geneous environments (Chapters 6 and 7)."

Although complexity surrounds us, its inherent uncertainty, ambiguity, and contradiction can at first make complex systems appear inscrutable. Ecosystems, for instance, are nonlinear, self-organizing, seemingly chaotic structures in which individuals interact both with each other and with the myriad biotic and abiotic components of their surroundings across geographies as well as spatial and temporal scales. In the face of such complexity, ecologists have long sought tools to streamline and aggregate information. Among them, in the 1980s, T. F. H. Allen and Thomas B. Starr implemented a burgeoning concept from business administration: hierarchy theory. Cutting-edge when Hierarchy was first published, their approach to unraveling complexity is now integrated into mainstream ecological thought. This thoroughly revised and expanded second edition of Hierarchy reflects the assimilation of hierarchy theory into ecological research, its successful application to the understanding of complex systems, and the many developments in thought since. Because hierarchies and levels are habitual parts of human thinking, hierarchy theory has proven to be the most intuitive and tractable vehicle for addressing complexity. By allowing researchers to look explicitly at only the entities and interconnections that are relevant to a specific research question, hierarchically informed data analysis has enabled a revolution in ecological understanding. With this new edition of Hierarchy, that revolution continues.

This basic guide introduces the relationships between observation, perception, and learning that form the substance of hierarchy theory. This theory aims to answer the question of whether there is a basic structure to nature, comprising discreet levels of organization within an overall pattern.

This basic guide introduces the relationships between observation, perception, and learning that form the substance of hierarchy theory. This theory aims to answer the question of whether there is a basic structure to nature, comprising discreet levels of organization within an overall pattern.

Although complexity surrounds us, its inherent uncertainty, ambiguity, and contradiction can at first make complex systems appear inscrutable. Ecosystems, for instance, are nonlinear, self-organizing, seemingly chaotic structures in which individuals interact both with each other and with the myriad biotic and abiotic components of their surroundings across geographies as well as spatial and temporal scales. In the face of such complexity, ecologists have long sought tools to streamline and aggregate information. Among them, in the 1980s, T. F. H. Allen and Thomas B. Starr implemented a burgeoning concept from business administration: hierarchy theory. Cutting-edge when Hierarchy was first published, their approach to unraveling complexity is now integrated into mainstream ecological thought. This thoroughly revised and expanded second edition of Hierarchy reflects the assimilation of hierarchy theory into ecological research, its successful application to the understanding of complex systems, and the many developments in thought since. Because hierarchies and levels are habitual parts of human thinking, hierarchy theory has proven to be the most intuitive and tractable vehicle for addressing complexity. By allowing researchers to look explicitly at only the entities and interconnections that are relevant to a specific research question, hierarchically informed data analysis has enabled a revolution in ecological understanding. With this new edition of Hierarchy, that revolution continues.