zonationhttp://www.oed.com/dictionary/zonation_n%3Ftab%3Dmeaning_and_usezonation, n.
First published 1921; not fully revised

zonationnoun

    1. a.
      1898–
      Distribution in zones or regions of definite character; spec. in Ecology, the distribution of plants into specific zones which are characterized by their dominant species.
      1. 1898
        The zonal constitution and disposition of plant formations. By Frederic E. Clements.
        Rep. 67th Meeting Brit. Assoc. Advancem. Sci. 1897 863 (heading)
      2. 1898
        The author has here reviewed the phytogeographical contributions bearing upon the subject in hand, with especial reference to the part they have played in the elaboration of the conception of zonation. In addition, he has endeavoured to demonstrate the fundamental universality of zonation in all divisions of the floral covering.
        Rep. 67th Meeting Brit. Assoc. Advancem. Sci. 1897 863
      3. 1904
        Zonation in a habitat... The line that connects the points of accumulated or abrupt change in the symmetry is a stress line or ecotone... Ecotones are well marked between formations, particularly where the medium changes: they are less distinct within formations. It is obvious that an ecotone separates two different series of zones in the one case, and merely two distinct zones in the other.
        F. E. Clements in Bot. Surv. Nebraska No. 7. 153
      4. 1926
        Adjacent plant communities are often arranged in more or less definite zones, following one another in constant order. This is specially noticeable in ascending a mountain (where it is called altitudinal zonation).
        A. G. Tansley & T. F. Chipp, Aims & Methods in Study of Vegetation iv. 53
      5. 1936
        Reliable local zonation of both the Eocene and the Oligocene has been worked out in the Tampico area.
        J. Muir, Geol. Tampico Region, Mexico 121
      6. 1969
        Marine work during the first eight months concentrated on community structure and zonation on cliffs, reef flats and in mangrove woodland.
        Nature 15 March 1005/2
      7. 1971
        It is first necessary therefore to establish a regional metamorphic zonation.
        Scottish Journal of Geology vol. 7 306
      8. 1981
        I would have preferred to have seen an accompanying annotated sketch so that the plant zonations could be easily recognised.
        Birds Autumn 63/3
    2. b.
      1899–
      Formation of zones in the oocytes of certain plants and animals.
      1. 1899
        There is a stage called zonation in which the nuclei, usually in metaphase, are lined up around the ooplasm.
        Botanical Gazette vol. 28 237
      2. 1902
        During the completion of the mitosis the ooplasm and periplasm become clearly differentiated, but as yet no plasmoderma exists. This process of differentiation has been termed zonation.
        Botanical Gazette December 421
      3. 1975
        The zonation of the ooplasm reveals that a majority of the oocytes [of the teleost Schizothorax richardsonii] have a darkly stained inner and a lightly stained outer zone.
        Acta Anatomy vol. XCIII. 512

zonation, n. was first published in 1921; not fully revised.

zonation, n. was last modified in July 2023.