Dansereau, Pierre Mackay

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(b. Outremont, Quebec, Canada, 5 October 1911), biogeography, ecology, environmental studies.

Dansereau pioneered the study of plant ecology in Canada, drawing on both European and North American perspectives. Beginning in the 1930s with studies of phytosociology (the study and classification of plant communities), he progressively broadened his perspective to encompass biogeography, ecological land-use planning, and the urban environment. As both a specialist in plant ecology and a scientist concerned with broader questions of human society and the natural environment, he has urged attention to synthetic perspectives that combine knowledge of nature and of humanity, to be achieved through interdisciplinary environmental studies.

Early Life and Research . Dansereau was born in Outremont, a suburb of Montreal. The Dansereau family was prominent in Quebec society: his grandfather was cofounder and editor of La Presse, Montreal’s largest newspaper, and his father, Lucien Dansereau, was a successful public works engineer. His mother, Marie Archambault, although also French Canadian, was born near Albany, New York. The oldest of five, with a sister and three brothers, his childhood was secure and happy.

Dansereau obtained his early education at the Collège Sainte-Marie, a Jesuit college in Montreal. Its focus on classics gave him little exposure to science. Following the wishes of his parents he began to study law, but after a year his interests turned to farming, and so he enrolled at the Institut Agricole d’Oka, an agricultural college affiliated with the Université de Montréal. There he also studied with Frère Marie-Victorin, founder of the Montreal Botanical Garden and author of La flore laurentienne(1935), who awakened his interest in biology and geography. He would later describe himself as not merely a student, but a disciple of Marie-Victorin. Field trips, particularly to the Gaspé Peninsula in southeast Quebec, sharpened his interest in botany. Upon graduation in 1936, Dansereau began studies at the Université de Genève in Switzerland, where he studied with the ecolo-gist Josiah Braun-Blanquet, receiving a DSc in plant taxonomy in 1939. From Braun-Blanquet he gained a grounding in the Zürich-Montpellier school of phytosociology, including its distinctive approach to identifying and classifying plant communities, and understanding their dynamics, on the basis of species composition. On his return to Quebec he would contribute to introducing North American ecologists to this perspective.

In 1935 Dansereau married Françoise Masson; they have enjoyed a long and happy marriage, Françoise accompanying Pierre on scientific travels while pursuing her own political and social concerns. They have had no children. In the early 1930s Dansereau exhibited his interest in political and social issues as coleader of Jeune-Canada, a group of university students urging that Quebec assert more firmly its autonomy and French identity. The organization was active for several years but by the late 1930s had dispersed.

Between 1940 and 1950 Dansereau taught at the Université de Montréal while serving as botanist, and subsequently assistant director, at the Montreal Botanical Garden. In addition, between 1943 and 1949 he was director of the provincial biogeography service. During this decade, a significant focus of his research was the application of phytosociological methods to vegetation in Quebec, particularly maple forests. But he soon broadened his research beyond his European training. With a few other geographically oriented ecologists, he experimented with describing and classifying vegetation in terms of structure, presenting graphically the distinctive forms, or physiognomy, of the principal vegetation types. This approach would, he suggested, be more biologically meaningful than descriptions based on plant taxa.

This work epitomized Dansereau’s growing interest in applying a geographical perspective to plant communities by understanding, through comparison, how their characteristic forms were related to the geology and climate of regions. In linking ecology with biogeography, he drew from the French geographer Emmanuel de Martonne and his classic text, Traité de Géographie Physique (1905). Dansereau also expressed this geographical orientation by pursuing research in a variety of environments. In 1945 he traveled to Brazil to teach and conduct research. He would maintain a lifelong affinity for that country. In 1950 he studied Arctic plant communities on Baffin Island in the Arctic Ocean. In the course of his career he would conduct research across North and South America, as well as in Australia, New Zealand, the Philippines, and the Canary Islands; he has also lectured on every continent except Antarctica.

Although the 1940s were productive for Dansereau in terms of research, his position at the Université de Montréal was not secure. He had introduced ecology to what was at the time a fairly conservative institution, and the status of the discipline remained, at best, provisional. Frustrated, Dansereau moved in 1950 to the University of Michigan. His five years there as professor of botany proved among the most satisfying and stimulating of his career. (He also during this time taught for short periods at Stanford University and the University of Vermont). In his research he pursued a variety of avenues, including work on forest dynamics and vegetation change. He explored other areas as well: the taxonomy and phenomenology of vegetation and aspects of the relation between ecology and evolution, including the ecology of natural selection.

In a series of publications, particularly his synthesis of the ecological and biogeographical sciences titled Biogeography: An Ecological Perspective (1957), Dansereau displayed his interest in the common ground of disciplines concerned with the environment and the potential for collaboration. This theme, already evident in his work on representation and classification of vegetation structure, would become increasingly evident in his writings, particularly as environmental concerns began to reshape the intellectual and public context of ecology. Nevertheless, while seeking synthesis over specialization, he continued to insist on the need to ground one’s work in a specific discipline.

In 1955 Dansereau returned to the Université de Montréal, serving until 1961 as director of its Botanical Institute and dean of the Faculty of Sciences. Again, however, he found the intellectual environment less open than he had hoped, and not just in scientific terms. Meanwhile, his American sojourn had not diminished his commitment to Quebec political and social concerns, and in 1956 Dansereau became president of Le Rassemblement, a movement for democratization and social justice. (The vice president was Pierre Trudeau, who would go on to serve as prime minister of Canada between 1968 and 1984). In response, Maurice Duplessis, the authoritarian premier of Quebec, insisted that the university strip Dansereau of his deanship. Dansereau kept his deanship, but the university accommodated Duplessis by urging Dansereau to stick to his science.

Ecology and Urban Society . In 1961 Dansereau returned to the United States to teach at Columbia University and serve as assistant director of the New York Botanical Garden. Life in the metropolis opened up new perspectives and opportunities. Captivated by the complexities of the urban ecosystem, he explored the application of ecological concepts to cities, insisting that, as an ecologist, he found cities as interesting as “natural” communities.

Dansereau also pursued his interest in interdisciplinary environmental studies, seeking to define a common ground shared by ecological and social perspectives. In his view, solutions to environmental challenges demanded not just science, but attention to culture and psychology; for Dansereau, this implied a need for dialogue between scientists and individuals in government, business, and civil society. In 1968 he organized a wide-ranging symposium on the urban environment, published in 1970 as Challenge for Survival. He also urged formation of an interdisciplinary environmental science, in which specialists in the Earth and biological sciences would collaborate with experts in agriculture, economics, and other fields. Anticipating the advent of university environmental studies programs and departments, this approach, he argued, would entail reorganization of academic structures and curricula.

During the 1960s an increasingly humanistic perspective became evident in Dansereau’s work. He engaged in wide-ranging reflections on such topics as the relations between the scientific and other cultures and the social responsibilities of scientists. This was not entirely novel for Dansereau: he had exhibited since the 1930s a concern for social and ethical issues. In the 1960s he extended this concern, combining ecological ideas with those of a variety of writers and public intellectuals of the time, including Jean Gottman, Kenneth Boulding, and particularly Lewis Mumford, whose humanistic sensibility toward society and technology he admired.

Dansereau was, of course, not alone among North American ecologists in responding to the novel political prominence of their discipline by exploring its wider implications. But the depth and seriousness with which he drew from humanistic as well as scientific perspectives was more unusual. This, he felt, was consistent with his critical perspective on scientific conventions, especially the notion that objectivity demanded depersonalization of scientific expression. In Dansereau’s view, that notion denied the essential social identity of scientists while separating their work from other forms of learning. As he often affirmed, authentic knowledge could be derived as much from artistic as from scientific sources—indeed, Dansereau felt, the search for such knowledge demanded attention to all of one’s faculties and senses, a perspective he would characterize as acting as a “barefoot scientist.”

For Dansereau, the French philosopher Pierre Teil-hard de Chardin served as a model of this reconciliation of scientific and other forms of knowledge and perception. He had first encountered Teilhard’s ideas in the 1930s, through Marie-Victorin. He subsequently maintained an active interest, writing several essays and conference presentations on Teilhard’s ideas and serving in the late 1960s as president of the American Teilhard de Chardin Association. While he did not follow Teilhard in all the details of his arguments regarding the convergence of evolution and religion, he admired his effort to reconcile the scientific and the spiritual.

Ecology in Montreal . In 1968 Dansereau returned to the Université de Montréal as professor of ecology and director of the Centre de recherches écologiques de Montreal. Four years later, he moved across town to the Université du Quebec à Montréal as program director of the Centre de recherché en sciences de l’environnement.

In Montreal he initiated a variety of efforts to apply his ideas regarding the reconciliation of ecology and human society. In the early 1970s he led a large study of the terrain set aside for the proposed Mirabel Airport, north of Montreal. A vast area of land had been expropriated, far more than that required for the airport itself, and Dansereau saw an opportunity to reconstitute its use on an ecological basis. Accordingly, he assembled an interdisciplinary group of specialists who examined the region’s natural and social environment and integrated the results with the area’s economic potential and the cultural factors shaping its use. The study, known as the EZAIM project (Écologie de la zone de l’aéroport international de Montréal), was, Dansereau believed, a successful experiment in integrating ecological considerations into land-use decisions.

In 1971 Dansereau proposed a new model of the ecosystem: the boule-de-flèches (ball of arrows). An elaboration of conventional trophic models, it incorporated in six trophic levels both natural and human factors; in particular, the two top levels—investment and control— incorporated the influence of psychological functions such as will and agency. In effect, the model sought to encompass the ecological significance of deliberate action and thus, Dansereau argued, could be applied as readily to an ecosystem dominated by humans, such as a city, as to more “natural” ecosystems. This was not a predictive or quantitative model; rather, it served to exhibit how, in ecological contexts, humans were unique—their resource use determined not just by need, but by social and cultural factors—but that this uniqueness could nevertheless be incorporated within an understanding of ecosystems. It was in this sense consistent with the interest then emerging among some ecologists in finding ways to incorporate human use of the environment within ecology, as exemplified, for example, by UNESCO’s Man and the Biosphere Program.

Dansereau also became involved in other activities relating to science and the human environment. In 1968 he was named to the Science Council of Canada; he was also appointed vice president of a federal commission on housing and urban development. This work provided additional avenues through which he expressed his view that human-dominated ecosystems could be attractive and productive habitats. This perspective was itself founded on a lifelong optimism, an outlook that was the product of a happy childhood but also, he has stressed, grounded on science and on the history of humans learning to live with and adapt to nature. This optimism, however, had to be founded on accepting responsibility for alleviating social and economic injustices and for reducing one’s own consumption through an embrace of “joyous austerity.”

In 1976 Dansereau was named professor emeritus at the Université du Quebec à Montréal; at age ninety-five in 2006, he continued to write and participate in public affairs. He has received many honors: a member of the Royal Society of Canada since 1949, he was named a Companion of the Order of Canada in 1969, and a grand officer of the Order of Québec in 1992. In November 2001 Dansereau was inducted into the Canadian Science and Engineering Hall of Fame. He has also received fifteen honorary degrees.


A large collection of unpublished materials relating to the life and work of Dansereau are held at the archives of the Université du Québec à Montréal. A bibliography of Dansereau’s works is available at the Web site of the Union for Sustainable Development, http://www.udd.org/Anglais/lefonds.html.


“Description and Recording of Vegetation upon a Structural Basis.” Ecology 32 (1951): 172–229.

Biogeography: An Ecological Perspective. New York: Ronald Press, 1957.

“Ecological Impact and Human Ecology.” In Future Environments of North America, edited by F. Fraser Darling and John P. Milton. Garden City, NY: Natural History Press, 1966.

Challenge for Survival: Land, Air, and Water for Man in Megalopolis. New York: Columbia University Press, 1970.

Inscape and Landscape. Toronto: Canadian Broadcasting Corporation, 1973.

La lancée, 1911–1936. Sainte-Foy, Quebec: Éditions Multimondes, 2005. First volume of a planned three-volume autobiography.


L’archives de Radio-Canada. Dansereau, lécologiste aux pieds nus. Available from http://archives.radio-canada.ca/IDD-0-16-639/sciences_technologies/pierre_dansereau Extensive audiovisual archive of Dansereau’s life and work (in French).

Dumesnil, Thérèse. Pierre Dansereau, l’écologiste aux pieds nus. Montreal: Éditions Nouvelle Optique, 1981.

National Film Board of Canada. An Ecology of Hope. 2001. A documentary film about Dansereau’s life and work.

Vaillancourt, Jean-Guy. “Pierre Dansereau, écologue, écosociologue, et écologiste.” Sociologie et sociétés 31 (1999): 191–193.

Stephen Bocking