Abstract
DR. CLEMENTS'S enthusiastic and prolific researches in pure ecology are well known to botanists. In his latest publication he endeavours to apply his principles and methods to the practical problems of agriculture, stock-raising, and forestry, with special reference to the Western United States. According to his view, every plant is an indicator of “conditions, processes, or uses,” because it is the product of the conditions under which it grows. The individual, the species, or the community may serve as an indicator, and the choice of the unit to be employed in a given case will depend partly upon the practical end in view, and partly upon the ecological data available. To give a concrete instance: the species Mertensia sibirica indicates the condition “deep shade” in the montane forest of Colorado. In using plant-communities as indicators Dr. Clements relies mainly upon the dominant species, so that in practice there appears to be no sharp distinction between specific and community indicators. His general classification of types of grazing-land, however, is based upon plant-communities, inasmuch as a uniform community of grass, weed, or browse is held to indicate suitability for cattle, sheep, or goats respectively, while a prairie or a grass-scrub mictium [i.e. a mixed community containing dominants both from grass- and from scrub-associations]1 or savannah denotes the advisability of mixed grazing by two or three kinds of animals. As an example of “individual” indicator-criteria, it is stated that ten “water-ecads” [i.e. habitat-forms corresponding to ten different degrees of water-supply] of Ranunculus sceleratus have been produced experimentally; plate 11 further shows photographs of [natural] shade, alpine, and “normal” ecads of Campanula rotundifoliaf Gentiana amarella, and Androsace septentrionalis.
Plant Indicators: The Relation of Plant Communities to Process and Practice.
By Frederic E. Clements. (Publication No. 290.) Pp. xvi + 388 + 92 plates. (Washington: The Carnegie Institution of Washington, 1920.) Price 7 dollars.
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D., M. Plant Indicators: The Relation of Plant Communities to Process and Practice . Nature 106, 304–305 (1920). https://doi.org/10.1038/106304a0
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DOI: https://doi.org/10.1038/106304a0
