WHAT IS PLANT GEOGRAPHY?

Lecture Schedule

Lecture

" . . . that grand subject, that almost keystone of the laws of creation, Geographical Distribution."  [Charles Darwin, 1845, in a letter to Joseph Dalton Hooker, the Director of the Royal Botanic Garden, Kew]

Reading: Text. Chapter 1: The Science of Biogeography [pp. 3-12]

I. What is Biogeography?
  florisitics / faunistics
  ecology
  history

Summary definition:

"Biogeography is the study of distributions of organisms, both past and present. It is the science that attempts to describe and understand the innumerable patterns in the distribution of species and larger taxonomic groups." [Brown & Gibson, 1983]

II. Approaches to Biogeography

   1. Florisitic (or faunisitic) Biogeography

Floristic (plants) or faunistic (animals) biogeography simply asks where various taxa are distributed.

   2. Ecological Biogeography

Generally not taxonomically based- i.e., it asks questions about the distributions of attributes of organisms without being concerned with the specific classification of the plants and animals involved.

   3. Historical Biogeography

Historical biogeography combines taxonomy (phylogenetics) with knowledge of both present and past climates and geography in trying to explain how plants and animals have attained their current distributions.


III. History of Plant Geography (Reference: Szafer, 1975)

   1. Theophrastus, the disciple of Aristotle (2nd century B.C.)

He included a separate chapter (IV) in his work "Studies on Plants" devoted to the geographical distribution of plants. Even though confined to the Mediterranean region, he is the first to set biogeography separate from other branches of plant sciences, and considered the Father of Geography. Theophrastus had no followers, either in ancient times nor in the Middle Ages.

   2. Tournefort (1717)

Provided a fairly exact description of the vertical zones of the vegetation of Mt. Ararat.

   3. Linnaean period (mid 1700s)
      i. Ch. Linnaeus: described vegetation of the Scandinavian Peninsula
      ii. A. von Haller: described vegetation of Switzerland
      iii. J.L.G. Soulavie: described vegetation of southern France
      iv. Comte de Buffon: Buffon's law (the 1st principle of biogeography)

   4. Alexander von Humboldt (1769-1859)

Father of modern plant geography. Published in 1817 "Die Distributione Geographica Plantarum etc." in which he presented for the first time the distribution of plants over the Earth, as governed by climate. More on him later.

   5. A.P. De Candolle (1778-1841)

Published in 1809 "Agricultural and Botanical Geography" with emphasis on the origin and history of many cultivated species.

   6. J. F. Schouw (1789-1852) [Danish]

Published in 1822 the first comprehensive textbook on plant geography, in Danish and German.

   7. A De Candolle

Published in 1856 a two volume book on plant geography. Joseph D. Hooker reviewed the book with great excitement as it supported the then emerging ideas of evolution.

   8. Charles Darwin and Alfred Wallace

Publication of "Origin of Species" in 1859, based in part on Wallace's biogeographical knowledge, paid special attention to biogeographical phenomena, thus giving permanence and significance to animal and plant geography.

   9. Joseph Hooker (Europe) and Asa Gray (United States)

The two plant systematists who assisted Darwin and then surged ahead with plant geography.

   10. The 20th Century has then seen an explosion of modern biogeography as we will see and includes the following botanists (in alphabetical order):

Dan Axelrod, Herbert Baker, Lucy Braun, Stanley Cain, Sherwin Carlquist, Jorge Crisci, Leon Croizat, Margaret Davis, Jim Doyle, F. Fosberg, Vicky Funk, Al Gentry, Henry Gleason, Eric Hultén , Hugh Iltis, Arthur Kruckeberg, H. Li, Robert MacArthur, M. McKenna, Hal Mooney, E. Pielou, D. Porter, C. Raunkiaer, Peter Raven, Ledyard Stebbins, Arman Takhtajan, Robert Thorne, J. Wolfe