British ecology from across the pond: counterpoint and cartharsis

By Michael A. Huston, Texas State University, San Marcos, Texas, USA

Professor in the Biology Department at TSU, Michael has published on a range of topics related to biological diversity, including tropical rain forests, coral reefs, plant succession, competition, and invasive species. He is best know for his theories on the regulation of species diversity, and for his book, Biological Diversity, published by Cambridge University Press in 1994.

Ecology has developed a different ‘flavor’ on different continents, at least partially because of differences in environmental conditions. The density-independent, disturbance-driven concepts of Andrewartha and Birch, which were developed in the unproductive and drought-prone ecosystems that cover much of Australia, were often seen as conflicting with the more deterministic, competition-driven ideas of American ecologists who worked in the productive grasslands and forests of North America. British ecology, developed on a landscape without the great extremes of conditions seen in Australia or North America, was more nuanced, focusing on the details and mechanisms underlying more subtle variations in vegetation.

By mid-century, each continental school of ecology had its Founders and its Giants. Arthur Tansley was certainly the first Giant of British Ecology, and ranks among the global Giants of Ecology in terms of his lasting impact on the field around the world, even though many young ecologists do not recognize his name.

It is noteworthy that one of Tansley’s many contributions was the organization of first International Phytogeographic Excursion (I.P.E.), a four-week field trip around the British Isles that brought together British and Continental ecologists, as well as the two Giants of American Ecology, Frederick Clements and Henry Cowles. This was followed by a second I.P.E., this time lasting two months in the United States, hosted by Henry Cowles.¹¹⁰ While it is difficult for most of us to envision finding this much time to tour ecosystems with our colleagues, the multiple I.P.E.s that were conducted from 1911 through the 1930s, must have had a tremendous impact on the transmission of information, the development of ideas, and international good-will and friendships among ecologists.

The value of comparisons of ecological patterns across many different environmental conditions cannot be overestimated. Comparisons of this type were clearly critical to the insights of Charles Darwin and Alfred Wallace, and continue to play a major role in the development of new ecological ideas today, including whatever insights I may have had. Arthur Tansley clearly recognized this, and promoted this comparative phytogeographic approach in the early days of ecology.

Giants in a field, as influential as they may be, are rarely perfect. One of the greatest Giants of American Ecology was Frederick Clements, whose prodigious research program and comprehensive publications on such major topics as Competition and Succession provided the foundation for American and Global Plant Ecology. Unfortunately, Frederick Clements was also the author of what is now one of the most ridiculed ideas in the history of ecology, the concept of plant communities as a super-organism, which is perceived by many as an embarrassment to American Ecology. What began as a reasonable metaphor in his 1916 masterpiece, Plant Succession,¹¹¹ evolved into a dogma as the parallels between the organismal development and plant community development were codified and exaggerated.

By the early 1930s, Tansley’s own work and ideas on plant succession were well-known and quite influential. However, in 1934 and 1935, a series of publications by John F.V. Phillips, a South African ecologist with extensive experience in the forests and savannas of southern Africa, motivated Tansley to respond forcefully to a metaphor that was taking on a life of its own.

Phillips’ own motivation, and his interest in Clements’ super-organism concept, seems to have come from his recognition that ecological concepts at that time were not particularly clear or useful for understanding patterns in nature. This was inhibiting progress in the field of ecology, as well as the recognition of ecology as a legitimate scientific field. He was clearly striving to generalize and identify unifying concepts in ecology:

‘Criticism, destructive and constructive, acts as an elixir upon the ecologist, forcing him to re-examine the bases of his suppositions and beliefs. During the last five years I have frequently been cross-examined, verbally, and by letter, as to certain of my views regarding plant ecology in South and East Africa, as well as upon the tenets of leading workers such as Clements, Tansley, and members of the phyto-sociological schools of Europe. Perhaps an especially remarkable feature of criticism received has been that it has come largely either from those who are neither botanists nor ecologists, or from assistants and students in the course of training for ecological work. I submit, therefore, to professed ecologists, that our concepts may be shrouded in nebulous covering in our literature – due doubtless to our admitted lack of certainty and agreement.’ ¹²⁸[p.353]

Phillips followed this paper with Parts II¹²⁹ and III¹³⁰ in 1935 in the Journal of Ecology, with 57 more pages of review and argument supporting the concept of plant communities as a complex organism.

Arthur Tansley took the opportunity of an invitation to contribute to a special issue dedicated to Henry Cowles in the American journal, Ecology, to write the definitive critique of the super-organism concept. This paper is now Tansley’s most highly cited journal paper, and is included in the influential 1991 compendium Foundations of Ecology: Classic Papers with Commentaries.¹³¹

It is doubtful that Phillips particularly enjoyed the ‘elixir’ of Tansley’s criticisms, but Tansley crafted a masterful, gentlemanly dissection of the semantics and logic of the super-organism concept in his paper, The 'use and abuse' of vegetational concepts and terms.⁵⁵ Tansley’s criticisms focused on ideas, not people, although the ideas were closely tied to Clements and his followers. Nonetheless, the generous compliments and the restraint shown by Tansley are reminiscent of the gentle collegiality of Charles Darwin, as revealed in his correspondence. Tansley wrote,

If some of my comments are blunt and provocative, I am sure my old friend Dr. Clements and my younger friend Professor Phillips will forgive me. Bluntness makes for conciseness and has other advantages, always provided that it is not malicious and does not overstep the line which separates it from rudeness. And at the outset let me express my conviction that Dr. Clements has given us a theory of vegetation which has formed an indispensable foundation for the most fruitful modern work. With some parts of that theory and of its expression, however, I have never agreed, and when it is pushed to its logical limit and perhaps beyond, as by Professor Phillips, the revolt becomes irrepressible. But I am sure nevertheless that Clements is by far the greatest individual creator of the modern science of vegetation and that history will say so. For Phillips’ work too, and particularly for his intellectual energy and single-mindedness, I have a great admiration.
Phillips’ articles remind one irresistibly of the exposition of a creed – of a closed system of religious or philosophical dogma. Clements appears as the major prophet and Phillips as the chief apostle, with the true apostolic fervour in abundant measure. Happily the odium theologicum is entirely absent: indeed the views of opponents are set out most fully and fairly, and the heresiearchs, and even the infidels, are treated with perfect courtesy. But while the survey is very complete and almost every conceivable shade of opinion which is or might be held is considered, there is a remarkable lack of any sustained criticism of the opponents’ arguments. Only here and there, as for instance in dealing with Gillman’s and Michelmore’s specific contentions, and in a few other places, does the author present scientific arguments. He is occupied for the most part in giving us the pure milk of the Clementsian word, in expounding and elaborating the organismal theory of vegetation. This exposition, with its very full citations and references, is a useful piece of work, but it invites attack at almost every point.’⁵⁵[pp.285-286]

Following this introduction, Tansley went on to discuss and clarify the major concepts in plant ecology, addressing in turn, ‘Succession’, ‘Development and the Quasi-organism’, ‘Climaxes’, ‘The Complex Organism’, ‘The Ecosystem’, Biotic Factors’, and ‘Methodological Value of the Concepts in Relation to Successional Change’. This paper should be read by all ecologists, both for its content and its style.
For this contribution, American ecologists owe Arthur Tansley a debt of gratitude. Tansley struck a mortal blow to the Superorganism Concept, and did much to distinguish the very important and influential work of Clements from his unfortunate excess in one area. Sadly, most young ecologists today think of Clements as an old fool with absurd ideas, and are not aware of his tremendous contributions. Neither are they likely to be aware of the fundamental contributions of Arthur Tansley.

Reading the work of both of these great men, it is humbling to realize how much they understood about the natural world, and how little new information and few new ideas have been added in the past eighty years. Much of what is published today only seems new because most ecologists today are ignorant of how much was understood by the pioneers in the field. Giving a new name to an old idea does not constitute scientific progress, even if the originator thinks he was the first to figure it out.

The last words shall come from John Frederick Vicars Phillips (1899-1988) who provided the motivation for Arthur Tansley’s cathartic contribution to American Ecology.

‘...it seems plain that co-operative or team work is essential; botanists, zoologists, workers in other sciences must labour together, and link up with men of practice and administration. The field is too wide for any single worker – the investigators of the biotic community must be inspired “to set the cause above renown, to love the game beyond the prize” – a sentiment as yet none too common in circles ecological.’¹²⁷[p.21]