Arthur G. Tansley coined the word “ecosystem” to emphasize the need for ecological studies to integrate the living and nonliving parts of the environment.

In 1935, Arthur G. Tansley, a leading English plant ecologist, wrote a paper criticizing the pioneering ecological theory of his American colleague and friend Frederic E. Clements. John Phillips, a South African plant ecologist, had carried Clements’s ideas on the nature of the plant community to an extreme that Tansley found intolerable. Tansley responded with “The Use and Abuse of Vegetational Concepts and Terms,” “Use and Abuse of Vegetational Concepts and Terms” (Tansley)[Use and Abuse of Vegetational Concepts and Terms] which was published in the American journal Ecology. In that paper, Tansley suggested the term “ecosystem” to replace Clements’s “complex organism” and defined the new term to include both the living and the nonliving parts of the environment. He argued that plant interactions with the physical environment as well as interactions among plants determine community organization. He suggested that the ecosystem should be studied as the fundamental ecological unit. [kw]Tansley Proposes the Term “Ecosystem” (July, 1935)
[kw]”Ecosystem,” Tansley Proposes the Term (July, 1935)[Ecosystem, Tansley Proposes the Term (July, 1935)]
Ecosystem ecology
Ecological theory
[g]England;July, 1935: Tansley Proposes the Term “Ecosystem”[08930]
[g]United States;July, 1935: Tansley Proposes the Term “Ecosystem”[08930]
[c]Environmental issues;July, 1935: Tansley Proposes the Term “Ecosystem”[08930]
[c]Science and technology;July, 1935: Tansley Proposes the Term “Ecosystem”[08930]
[c]Biology;July, 1935: Tansley Proposes the Term “Ecosystem”[08930]
Tansley, Arthur G.
Clements, Frederic E.
Gleason, Henry Allen
Lindeman, Raymond L.

Tansley was an institution in British ecological research. He did important early work on plant communities and wrote influential botanical textbooks. In 1902, he started the first British ecology journal, the New Phytologist. He was instrumental in the establishment of the British Ecological Society in 1913 and served as the organization’s first president. He also played an important role in nature conservation in the British Isles.

Clements was a leading American ecologist, a pioneer in the formulation of a new science. He wrote an influential ecology text, coauthored an early attempt to integrate animal and plant ecology, developed a new, mathematically based system of vegetation analysis, and developed a historically important theory on the nature of plant communities. Plant communities He and his theory played important roles in early arguments for conservation of natural communities during and after the Dust Bowl tragedy of the 1930’s.

According to Clements’s theory, plant communities behave like complex organisms, with the different species as interdependent on one another as the organs within an organism. In addition, this organismic community has a specific and predictable developmental sequence (called ecological succession) that is analogous to embryologic development in an organism and that ends in a mature community (the climax community). Under a given set of climatic conditions, an identical climax community is reached at the end of every successional sequence. The sequence is predictable because of the intimate (organismic) interactions among community members.

Ecologists agreed that a given set of climatic conditions generally gives rise to a given type of vegetation and that a particular sequence of communities occurs in establishing this climax community. They disagreed, however, with Clements’s idea of nearly complete interdependence among community members, his insistence on identical climax communities under a given set of climatic conditions, and his lack of emphasis on the role of physical factors in molding community structure.

Henry Allen Gleason suggested an alternative explanation for the phenomena of ecological succession and climax: the individualistic model. According to this theory, each individual plant responds to physical and biological factors independently, and the climax community is made up of the plants that can grow and reproduce under the physical conditions at the site. Climate is a major factor in determining which plants can grow in an area, but soils, fire, and other physical factors are also important. Interactions among the living things that occur in the area play a role in community structure, but that structure is essentially determined by each species’ individual response to the physical environment. Similarly, the plants present at any given stage of succession are determined by which plants have reached the area by that stage and which plants grow best under the physical conditions present. The organization of a community is determined by individual plant characteristics, not by organismic plant interactions.

Tansley embraced many of Clements’s ideas, but he held to a less literal view of the organismic community. He saw Clements’s literal view as neither an accurate representation of natural communities nor a helpful framework for advancing ecological understanding. Phillips’s articles triggered Tansley’s direct attack on the literal organismic community; in that attack, he redirected ecological thought to the total system, in which the physical environment plays a larger role than it does in Clements’s organismic community. A word was needed to designate the community, its physical environment, and all the interactions between them.

The idea was not new, and several terms were already available. In 1883, Karl August Möbius had used the term “biocoenosis” to refer to the physical and biological interactions in an oyster bed. Stephen Alfred Forbes had used “microcosm” in 1887 to describe the same set of interactions in a lake. These are often cited as the earliest expressions of the idea. Rather than use one of the older terms, however, Tansley coined his own: “ecosystem.” The word and, more important, the idea it represented set the stage for elaborate studies, the results of which demonstrated the necessity of conserving entire ecosystems.

Tansley’s paper had little immediate impact, but the concept of the ecosystem gained acceptance over time. The ecosystem came to be viewed as an aggregation of plant, animal, and microorganismic species, each of which responds individually to its physical environment as well as to the other species sharing that environment. Community and ecosystem types are recognizable in nature (temperate deciduous forest, tropical rain forest, grassland, lake, and salt marsh, among others), but they merge gradually into one another, and a given ecosystem differs from one part of its geographic extent to another. Therefore, the community contained within the ecosystem is not a tightly integrated unit, an organism, but a group of species thrown together by their common ability to live under the available conditions. Once thrown together, the species must interact, and intimate (organismic) relationships sometimes develop between members of the community. The community’s organization is based on the individual species’ abilities to handle the physical conditions as well as these interactions.

Charles Elton, Elton, Charles a British animal ecologist working in the general context of Tansley’s earlier modification of Clements’s theory of community organization, had already developed models for the transfer of energy and matter through the components of biological communities: food chains, food webs, and ecological pyramids. Elton said that plants are eaten by and are more numerous than herbivores, which are in turn more numerous than the carnivores that eat them, and so on. This reduction in numbers with each link in the food chain (or feeding level in the pyramid) restricts the number of links in the chain (or levels in the pyramid), because after a few reductions there is not enough food to support the next higher link (or level).

Elton’s work inspired another British ecologist, G. Evelyn Hutchinson, Hutchinson, G. Evelyn who also worked within a modified Clementsian model, although he probably did not derive it from Clements directly. Hutchinson studied matter and energy flow through lake communities and introduced the idea of biogeochemical cycles in which nutrients (chemicals) move between the physical environment and the members of the community. Elton and Hutchinson, both working within modified organismic models, focused the attention of ecologists on the transfer of matter and energy from the physical environment through a series of community members back to the physical environment. These transfer events became the major topics of ecosystem ecology.

A student of Hutchinson, Raymond L. Lindeman, used Tansley’s ecosystem concept and Hutchinson’s methods in an analysis of the energetics of a lake ecosystem. Despite serious objection to his work by several established biologists, Lindeman’s resulting paper, “The Trophic-Dynamic Aspect of Ecology,” published in the journal Ecology in 1942, had a dramatic impact. His study served as a model and became a catalyst for similar studies of ecosystem energy relationships and helped establish the ecosystem as a fundamental ecological unit.

Lindeman’s paper was highly theoretical and was not based on extensive or particularly accurate measurements of ecological parameters. The technology of the time made such measurements difficult or impossible. Beginning in the 1950’s, Eugene P. Odum Odum, Eugene P. and Howard T. Odum, Odum, Howard T. both deeply influenced by Hutchinson, pushed ecosystem ecology to its next plateau. They ran a series of ecosystem studies on abandoned farmland around the Savannah River nuclear plant in Georgia, on the Pacific island of Enewetak (a site used for nuclear testing), on the mineral springs at Silver Springs, Florida, and at other sites. In each of these studies, they considered the energy flow and matter cycles of the entire system; they also developed new techniques for measuring such flows, most notably the use of radioactive isotopes to trace the flow of matter through a system.

In the 1960’s, thirty years after Tansley’s suggestion to consider entire ecosystems as units for ecological research, F. Herbert Bormann Bormann, F. Herbert and Gene E. Likens Likens, Gene E. began a series of studies in the Hubbard Brook Experimental Forest Hubbard Brook Experimental Forest in New Hampshire. These studies evolved into a multiyear study of the entire Hubbard Brook ecosystem and involved nearly two hundred scientists. The researchers measured inputs and outputs to individual watersheds and explored the watersheds’ handling of materials. They cut all vegetation from some watersheds and studied the effects. They also applied herbicides to some clear-cut watersheds and analyzed the long-term absence of plant cover. Bormann and Likens followed Tansley’s advice to study entire ecosystems, and their work resulted in significantly improved understanding of ecosystem organization and function.

An even larger-scale ecosystem study was also initiated in the 1960’s. The International Biological Program International Biological Program (IBP) was considerably more popular in Europe and Canada than it was in the United States, but even in the United States, its goals were in keeping with Tansley’s suggestion. These goals included gathering sufficient data from five major ecosystems—referred to as “biomes” by the IBP—to produce computer models of the structures and functions of each. Scientists could use these models to understand the biomes in greater depth and so better direct their management. In his paper, Tansley had suggested the use of mathematical models for improved understanding of ecosystems.

The IBP did not fulfill its mission to generate functional models of biomes, but it did stimulate elaborate and cooperative studies of whole ecosystems, and so contributed to the establishment of ecosystem ecology. The Ecosystem Studies Program of the National Science Foundation followed the IBP as the organization responsible for funding large-scale ecosystem studies, and such studies increased in numbers, indicating the perceived importance of ecosystem ecology. The sequence of events that established that importance was, in a sense, initiated by Tansley’s introduction of the word “ecosystem” in his criticism of Clements’s “organismic community.”

Once the ecosystem became established as the functional ecological unit, it became clear that conservation efforts could be successful only if they concentrated on conserving such units. Although community structure is not literally organismic, an intact ecosystem is required for continuity of many of its member species. In their day, both Clements and Tansley argued for the conservation of entire ecosystems. As researchers learned more about the structures and functions of ecosystems, their findings led to conservation efforts that attempted to save systems rather than species. Ecosystem ecology
Ecological theory

• Egerton, Frank N. “The History of Ecology: Achievements and Opportunities, Part One.” Journal of the History of Biology 16 (Summer, 1983): 259-310. An overview of the history of ecology, including ecosystem ecology. Commentaries on other sources are especially interesting. Includes extensive references.
• _______. “The History of Ecology: Achievements and Opportunities, Part Two.” Journal of the History of Biology 18 (Spring, 1985): 103-143. Continuation of the paper cited above deals with applied ecology in which ecosystem ecology has played an important role. Considers Clements’s arguments for conservation during the Dust Bowl era. Includes extensive references.
• Godwin, Sir Harry. “Sir Arthur Tansley: The Man and the Subject.” Journal of Ecology 65 (1977): 1-26. Brief biography of Tansley by one of his closest colleagues. Provides insight into Tansley’s personality and varied interests.
• Golley, Frank Benjamin. A History of the Ecosystem Concept in Ecology: More Than the Sum of the Parts. New Haven, Conn.: Yale University Press, 1993. Lucid history, chronologically arranged, on the evolution of the concept of the ecosystem. Chapter 2 places Tansley’s contribution in historical context. Includes extensive bibliography and index.
• Hagen, Joel B. An Entangled Bank: The Origins of Ecosystem Ecology. New Brunswick, N.J.: Rutgers University Press, 1992. Excellent history of ecosystem ecology. Includes illustrations and index.
• McIntosh, Robert P. The Background of Ecology: Concept and Theory. New York: Cambridge University Press, 1985. Excellent work places Tansley’s contribution in context. Chapter 6 specifically covers ecosystem ecology, but related ideas are discussed throughout. Includes bibliography and index.
• Pepper, David. Modern Environmentalism: An Introduction. New York: Routledge, 1996. Places key ideas concerning environmentalism in social and cultural context. Includes discussion of the ecosystem concept. Features figures, tables, glossary, and index.
• Real, Leslie A., and James H. Brown, eds. Foundations of Ecology: Classic Papers with Commentaries. Chicago: University of Chicago Press, 1991. Collection of classic papers presents wide-ranging information, and commentaries provide historic perspective. Includes the paper in which Tansley coined the term “ecosystem,” Lindeman’s paper, and related papers by Forbes, Clements, Gleason, Eugene Odum, and Likens and Bormann.
• Tobey, Ronald C. Saving the Prairie: The Life Cycle of the Founding School of American Plant Ecology, 1895-1955. Berkeley: University of California Press, 1981. An excellent source of information on the rise and fall of Clements’s organismic community model and its impact on the drought-stimulated conservation movement. Chapter 6 outlines Tansley’s criticism of Clements’s ideas. Includes illustrations, bibliography, and index.
• Worster, Donald. Nature’s Economy: A History of Ecological Ideas. 2d ed. New York: Cambridge University Press, 1994. Well-written history of ecology includes ample coverage of ecosystem ecology. Provides an interesting perspective on the concept of the ecosystem and its history.

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