this book presents a hierarchical concept of ecosystems, proposing a theory that integrates ecological systems with the principles of hierarchy. the authors, r. v. o'neill, d. l. deangelis, j. b. waide, and t.f.h. allen, explore the fundamental ambiguities in the ecosystem concept and provide a historical perspective on how ecologists have viewed ecosystems. the book is divided into four parts: the concept of an ecosystem, preliminary considerations, a proposal for a theory, and applications of the theory to ecological systems. in part i, the authors discuss the ambiguities in the ecosystem concept and its historical development. part ii covers preliminary considerations, including the ecosystem as a system and the concept of hierarchy. part iii proposes a theory of hierarchy, discussing elements of hierarchy theory and how hierarchical structure arises from evolution in open, dissipative systems. part iv applies the theory to ecological systems, examining ecosystems as hierarchies of species, processes, and dual hierarchies. the book includes a list of literature cited, an author index, and a subject index. the authors aim to provide a comprehensive framework for understanding ecosystems through the lens of hierarchy, integrating ecological concepts with theoretical principles. the book is intended for ecologists and other researchers interested in the structure and function of ecosystems.this book presents a hierarchical concept of ecosystems, proposing a theory that integrates ecological systems with the principles of hierarchy. the authors, r. v. o'neill, d. l. deangelis, j. b. waide, and t.f.h. allen, explore the fundamental ambiguities in the ecosystem concept and provide a historical perspective on how ecologists have viewed ecosystems. the book is divided into four parts: the concept of an ecosystem, preliminary considerations, a proposal for a theory, and applications of the theory to ecological systems. in part i, the authors discuss the ambiguities in the ecosystem concept and its historical development. part ii covers preliminary considerations, including the ecosystem as a system and the concept of hierarchy. part iii proposes a theory of hierarchy, discussing elements of hierarchy theory and how hierarchical structure arises from evolution in open, dissipative systems. part iv applies the theory to ecological systems, examining ecosystems as hierarchies of species, processes, and dual hierarchies. the book includes a list of literature cited, an author index, and a subject index. the authors aim to provide a comprehensive framework for understanding ecosystems through the lens of hierarchy, integrating ecological concepts with theoretical principles. the book is intended for ecologists and other researchers interested in the structure and function of ecosystems.