Christen Christensen Raunkiær (29 March 1860 – 11 March 1938) was a Danish

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

, who was a pioneer of

plant ecology Plant ecology is a subdiscipline of ecology that studies the distribution and abundance (ecology), abundance of plants, the effects of environmental factors upon the abundance of plants, and the interactions among plants and between plants and ...

. He is mainly remembered for his scheme of plant strategies to survive an unfavourable season ("life forms") and his demonstration that the relative abundance of strategies in floras largely corresponded to the Earth's climatic zones. This scheme, the Raunkiær system, is still widely used today and may be seen as a precursor of modern plant strategy schemes, e.g. J. Philip Grime's CSR system.

Life

He was born on a small heathland farm, named Raunkiær, in Lyhne parish in western

Jutland Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...

Denmark Denmark is a Nordic countries, Nordic country in Northern Europe. It is the metropole and most populous constituent of the Kingdom of Denmark,, . also known as the Danish Realm, a constitutionally unitary state that includes the Autonomous a ...

. He later took his surname after it. He succeeded Eugen Warming as professor in botany at the

University of Copenhagen The University of Copenhagen (, KU) is a public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, after Uppsala University. ...

and the director of the Copenhagen Botanical Garden, a position he held from 1912 to 1923. He was married to the author and artist Ingeborg Raunkiær (1863–1921), who accompanied him on journeys to the West Indies and the Mediterranean and made line drawings for his botanical works. They divorced in 1915, the same year as their only son Barclay Raunkiær died. Raunkiær later married the botanist Agnete Seidelin (1874–1956). Raunkiær's research axiom was that everything countable in nature should be subjected to numerical analysis, e.g. the number of male and female catkins in monecious plants and the number of male and female individuals in

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

plants. Raunkiær also was an early student of

apomixis In botany, apomixis is asexual development of seed or embryo without fertilization. However, other definitions include replacement of the seed by a plantlet or replacement of the flower by bulbils. Apomictically produced offspring are geneti ...

in flowering plants and

hybrid swarm A hybrid swarm is a population of hybrids that has survived beyond the initial hybrid generation, with interbreeding between hybrid individuals and backcrossing with its parent types. Such population are highly variable, with the genetic and ...

s. In addition, he studied the effect of

soil pH Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the neg ...

on plants and plants on soil pH, a work his apprentice Carsten Olsen continued. After his retirement, C. Raunkiær made numerical studies of plants and flora in the literature ("The flora and the heathland poets", "The dandelion in Danish poetry", "Plants in the psalms"). In these studies, he applied strict quantitative criteria, like in his ecological studies. For example, he defined a poet as a person who has written 1,000 or more lines of verse.

Legacy

Life form spectra

Raunkiær devised a system for categorising plants by life-form as a way of ecologically meaningful comparison of species and vegetation in regions having different

flora Flora (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

s. Raunkiær compared statistically local life form spectra (relative abundance) with the world average, which he called "the normal spectrum" (Raunkiær 1918 – see below). Thereby, he devised the first null model in the history of ecology. Raunkiær was a keen naturalist, who described the

and

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

, the

Virgin Islands The Virgin Islands () are an archipelago between the Atlantic Ocean, North Atlantic Ocean and northeastern Caribbean Sea, geographically forming part of the Leeward Islands of the Lesser Antilles in the Caribbean, Caribbean islands or West Indie ...

Tunisia Tunisia, officially the Republic of Tunisia, is a country in the Maghreb region of North Africa. It is bordered by Algeria to the west and southwest, Libya to the southeast, and the Mediterranean Sea to the north and east. Tunisia also shares m ...

, and other countries. In contrast to many contemporary naturalist, however, he strongly promoted quantitative and numerical approaches and experimentation. He devised a method to quantify the abundance of plants in vegetation as frequency in subplots and used it for quantitative studies of a range of plant communities.

Raunkiær's law

When plotting the number of species in a plant community that fell in each 20-percentile frequency class from very frequent, i.e. numerically dominant, to very infrequent, Raunkiær discovered that most species were either very common or very rare. This came to be known as "Raunkiær's law" and is related to R. A. Fisher's logseries distribution and to Frank W. Preston's lognormal distribution of the number of individuals of each species in a community. The significance of his idea was, however, disputed already by some of his contemporaries.

Leaf size in plant geography

As a further experiment in characterizing plant communities, Raunkiaer devised a numerical scheme based on leaf size classes and leaf type (simple or compound) that was extended by L. J. Webb and is used as a way to classify forest types more simply than by lists of component species.

Popular references

Farley Mowat, in his book, Never Cry Wolf, described using a Raunkiær's Circle in making a "cover degree" study to determine the ratios of various plants one to the other. He spoke of it as "a device designed in hell."

Scientific publications

* Raunkiær, C. (1887) Botanisk Tidsskrift 16, 152–167. * Raunkiær, C. (1888–89) Botanisk Tidsskrift 17, 20-105 Description in English of some new and of some unsatisfactorily known species of Myxomycetes described in the preceding treatise. Botanisk Tidsskrift 17, 106–110. * Raunkiær, C. (1889) Notes on the vegetation of the North-Frisian Islands and a contribution to an eventual flora of these islands. Botanisk Tidsskrift 17, 179–196. * Raunkiær, C. (1893) Botanisk Tidsskrift 18, 19–23. * Raunkiær, C. (1895) l. Enkimbladede. Gyldendalske Boghandels Forlag, København. * Raunkiær, C. (1901) Botanisk Tidsskrift 24, 223–238. * Raunkiær, C. (1902) Botanisk Tidsskrift 24, 289–296. * Raunkiær, C. (1903) Anatomical Potamogeton-Studies and Potamogeton fluitans. Botanisk Tidsskrift 25, 253–280. * Ostenfeld, C.H. & Raunkiær, C. (1903) nglish summary Botanisk Tidsskrift 25, 409–413. * Raunkiær, C. (1904) Oversigt over Det Kongelige Danske Videnskabernes Selskabs Forhandlinger, 1904, 330–349. * Raunkiær, C. (1904) Botanisk Tidsskrift 26, XIV. THIS PAGE DOES NOT CONTAIN A PAPER BY RAUNKIAER WITH THAT TITLE NOR DOES THE ENTIRE VOLUME. Ch. 1 in Raunkiær (1934): Biological types with reference to the adaption of plants to survive the unfavourable season, p. 1. * Raunkiær, C. (1905) Oversigt over Det Kongelige Danske Videnskabernes Selskabs Forhandlinger, 1905, 347–438.THIS PAGE RANGE SEEMS DOUBTFUL, BUT IS REPEATED ON UMPTEEN ONLINE PAGES. * Raunkiær, C. (1905) Botanisk Tidsskrift 26, 86–88. * Raunkiær, C. (1906) Botanisk Tidsskrift 27, 313–316. * Raunkiær, C. (1906) Oversigt over Det Kongelige Danske Videnskabernes Selskabs Forhandlinger, 1906, 31–39. * Raunkiær, C. (1907) 132 pp. Ch. 2 in Raunkiær (1934): The life-forms of plants and their bearings on geography, p. 2-104. * Raunkiær, C. (1907) Botanisk Tidsskrift 28, 210. Ch. 3 in Raunkiær (1934): The life-form of Tussilago farfarus, p. 105-110. * Raunkiær, C. (1908) Botanisk Tidsskrift 29, 42–43. German translation: Beiheft zum Bot. Centralbl., 27 (2), 171-206 (1910). Ch. 4 in Raunkiær (1924): The statistics of life-forms as a basis for biological plant geography, p. 111-147. * Raunkiær, C. (1908)

Fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

from the Danish West Indies collected 1905–1906. Botanisk Tidsskrift 29, 1–3. * Raunkiær, C. (1909) Kongelige Danske Videnskabernes Selskabs Skrifter - Naturvidenskabelig og Mathematisk Afdeling, 7.Rk., 8, 1-70. Ch. 5 in Raunkiær (1934): The life-forms of plants on new soil, p. 148-200. * Raunkiær, C. (1909a) Botanisk Tidsskrift 30, 20–132. Ch. 6 in Raunkiær (1934): Investigations and statistics of plant formations, p. 201-282. * Raunkiær, C. (1911) In: Biologiske Arbejder tilegnede Eug. Warming paa hans 70 Aars Fødselsdag den 3. Nov. 1911. Kjøbenhavn. Ch. 7 in Raunkiær (1934): The Arctic and Antarctic chamaephyte climate, p. 283-302. * Raunkiær, C. (1912) Measuring-apparatus for statistical investigations of plant-formations. Botanisk Tidsskrift 33, 45–48. * Raunkiær, C. (1913) Botanisk Tidsskrift 33, 197–243. Ch. 8 in Raunkiær (1934): Statistical investigations of the plant formations of Skagens Odde (The Skaw), p. 303-342. * Raunkiær, C. (1914) Mindeskrift i Anledning af Hundredeaaret for Japetus Steenstrups Fødsel (eds H. F. E. Jungersen & E. Warming), pp. 1–33. København. Ch. 9 in Raunkiær (1934): On the vegetation of the French mediterranean alluvia, p. 343-367. * Raunkiær, C. (1916) Botanisk Tidsskrift 34, 1–13. Ch. 10 in Raunkiær (1934): The use of leaf size in biological plant geography, p. 368-378 * Raunkiær, C. (1916) Botanisk Tidsskrift 34, 289–311. * Raunkiær, C. (1918) nglish summary On leaftime in the descendants from

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

es with different leaftimes]. Botanisk Tidsskrift 36, 197–203. * Raunkiær, C. (1918) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 1 (3), 1-80. Ch 11 in Raunkiær (1934): Statistical researches on plant formations, p. 379-424. * Raunkiær, C. (1918) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 1 (4), 1–17. Ch. 12 in Raunkiær (1934): On the biological normal spectrum, p. 425-434. * Raunkiær, C. (1918) . Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 1 (7), 1–17. * Frederik Børgesen, Børgesen, F. & Raunkiær, C. (1918
Mosses and Lichens collected in the former Danish West Indies
Dansk Botanisk Arkiv 2 (9): 1–18. * Raunkiær, C. (1919) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 1 (12), 1-22. * Raunkiær, C. (1920) En naturhistorisk Studie. Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 2 (4), 1-90. * Raunkiær, C. (1920) Botanisk Tidsskrift 37, 151–158. Ch. 13 in Raunkiær (1934): On the significance of Cryptogams for characterizing Plant climates, p. 435-442. * Raunkiær, C. (1922) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 3 (10), 1-74. Ch. 14 in Raunkiær (1934): The different influence exercised by various types of vegetation on the degree of acidity (Hydrogen-ion concentration), p. 443-487. * Raunkiær, C. (1926) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 5 (5), 1-47. Ch. 15 in Raunkiær (1934): The Nitrate content of

Anemone nemorosa ''Anemonoides nemorosa'' (syn. ''Anemone nemorosa''), the wood anemone, is an early-spring flowering plant in the buttercup family Ranunculaceae, native to Europe. Other common names include windflower, European thimbleweed, and smell fox, an all ...

growing in various localities, p. 488-516. * Raunkiær, C. (1926) (Isoreagent-Studier II). Botanisk Tidsskrift 39, 329–347. * Raunkiær, C. (1926) Botanisk Tidsskrift 39, 348–356. * Raunkiær, C. (1928) Biologiske Meddelelser / Kongelige Danske Videnskabernes Selskab, 7 (1), 1-47. Ch 16 in Raunkiær (1934): The area of dominance, species density, and formation dominants, p. 517-546. * Raunkiær, C. (1928) Myxomycetes from the West Indian Islands St. Croix, St. Thomas and St. Jan. Dansk Botanisk Arkiv 5 (16), 1–9. * Raunkiær, C. (1930) Botanisk Tidsskrift 41, 257–258. * Raunkiær, C. (1934) Botaniske Studier, 1. haefte (ed C. Raunkiær), pp. 3–30. J.H. Schultz Forlag, København. * Raunkiær, C. (1934) The Life Forms of Plants and Statistical Plant Geography. Introduction by A.G. Tansley. Oxford University Press, Oxford. 632 pp. Collection of 16 of Raunkiær's publications plus one new. * Raunkiær, C. (1934) Botanical studies in the Mediterranean region. Ch. 17 in The Life Forms of Plants and Statistical Plant Geography, pp. 547–620. * Raunkiær, C. (1935) The vegetation of the sand dunes north of

Sousse Sousse, Sūsah , or Soussa (, ), is a city in Tunisia, capital of the Sousse Governorate. Located south of the capital Tunis, the city has 271,428 inhabitants (2014). Sousse is in the central-east of the country, on the Gulf of Hammamet, which ...

. Botaniske Studier, 3. haefte (ed C. Raunkiær), pp. 244–248. J.H. Schultz Forlag, København. * Raunkiær, C. (1936) The life-form spectrum of some Atlantic islands. Botaniske Studier, 4. haefte (ed C. Raunkiær), pp. 249–328. J.H. Schultz Forlag, København. * Raunkiær, C. (1937) Botaniske Studier, 5. haefte (ed C. Raunkiær), pp. 357–382. J.H. Schultz Forlag, København. * Raunkiær, C. (1937) Botaniske Studier, 5. haefte (ed C. Raunkiær), pp. 329–336. J.H. Schultz Forlag, København. * Raunkiær, C. (1937) Life-form, genus area, and number of species. Botaniske Studier, 5. haefte (ed C. Raunkiær), pp. 343–356. J.H. Schultz Forlag, København. * Raunkiær, C. (1937) Botaniske Studier, 5. haefte (ed C. Raunkiær), pp. 337–342. J.H. Schultz Forlag, København.

Reviews and biographies

* *
Biography by O.G. Petersen in: Dansk Biografisk Lexikon, 1st edn 1887-1905 (ed. Carl Frederik Bricka)
* Biography by Carl Christensen in: Dansk Biografisk Leksikon, 3rd edn 1979-1984 (ed. Svend Cedergreen Bech).

References

External links

*http://www.wku.edu/%7Esmithch/chronob/RAUN1860.htm {{DEFAULTSORT:Raunkiaer, Christen C. 20th-century Danish botanists Danish ecologists Danish science writers Academic staff of the University of Copenhagen University of Copenhagen alumni 1860 births 1938 deaths Plant life-forms 19th-century Danish botanists