Teaching: A Canon for Plant Ecology
Plants are important. Plants feed all of humanity. Plants provide food and shelter for nearly all wildlife. Plants even regulate the climate by reducing greenhouse effect. More than 99.9 percent of the biomass on Earth is plants (Whittaker 1975), comprising somewhere between 3.1 and 4.2 x 105 plant species, of which 1/3 to 1/2 are at risk of extinction (Pitman and Jørgensen 2002). That we understand and appreciate plants is an imperative for human survival. Yet an early father of plant ecology, Sir Arthur Tansley (1951), lamented that “A good many of the papers published during the first years of the new century were … rather trivial and some of them decidedly slovenly.” (p. 6) Enormous amounts of work have been published since Tansley, and particularly since the 1970s. The challenge now is synthesis – we need to organize this work, and provide a logical structure for new generations of students. There are two obstacles to preparing such a synthesis: balkinzation and tyranny.
Obstacle 1: Balkanization.
Over the past century, ecology (and plant ecology) has fragmented into many sub-disciplines. This is partly a sign of progress; as a discipline grows, it inevitably demands more specialization. But I have used the older word Balkanization, because it better illustrates how a thriving multicultural society can fragment into small antagonistic states ruled by petty warlords.
Plant ecology has become similarly fragmented? by level of organization, by habitat type, by organism, by geographic region and even by nation. In wetland ecology (which itself is a ghetto of sorts) the mire ecologists are largely unaware of advances by marsh ecologists, the saltmarsh ecologists rarely cite work on freshwater marshes, and none of the foregoing seem aware of the progress in, say, chalk grasslands. Similarly, those who study competition or herbivory in one geographic region rarely cite those who study competition or herbivory in another, and vice-versa. I can’t begin to enumerate the number of maps I have seen that end abruptly at national boundaries, as if plants and animals needed passports. It is time to unify the discipline with important theories illuminated by classical experiments and patterns. To return to Tansley (1951) “it is the unifying point of view that makes ecology what it is.” (p.16).
Obstacle 2: Tyranny
It is difficult to assemble general principles when they have to apply to 3.0 x 105 species. A tempting alternative might be a charismatic leader to provide simple generalizations and then enforce their application. But history shows that a strong leader can easily metamorphose into a demagogue, and then into a tyrant. The Romans, for example, facing fragmentation and civil war, welcomed Caligula to the throne of imperial Rome in 37 AD. They understood the value of unification. But eventually Caligula began to give the Senate orders and “exact an Oriental subservience. He let senators kiss his feet in homage, and senators thanked him for the honor” (Durant 1944 p. 266) and soon he began “a reign of terror enhanced by his maniac joy of inflicting pain” (p. 267), instructing his executioners to kill victims with numerous slight wounds. He finally proclaimed his horse a priest and himself a god. Caligula is a useful point of reference in human behavior because he is a limiting case? he illustrates the dictum that power corrupts, and absolute power corrupts absolutely.
Tyranny can equally be found in academe. Camille Paglia (in her essay titled Junk Bonds and Corporate Raiders: Academe in the Hour of the Wolf) describes how one French writer, Foucault, became a veritable god-emperor, surrounded by American sycophants. “The elevation of Foucault to guru status by American and British academics is a tale that belongs in the history of cults.” (p. 174) The multiple problems included “false claim to novelty” (p. 172), “the strategy of obliterating distinguished past scholarship” (p. 176), “reinventing the wheel as a bone-jarring square” (p. 202), “ a diversion of professional energy away from study and towards performance, networking, advertising, cruising, hustling, glad-handing, back-scratching, chit-chat, group think” (p. 221). She concludes “The palace has been taken over by shallow upstarts, raiding and wasting the treasury laid up by so many noble generations.” (p. 248)
Closer to home, Ernst Mayr (1982) describes the case of Karl Wilhelm von Nägeli, a Swiss botanist of the 1800s who studied inheritance and development. For 20 years thereafter, says Mayr, one does not find a paper that does not quote him extensively and usually with “considerable reverence …. Nevertheless, almost every detail of his theory was radically wrong and almost none of it was based upon any known fact.” Not only did Nägeli decline to encourage Mendel, he ignored him. “When Nägeli in 1884 published his great book on evolution and inheritance, he entirely failed to mention Mendel even a single time …” (p. 723). Nägeli was, in Mayr’s words, skillfully able to wrap himself in the “right words” for the time, and often boasted about how his work involved a strictly mechanistic theory. Mayr adds, “Such claims were purely psychological weapons” (pp. 851-852).
A growing literature expresses concern about the degree to which plant ecology is being distorted by a new Nägeli (e.g. Shipley and Peters 1990, Huston 1997, Wardle et al. 2000, Grime 2002, Stohlgren et al. 2003), even to the strident insistence upon mechanistic theories. I have explored the problem in some detail myself elsewhere (Keddy 2001 pp. 33-35; 196-199; 358-359; 398-402). My objective here is to counter-balance the imperial view of ecology, and to promote respect for the many colleagues who built the discipline over the last century.
The Imperial Era
Different points of view are essential to progress in science. Mutual respect among colleagues is possible. But increasingly, a few loud voices are overwhelming reason and precedent. Plant ecologists have experienced the consequences ? careers sidelined, colleagues exiled, manuscripts and grants rejected out of hand? much as Caligula murdered or exiled rivals for his throne. The result has been a growing published fantasy world, increasingly detached from botanical reality. Reality comprises early studies of competition, Takhtajan’s studies of biogeography and evolution, Whittaker’s studies of dominance and diversity, Huston’s studies of disturbance, Harper’s studies of plant life history, Pielou’s null models for species distributions along gradients, Silvertown’s studies of long term changes in the Park Grass experiments, and Grime’s exploration of diversity and strategies (to name but eight). In contrast with these, in a still-expanding hallucinogenic realm, topics like competition, resource depletion, disturbance, diversity and function have allegedly each been re-discovered, and are released as new theoretical advances, fodder for headlines in Science and Nature.
Curiously, this has been aided by personages well outside the domain of plant ecology – a curious situation somewhat as if Caligula had been installed in Rome by the Carthaginians rather than the Roman Senate. Perhaps these scientists, largely zoologists and modelers, believe that so long as they cite, say, Tilman, they have done their bit and need not (mercifully) think or read further about plants. This is not a vulgar exaggeration. Recall Hutchinson’s 1959 paper “Homage to Santa Rosalia” (in The American Naturalist) where he says up front (at least he was honest) that his objective was to explore biological diversity without having to make the effort to consider plants. “[W]hy are there so many kinds of plants? As a zoologist I do not want to ask that question directly. I want to stick with animals but also get the answer.” Sir Robert May’s 1988 paper in Science “How many species are there on Earth?” had but a single (and unreferenced) mention of plants and fungi. Abramsky and Rosenzweig’s 1984 paper in Nature was boldly titled “Tilman’s predicted productivity-diversity relationship shown by desert rodents”. Readers of Nature might not know that behind this headline were earlier (and one might even suggest, better) models predicting the identical pattern? Grime in Nature in 1973 (1973 for heaven’s sake, not to mention his book in 1979) and Huston in The American Naturalist in 1979. More recently, Ecology published 16 self-congratulatory pages (and a front cover figure) in which Naeem (2002) applauds Tilman, himself and Loreau (8, 10 and 4 papers, respectively) upon “the emergence of a new paradigm, one in a series of debates associated with the dialectic that has structured ecological inquiry over two millennia of western Science” (p. 1537). Caligula metamorphosed from a welcomed ruler in 37 AD to a tyrant and god in less than four years. Plant ecology’s emperor has now become an immortal figure in two millennia of western science.
The consequence? Students are increasingly fed a grotesque view of reality, turning the real history of the past 25 (and 100) years of ecology into a soap opera “The emperor learns plant ecology”. In this melodrama, resources, competition, disturbance, productivity, biodiversity and function are each revealed as exciting new paradigms, soon to be headlines in Nature in a library near you. Increasingly, I review manuscripts that have only the most trivial treatment of the scientific literature, as if some authors now believe that one man single-handedly invented our discipline. Perhaps it is not their fault – they tend to read what is cited, and they cite what they read. Unless someone re-directs students to the facts of the discipline, how can we criticise their being distracted by Hollywood pyrotechnics?
Is there a middle way?
The television culture of the United States, now spreading to the West in general, seems increasingly to emphasize personalities over ideas, just as Hollywood films use explosions and car chases to cover weak stories. We may now be witnessing the diffusion of this approach into ecology. The tenets of science are intended to guard us against such delusions. One tenet, a familiarity with the scholarly literature, normally inhibits self-delusion, while promoting modesty and respect for others. A second line of defense lies in the tenet that all theories must be independently tested by objective colleagues. In the absence of these tenets, weak and fanciful ideas proliferate, inundating the strong work, leaving only political criteria for sorting among competing views of reality.
These tenets also protect us from ourselves. Of Caligula, Durant concludes “A quiet life of responsible labor might have steadied him, but the poison of power made him mad. Sanity, like government, needs checks and balances; no mortal can be omnipotent and sane.” (p. 266)
One could further argue that certain kinds of science are particularly vulnerable – these would include vast computer models and enormous extrapolations from small quadrats to global processes. Precisely because of the difficulty of falsifying such ideas, precisely because they are so far removed from the reality of real vegetation, such work might be considered to be more a fantastical art form than a science. Perhaps that is why Paglia's critique of the humanities (above) resonates with some of us in the sciences. Painting too is a realm where falsifiability is not a criterion, a realm known for vibrant colors, personal eccentricities, massive installations, and posturing. Consider the "Matisse-Picasso" exhibition, recently moved from the Tate Modern in London to the Metropolitan Museum of Art in New York. Jed Perl (2003) laments the “star-system art world of our day” in which “the faddists who control the art world …would not know a good painting from a bad one …”. Important developments in the field “are downplayed in favor of shows of bravado and egotism, of face-offs and rip-offs.” (p. 34). The “extraordinarily complicated landscape of twentieth century art” (p. 36) has been reduced to superficial treatment of a few personalities and “the museum's most vociferous supporters are so armored in their simplistic assumptions …that they are incapable of seeing what the museum has become” (p. 38).
Books, like reviews of art, assume special responsibilities. Authors must draw upon their own experience, sort through conflicting published opinions, and present a synthesis with a close fit to reality. Unlike reviewers of art, they have criteria including measurability, data quality, repeatability, consistency, statistical significance and common sense. Am I alone in suspecting that important ecological books, books that could dampen authoritarianism and emphemeralization, increasingly remain unread (and uncited) -- generating a positive feedback loop with negative consequences? Am I alone in suspecting that younger authors write down a word like ‘disturbance’ or ‘function’ in their on-screen manuscript, and then hurriedly turn to the web for a few quick, easy and recent titles of short papers using that word in the title? That consequently they never encounter, say, Pickett and White’s (1985) classic overview of disturbance, nor de Groot’s (1992) thorough compendium on function? Is that also why I routinely hear words like ‘disturbance’ and ‘function’ abused in presentations? If this continues, ecology will be staggering in a random walk led by the whims of one self-intoxicated grand marshal, all guideposts of historical accuracy having faded from memory.
Offering a canon for plant ecology may be one positive way to restore a semblance of order to our discipline. I have for decades admired the courage of Mortimer J. Adler, who offered in 60 volumes, the Great Books of the Western World, a canon for western literature stretching from Homer to Beckett. What would such a canon look like in ecology? Could one present such a list without being accused of arrogance? I posted a preliminary list for plant ecology on my web site in 1999, without much reaction. I now expand the list and share it you. I fully admit that it is one person’s perspective -- but to judge from the complaints of the moving company who carried my belongings to Louisiana, I have more books than most. And so I have sifted through my collection to offer a first draft of the canon for (plant) ecology. I say “(plant) ecology” in the hope that with a few obvious exceptions, the same list will work for colleagues who work with animals.
My criteria were straightforward: assuming that most students and young professors are short of money, what would be the fundamental list of books that they should read and eventually acquire. I started with only four criteria:
Only five books on the final list were edited compendia. Far too often, it seemed, compendia reflected political connections in academe rather than objective treatments of a discipline. Further, in multi-authored works, important topics are frequently omitted (perhaps because each author assumes another will cover it, perhaps because many more people study some phenomena (e.g. birds, lizards) than others (e.g., macro fungi, cycads). There is good news for aspiring authors -- in a world with a scientific literature that grows exponentially, there continues to be a place for those few individuals willing to read widely and put the pieces together. The bad news is that enormous numbers of books are published, and there is room for only a few dozen, by definition, in a canon. Hence, many good books, well worth reading and owning, had to be omitted. I beg the forgiveness of any authors who feel slighted, and I welcome your input through letters building the case for new inclusions or arguing against some on the following list.
Here, then, are 19 essential books, and 23 others, for a total of 42 books needed in a young professional's library on plant ecology. The main list is preceded by three others: origins and history of the biota, historical context (books out of date but valuable for their historical perspective), and popular/environmental (books that provide the social container for the technical works). I have cited the editions that I own – many exist in multiple editions, and I do not mean to imply that mine are the best available.
1. Darwin, C. 1859. The Origin of Species by Means of Natural Selection. In Great Books of the Western World, Second Edition, (M.J. Adler, 1990) Vol. 49, Encyclopaedia Britannica, Chicago.
2. Takhtajan, A. 1969. Flowering Plants: Origin and Dispersal. Oliver and Boyd, Edinburgh. Tranlsated and revised from a Russian second edition published in Moscow in 1961.
3. Willams, G.C. 1975. Sex and Evolution. Monographs in Population Biology. No. 8. Princeton University Press, New Jersey.
4. Dawkins, R. 1976. The Selfish Gene. Oxford University Press, U.K.
5. Mayr, E. 1982. The Growth of Biological Thought. Diversity, Evolution and Inheritance, Belknap Press of Harvard University Press, Cambridge, Mass.
6. Delcourt, H. R. and P.A. Delcourt. 1991. Quaternary Ecology: A Paleoecological Perspective. Chapman and Hall, London.
7. Raven, P.H., R.F. Evert and S.E. Eichorn. 1992. Biology of Plants (5th ed.). Worth Publishers, New York.
8. Stewart, W. N. and G. R. Rothwell. 1993. Paleobotany and the Evolution of Plants (2nd ed.). Cambridge University Press, Cambridge.
9. Levin, H.L. 1994. The Earth Through Time. 4th ed., updated. Saunders College Publishing; Harcourt Brace College Publishers, Fort Worth.
1. Lavoisier, A.L. 1789. Elements of Chemistry. Translated R. Kerr and reprinted in xii and pp. 1-60. In M.J. Adler (ed.) Great Books of the Western World. 2nd ed., vol 42. Encyclopedia Britannica, Chicago. 1990
2. von Humboldt, Alexander. 1845. Kosmos: Entwurf einer physischen Weltbeschreibung. Translated by E.C. Otté. Reprinted 1997 as Cosmos: A Sketch of the Physical Description of the Universe. Volume I. The Johns Hopkins University Press, Baltimore.
3. Warming, E. 1925. Oecology of Plants: An Introduction to the Study of Plant Communities. (2nd ed.) Oxford University Press, London.
4. Clements, F.E., J.E. Weaver, and H.C. Hanson. 1929. Plant Competition. Carnegie Institution of Washington, Washington, D.C.
5. Tansley, A.G. 1946. Introduction to Plant Ecology. 2nd ed. Allen & Unwin, London.
1. Leopold, A. 1949. A Sand County Almanac. Oxford University Press, London.
2. Carson, R. 1962. Silent Spring. Houghton Mifflin, Boston.
3. Schumacher, E.F. 1973. Small is Beautiful. Blond & Biggs, London.
4. Meadows, D. H., D.L.Meadows, J. Randers, and W.W Behrens III. 1974. The Limits to Growth: A Report for the Club of Rome’s Project on the Predicament of Mankind. 2nd ed. The New American Library, New York.
5. Colinvaux, P. 1978. Why Big Fierce Animals Are Rare: An Ecologist’s Perspective. Princeton University Press, New Jersey.
6. Ehrlich, A. and P. Ehrlich. 1981. Extinction: The Causes and Consequences of the Disappearance of Species. Random House, New York.
7. Botkin, D. B. 1990. Discordant Harmonies: A New Ecology for the Twenty-first Century. Oxford University Press New, York.
8. Wilson, E.O. 1993. The Diversity of Life. W.W. Norton, New York.
9. Noss, R.F. and Cooperrider, A. 1994. Saving Nature’s Legacy: Protecting and Restoring Biodiversity: Defenders of Wildlife and Island Press, Washington, D. C.
10. Diamond, J. 1997. Guns, Germs and Steel. The Fates of Human Societies. W.W. Norton, New York.
1. Williams, C. B. 1964. Patterns in the Balance of Nature. Academic Press, London.
2. Morowitz, H.J. 1968. Energy Flow in Biology: Biological Organization as a Problem in Thermal Physics. Academic Press, New York.
3. Shimwell, D.W. 1971. The Description and Classification of Vegetation. University of Washington Press, Seattle.
4. MacArthur, R. H. 1972. Geographical Ecology: Patterns in the Distribution of Species. Harper & Row, New York.
5. Mueller-Dombois, D. and H. Ellenberg. 1974. Aims and Methods of Vegetation Ecology. Wiley and Sons, New York.
6. Chapman, S.B. 1976. Methods in Plant Ecology. Blackwell, London.
7. Leith, H. and R.H. Whittaker (eds.). 1975. Primary Productivity of the Biosphere. Springer-Verlag, New York.
8. Pielou, E.C. 1977. Mathematical Ecology. Wiley and Sons, New York.
9. Whittaker, R.H. 1975. Communities and Ecosystems. MacMillan, New York.
10. May, R.M. 1976. (ed.) Theoretical Ecology. Principles and Applications. Blackwell, London.
11. Harper, J.L. 1977. The Population Biology of Plants. Academic Press, London.
12. Grime, P. 1979. Plant Strategies and Vegetation Processes. Wiley and Sons, Chichester.
13. Boucher, D. H. 1985. (ed.) The Biology of Mutualism: Ecology and Evolution. Oxford University Press, New York.
14. Pickett, S.T.A. and P.S. White (eds.). 1985. The Ecology of Natural Disturbance and Patch Dynamics. Academic Press, Orlando.
15. Leck, M.A., V.T. Parker and R.L. Simpson (eds). 1989. Ecology of Soil Seed Banks. Academic Press, San Diego.
16. Keddy, P.A. 1989. Competition. Chapman and Hall, London.
17. Aber, J.D. and J. M. Melillo. 1991. Terrestrial Ecosystems. Saunders, Philadelphia.
18. de Groot, R.S. 1992. Functions of Nature. Wolters-Noordhoff, The Netherlands.
19. Archibold, O.W. 1995. Ecology of World Vegetation. Chapman and Hall, London.
Abramsky, A. and M. L. Rosenzweig. 1984. Tilman’s predicted productivity-diversity relationship shown by desert rodents. Nature 309: 150-151.
de Groot, R.S. 1992. Functions of Nature. Wolters-Noordhoff, The Netherlands.
Durant, W. 1944. Caesar and Christ. Simon and Schuster, New York.
Grime, J.P. 2002. Declining plant diversity: empty niches or functional sifts? Journal of Vegetation Science 13:457-460.
Grime, J. P. 1979. Plant Strategies and Vegetation Processes. John Wiley, Chichester.
Huston, M. A. 1997. Hidden treatments in ecological experiments: Re-evaluating the
ecosystem function of biodiversity. Oecologia 110: 449-460.
Hutchinson, G. E. 1959. Homage to Santa Rosalia or Why are there so many kinds of animals? The American Naturalist 93: 145-59.
Keddy, P.A. 2001. Competition. (2nd ed.) Kluwer, Dordrecht, The Netherlands.
Keddy, P.A. 1992. Competition and resources in old fields. Trends in Ecology and Evolution 6: 235-237.
May, R.M. 1988. How many species are there on Earth? Science 241:1441-1449.
Mayr, E. 1982. The Growth of Biological Thought. Diversity, Evolution and Inheritance. Belknap Press of Harvard University Press, Cambridge, MA.
Naeem, S. 2002. Ecosystem consequences of biodiversity loss: the evolution of a paradigm. Ecology 83:1537-1552.
Paglia, C. 1992. Junk bonds and corporate raiders: academe in the hour of the wolf. Pp. 170-248. In Sex, Art and American Culture, Random House, New York.
Perl, J. 2003. Hash of the Titans. The New Republic 228 (3 March): 33-38
Pickett, S.T.A. and P.S. White (eds.). 1985. The Ecology of Natural Disturbance and Patch Dynamics. Academic Press, Orlando.
Pitman, N.C.A. and P.M. Jørgensen, 2002. Estimating the size of the world’s threatened flora. Science 298: 989.
Shipley, B. and R.H. Peters. 1990. A test of the Tilman model of plant strategies: Relative growth rate and biomass partitioning. The American Naturalist 136: 139-153.
Stohlgren, T.J., D.T. Barnett, and J.T. Kartesz. 2003. The rich get richer: patterns of plant invasion in the United States. Frontiers in Ecology and the Environment 1(1):11-14.
Tansley, A. 1951. What is ecology? (pamphlet reprinted in 1987) Biological Journal of the Linnean Society 32:5-16.
von Humboldt, A. 1845. Kosmos: Entwurf einer physischen Weltbeschreibung. Translated by E.C. Otté. Reprinted 1997 as Cosmos: A Sketch of the Physical Description of the Universe. Volume I. The Johns Hopkins University Press, Baltimore, MD.
Wardle, D.A., M.A. Huston, J.P Grime, F. Berendse, E. Garnier, W.K. Laurenroth, H. Setala and S.D. Wilson. 2000. Biodiversity and ecosystem function: an issue in ecology. Bulletin of the Ecological Society of America 81:235-239.