The History of the Ecosystem Concept

Part 3. Post-WWII Ecology
The Odum Brothers

It is not an understatement to say that Eugene P. Odum, along with his brother Howard (Tom) Odum, have been the two most important ecologists of the 20th century. E.P. Odum was born in 1913. His father was a professor of sociology at UNC-Chapel Hill (Howard Washington Odum). As Hagen points out (pg. 123) Eugene's father had embraced the concept of holism, which he passed on to his son and which influenced E.P. Odum's approach to ecology thereafter. Odum decided to pursue a Ph.D. at the University of Illinois, where strange as it may seem, he worked on the physiology of heart rates in birds with Charles Kendeigh, a physiological ecologist. The chair of his department was Victor Shelford, who at the time was completing his book, Bio-Ecology, and who later would write the classic The Ecology of North America. Thus, Eugene was exposed to ecology from the start, and the large group of graduate students in the department provided the opportunity to discuss the most exciting ideas of the time.

Odum later remarked that his transition from the physiology of the individual to ecosystems was a natural one, since as he put it, its not such a big step to go from physiology on one level to physiology on the ecosystem level. With help from his younger brother Tom, who was finishing up a Ph.D. with Hutchinson, E.P. Odum actually made this transition after accepting a position with the Atomic Energy Commission. In fact, while Tom Odum was at Yale, he used to send his brother Hutchinson's lecture notes, which over the years eventually led to a correspondence building up between E.P. Odum and Hutchinson. Hutchinson's influence in Odum's later textbook becomes evident once this connection is known.

The two Odums could not be more different in personality and approach to ecology. Eugene retained the more traditional ties to biology and physiology, whereas Tom Odum, with a stronger background in the physical sciences, more often approached ecology from a physical and mechanical point of view. In personality, Eugene is your typical southern gentleman, whereas Tom is brash, outspoken, and regarded somewhat as the 'enfant terrible' of ecology. I remember back in the early 1990's when I organized a symposium at the Ecological Society of America Meetings in San Antonio, and I had asked Eugene Odum to be the first speaker in the symposium. The topic was Ecological Economics, and both Odums have had a strong interest in this field. After getting E.P. Odum's acceptance to speak, I next sought Tom Odum, to get some contrast between the two brothers. Well, I can still recall Tom's response, who, once I told him that his brother would also be speaking, sharply stated: "I don't want to speak at the same conference that my brother is speaking at. He'll do a good job. Thank you. Goodbye."

Well, personal problems prevented Eugene from attending, and this happened just a few days before the symposium (his wife had died earlier and now his son had died of cancer). So, while standing in line to register for the meetings, I realized that the big, red-haired person in front of me was Tom Odum. So I struck up a conversation and eventually asked whether he might substitute for his brother at the symposium. In person he was much kinder and polite than on the phone, and he graciously accepted my invitation. In fact, he then pulled out a sheath of papers, and showed them to me and asked if this would do (it was a prepared talk on ecological economics!) and I said yes. So, Odum spoke at my symposium, and gave what people said was a great talk!

Tom Odum was particular influenced by the writings of Alfred Lotka, who wrote a book called Elements of Physical Biology. The systems approach was appealing to Odum, who later made it the mainstay of much of his research. Odum also attempted to incorporate evolutionary thinking into his research, looking for patterns that may have arisen by natural selection, but at the ecosystem level. According to Lotka, evolution was not just species changes through time, it was an overall accumulation and distribution of energy within a system. Natural selection tended to maximize the flow of energy and matter through a system, a concept little dealt with by traditional evolutionary ecologists, perhaps because most of them work at the level of the individual and population, and not the ecosystem. Odum took Lotka's idea and called it the 'maximum power principle', and it became the cornerstone of the bulk of his research. In the 1980's he produced a monumental textbook, Systems Ecology: An Introduction, which summarized his life work and how he approached the study of ecosystems.

As Tom Odum was finishing his dissertation, his older brother Eugene was completing the first edition of his textbook, Fundamentals of Ecology. The chapter on energy, however, was written in large part by Tom Odum, and their collaboration, which complemented their two approaches to ecology, resulted in the best selling ecology textbook ever. Eugene Odum's skills as an ecologist notwithstanding, his abilities to grasp complex ideas and write about them in ways that were understandable to younger scientists and students is one of his enduring legacies. Odum achieved this remarkable writing ability through the clever use of analogies, some very Clementsian in form, and by his ability to sift through the morass of details and pull out the important concepts. In addition, and no less important, he was not shy about making dogmatic synthetic statements, and by creating new hypotheses, some of which both infuriated and stimulated other ecologists. This combination of intellectual acuity and boldness established Eugene as an ecologist to be reckoned with.

Once Eugene was established at the University of Georgia, where ecology was not yet a tradition, he began to take advantage of the situation around him. He saw great potential for ecosystem research in coastal systems, and was instrumental in setting up Georgia's marine biology station on the island of Sapelo. He had begun to do some work down on the marsh, and became friends with the owner, R.J. Reynolds, who later donated the island to the state as a preserve, and the inholdings became the initial laboratory and administration buildings. At the same time, Odum was attracting highly talented and bright new researchers in the field of ecosystem ecology. John Teal, who had finished a two year study of a spring ecosystem (which was only 2 meters diameter!) was brought in to help set up and run the fledgling research program on Sapelo.

About two hours drive from UGA is the Savannah River Nuclear Plant, the largest civilian construction project since the Panama Canal. As at other nuclear sites, much of the land surrounding the production facilities was left idle, both for security purposes, and because it wasn't directly needed for the generation of nuclear products. Odum took advantage of this and in 1951 began a long-term study of succession, always a strong interest of his, on the unused portion of abandoned land on the plant. The government had moved the locals off the land when construction began, and their fields were undergoing succession.

Starting off with just trailers and a small budget, Odum built up the lab (which, incidentally, is where I worked on my dissertation) into a facility which today employs 50-100 people on a nearly $10M budget. In fact, some of our graduates have ended up being employed at the lab, now known as the Savannah River Ecology Lab. On campus, Odum started the Institute of Ecology, which actually directs the work at Savannah River, and attracted a large group of ecologists with interests in ecosystem ecology, including but not limited to Frank Golley, Dac Crossley, Bernard Patten, Richard Wiegert, Carl Monk, Carl Jordan, Becky Sharitz, Mike Smith, and Whit Gibbons. All of these scientists came to UGA in the late 1950's to the mid 1960's, when ecosystem ecology was peaking as a new discipline. Now, the Institute has evolved to include the Department of Ecology at the University of Georgia, and E.P. Odum still comes to his office, where he is now professor emeritus. Both he and his brother have won just about every award possible, including the prestigious Crafoord award, given for outstanding achievement in ecology and the environment, and the Tyler Award, which is as close to a Nobel as an ecologist is going to get.

What was it that the Odum's did to get ecosystem ecology going so vigorously?
E.P. Odum believed in the concept of homeostasis, that ecosystems developed and eventually achieved a situation in which homeostasis prevailed. This was not simply a restatement of Clements' views, but a refinement, since Odum considered that the parts that made up the ecosystem (cells, organisms, populations) each had self-regulatory properties, that when working together in a system, propelled it towards homeostasis. Individuals and populations had roles to play in the ecosystem, and it was the ecologists' duty to figure what those roles were.

While Eugene pursued a more physiological approach to ecosystems, his brother Tom was attempting to apply physical systems modeling to ecosystems. Odum believed that natural selection favored systems that maximized power output in the form of growth, reproduction, and maintenance. This also meant that systems did not always move towards greatest efficiency, since maximum power was not always a result of maximum efficiency. In addition, natural selection would result in more stable ecosystems, with increasing amounts of energy devoted to maintenance: photosynthesis was completely balanced by respiration.

In a landmark study, the Odums studied a coral atoll in the Pacific, courtesy of atomic bomb testing, and their work, published in Ecological Monographs in the 1950s, was one of the first complete studies of an ecosystem at work. In fact, the Odums approached it so completely from an ecosystem point of view, that they didn't even know most of the organisms they were studying! But they did find that this apparently stable system was in an apparent state of homeostasis, and that almost all energy was used for maintenance, rather than growth and/or reproduction.

Table 9.1 from Odum's 3rd edition of his textbook shows the major trends in ecosystem development that he thought would happen. While many of these trends have been shown to be wrong, the important point is that this table, derived from his controversial 1969 paper in Science, The Strategy of Ecosystem Development, which was based on his 1966 Presidential Address to the Ecological Society of America, stimulated lots and lots of research. Sometimes it is isn't that you get everything right, but that you took the risk, stuck your head out, and pushed the science ahead. Odum was not afraid of doing just that, and as a consequence, was able to push ecosystem science to where it is today.

Meanwhile, Tom Odum was also writing a book, Environment, Power, and Society (1971). This book, which actually was written for a semi-lay audience, became quite popular, but was never fully accepted by ecologists, perhaps, as Hagen notes, because of his foray into sociology and religion, which many found too speculative and idiosyncratic. But it did show how this Odum regarded ecosystems as physical systems to be studied, and represented the culmination of many years of work in this area. It also was one of the first books to warn about the dangers of rampant industrialism, using systems analyses to show how and where the impacts would occur.

Big Time Ecology
During the 1960s, when the Odums were at their creative peaks, other scientists were organizing large-scale research efforts to understand the world's major ecosystems. With administrative offices centered in England, scientists from around the world began working in groups to study major ecosytems, such as forests, grasslands, tundra, and so on. In the United States, these efforts began from funding that was originally from the AEC, then later from NSF, and the program was known as the IBP (International Biological Program). George Van Dyne was the head of the first endeavor, a study of midwestern grasslands. Van Dyne was only 35 when picked to head this project, arriving from Oak Ridge, which had already begun establishing itself as a center for systems ecology, primarily because of the massive computing power onsite. Van Dyne recruited researchers to work on the grassland project, and was very instrumental in getting a team to work as a coherent group.

However, this was not an easy task, because most ecologists were an independent lot, and not used to a hierarchical scheme of assigning tasks, or of reporting to a "boss" so to speak. This meant that harmony was not always present, and after a number of years, people began leaving the project. At the same time, other IBP projects were being established, but suffering the same kinds of problems. Eventually, the IBP program was closed in the mid-1970s. Van Dyne, who was a prolific researcher and administrator, lost control of the project near the end, and died of a heart attack at age 49.

At the same time as the IBP program was gearing up, two researchers in the northeast, Gene E. Likens, and F. Herbert Bormann, were beginning a study at Hubbard Brook, a U.S. Forest Service hydrological research site. Likens had a hydrology/limnology background, while Bormann got his undergraduate degree from Rutgers (with Murray Buell, a prominent plant community ecologist) and his Ph.D. from Duke, where he worked with H.J. Oosting. Bormann, who at this time was at Dartmouth, recognized that the Hubbard Brook site was ideal for studying ecosystems, and more importantly, for testing ideas about ecosystem development and functioning.

Hubbard Brook is a set of watersheds, underlain by bedrock. Bormann realized that all the water that fell on the site either had to be evaporated or transpired away by the plants and other surfaces, or it came out in the stream water at the bottom of the watersheds. No deep leaching could occur. In addition, if one measured the amount of water entering, and that leaving in the streams, and one knew the nutrient concentrations in that water, you could calculate the mass flux of nutrients entering and leaving the system. Thus, HB offered a unique opportunity to study biogeochemical cycling on a grand scale. Further, with the assistance of the Forest Service, and a suite of graduate students and visiting researchers, this team of scientists realized they could do ecosystem research outside the constraints of the IBP program.

In 1963, with just a few thousand dollars seed money, Bormann and Likens began the Hubbard Brook Ecosystem Study, which would later expand into a much larger and significant project, which we will study later in this course. This project resulted in many significant papers, and produced a number of prominent researchers, who obtained their degrees working on this site. It also turned out to be much more cost efficient than the IBP program. Bormann attributed this to the camaraderie and style of management, which although team oriented like the IBP, nevertheless allowed each researcher more of their own space and recognized the benefit of individuality. As a result, people wanted to come and work at Hubbard Brook, and productivity was kept very high. It is now recognized as the prototypical ecosystem research style, and is perhaps the most widely known ecosystem study ever done.

Bormann and Likens showed that big time ecology could be done without having to have a large infrastructure, and that for studies concerned with biogeochemical cycling, that the watershed was the ideal unit. Their work, much imitated in other areas, has become the de facto model for how modern ecosystem ecology is done.

I was privileged to know Herb Bormann for the two years I was at Yale, where he moved after his stint at Dartmouth, and I saw the research going on at HB. During the time I was at Yale was when Bormann and Likens first published their observations on acid rain, constituting one of the first reports that acid rain was happening in the U.S., and its potential adverse consequences. It was an exciting time, and I was happy to be a part of it, even so peripherally as simply being a student there, and not one of the active researchers.

Well, this completes our extensive survey of the history of ecosystem ecology.