Frederic Clements

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Frederic Edward Clements
Born(1874-09-16)September 16, 1874
Lincoln, Nebraska, United States
DiedJuly 26, 1945(1945-07-26) (aged 70)
Alma materUniversity of Nebraska
Known forEcological succession
Spouse(s)Edith Gertrude Schwartz
Scientific career
FieldsPlant ecology

Frederic Edward Clements (September 16, 1874 – July 26, 1945) was an American plant ecologist and pioneer in the study of vegetation succession.[2]:51


Born in Lincoln, Nebraska, he studied botany at the University of Nebraska, graduating in 1894 and obtaining a doctorate in 1898. (One of his teachers was botanist Charles Bessey, and he was a classmate of Willa Cather and Roscoe Pound.) While at the University of Nebraska, he met Edith Gertrude Schwartz (1874–1971), also a botanist and ecologist, and they were married in 1899.[1][3]

In 1905 he was appointed full professor at the University of Nebraska, but left in 1907 to head the botany department at the University of Minnesota in Minneapolis. From 1917 to 1941 he was employed as an ecologist at the Carnegie Institution of Washington in Washington, D.C., where he was able to carry out dedicated ecological research.[1]

During winter he worked at research stations in Tucson, Arizona and Santa Barbara, California, while in the summer he performed fieldwork at the Carnegie Institution's Alpine Laboratory, a research station in Angel Canyon on the slopes of Pikes Peak, Colorado. During this time he worked alongside staff of the U.S. Soil Conservation Service. In addition to his field investigations, he carried out experimental work in the laboratory and greenhouse, both at the Pikes Peak station and at Santa Barbara.[1]

Theory of vegetation change to climax community[edit]

From his observations of the vegetation of Nebraska and the western United States, Clements developed one of the most influential theories of vegetation development. Vegetation composition does not represent a permanent condition but gradually changes with time. Clements suggested that the development of vegetation can be understood as a unidirectional sequence of stages resembling the development of an individual organism. After a complete or partial disturbance, vegetation grows back (under ideal conditions) towards a stable" climax state," which describes the vegetation best suited to the local conditions. Though any actual instance of vegetation might follow the ideal sequence towards stability, it can be interpreted in relation to that sequence, as a deviation from it due to non-ideal conditions.

In these studies, he and R. Pound developed the widely-used method of sampling using quadrats around 1898.[4][5][6]

Clements's climax theory of vegetation dominated plant ecology during the first decades of the twentieth century, though it was criticized significantly by ecologists Henry Gleason and Arthur Tansley early on, and by Robert Whittaker mid-century, and largely fell out of favor. However, significant Clementsian trends in ecology re-emerged towards the end of the twentieth century.

Community-unit view of vegetation types or plant communities[edit]

In his 1916 publication, Plant Succession, and his 1920 Plant Indicators, Clements metaphorically equated units of vegetation, (now called vegetation types or plant communities) with individual organisms.[7] His observations were that some groups of species were repeatedly associated together (Association (ecology)).[7] He believed that some species were dependent on the group, and the group on that species (obligatory relationship), metaphorically as organs and the animal containing them depend on each other.[7] He observed little overlap in kinds of species from type to type, with many species confined to just a single type.[7] Some plants were widespread over vegetation types, but the areas of geographical overlap (ecotones) was narrow.[7] His view of a community as a distinct unit was challenged in 1926 by Henry Gleason, who viewed vegetation as a continuum, not a unit, with associations being merely coincidental, and that any support by observations or data of clusters of species as predicted by Clements' view was either an artifact of the observer's perception or a result of defective data analysis.[7][8]


Clements was an advocate of neo-Lamarckian evolution. Ecologist Arthur Tansley wrote that because of his support for Lamarckism, Clements "never seemed to give proper weight to the results of modern genetical research."[9]

Science historian Ronald C. Tobey has commented that:

[Clements] believed that plants and animals could acquire a wide variety and range of characteristics in their struggle to survive and adapt to their environment, and that these features were heritable. In the 1920s, he conducted experiments to transform plant species native to one ecological zone into a species adapted to another, higher, zone. Clements was quite convinced of the validity of his experiments, but this experimental Lamarckism fell to experimental disproof in the 1930s.[10]

Clements spent much time trying to demonstrate the inheritance of acquired traits in plants. By the late 1930s scientists had provided Darwinian explanations for the results of his transplant experiments.[11]


In 1903, the flower Clementsia rhodantha ("Clements' rose flower"), a stonecrop, was named in honor of Frederic Clements.[12]


Among his works are:

See also[edit]


  1. ^ a b c d "Frederic E. Clements". University of California at Santa Barbara. Retrieved June 28, 2015.
  2. ^ Humphrey, Harry Baker (1961). Makers of North American Botany. Ronald Press. ISBN 9780826045201. LCCN 61-18435.
  3. ^ Clements, Edith S (1960). Adventures in Ecology. Hafner Publishing Company. ISBN 9780028429304.
  4. ^ Pound, R.; Clements, F. E. (June 1898). "A method of determining the abundance of secondary species". Minnesota Botanical Studies. 2: 19–24.
  5. ^ Pound, R.; Clements, F. E. (1900). Phytogeography of Nebraska (Second ed.). pp. 61–63.
  6. ^ Weaver, J. E. (November 1919). "The Quadrat Method in Teaching Ecology". The Plant World. 21 (11): 267–283. JSTOR 43477708.
  7. ^ a b c d e f Sawyer, John O.; Keeler-Wolf, Todd (1995). A Manual of California Vegetation. California Native Plant Society. ISBN 9780943460260.
  8. ^ Tobey, Ronald C (1981). Saving the Prairies: The Life Cycle of the Founding School of American Plant Ecology, 1895-1955. University of California. ISBN 9780520043527.
  9. ^ Tansley, A. G. (1947). Obituary Notice: Frederic Edward Clements, 1874--1945. Journal of Ecology 34 (1): 194-196.
  10. ^ Tobey, Ronald C. (1981). Saving the Prairie: The Life Cycle of the Founding School of American Plant Ecology, 1895-1955. University of Chicago Press. p. 182. ISBN 0-520-04352-9
  11. ^ Hagen, Joel B. (1993). Clementsian Ecologists: The Internal Dynamics of a Research School. Osiris. Vol. 8, Research Schools: Historical Reappraisals. pp. 178-195.
  12. ^ Britton, N L; Rose, J N (1903). "Botanical contributions: New or noteworthy North American Crassulaceae". Bulletin of the New York Botanical Garden. 3: 3.
  13. ^ IPNI.  Clem.