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History of Ecological Sciences, Part 54: Succession, Community, and Continuum

2015; Ecological Society of America; Volume: 96; Issue: 3 Linguagem: Inglês

10.1890/0012-9623-96.3.426

2327-6096

Frank N. Egerton,

Earth Systems and Cosmic Evolution

Click here for all previous articles in the History of the Ecological Sciences series by F. N. Egerton Names and classifications of groups of organisms are based upon reality, but which reality? Like blind men encountering different parts of an elephant and announcing wildly different descriptions, ecologists (even if not blind) can see groups differently and then construct names and classifications differently. To some extent, it is a matter of convenience and convention—not a discovery comparable to finding that a water molecule consists of one atom of hydrogen combined with two atoms of oxygen. Agreements on names and definitions of groups of plants has been just slightly less difficult than getting agreement among blind men about what an elephant is like. Plant ecologists developed the ecological concepts of succession, community, and continuum, which later were expanded to include animals. An exception was Karl Möbius' concept of "biocönose" to describe animal communities on mudflats where oysters dominated (Möbius 1877, 1880:721–729), since plants on mudflats were inconspicuous phytoplankton. Conversely, the balance of nature concept had developed with only animals as examples, until Carl Linnaeus expanded that concept to include plants in his version of it, "oeconomia naturae" (Linnaeus 1749, 1755:39–129, Egerton 1973:335–337). Ordinary language divides our environment into forests, prairie, savanna, marsh, swamp, lake, seashore, and other entities, and sometimes subdivides these entities, such as into pine forest, oak forest, rain forest. Science moves beyond ordinary language when its concepts and objects are unnamed in ordinary language or need defining more precisely, requiring technical terms. However, the three ecological terms in the above title were all borrowed from ordinary language and given special meanings. Two early plant ecologists, Eugenius Warming (1895, 1909) and Frederic Clements (1916), coined a number of ecological terms, some of which continue in usage. An important aspect of the study of succession and community has been the names and terms involved. For the 1900s, Robert ("Mac") McIntosh provided clarification in "The Succession of Succession: a Lexical Chronology" (1999). Part 54 goes beyond my previous writings on the history of plant succession studies and formalizing plant ecology (Egerton 2009, 2013), and when touching upon topics previously discussed, I have new things to say. The concern here is not merely with who stated that a group of organisms form a distinct entity, but on how the investigator thought that entity was organized and functioned. The history of plant ecology is supported by surveys with bibliographic guides. Frederic Clements' chapter 2: "General Historical Summary," in his Plant Succession (1916:8–32) focused on studies published from 1685 to 1914. Narrower in scope, but including far more detail, was Rudy Becking's "The Zürich-Montpellier School of Phytosociology" (1957), which mentioned Humboldt, Schouw, and Heer, but focused upon studies published after 1850. Broader in scope than either Clements or Becking's surveys was Robert Whittaker's "Classification of Natural Communities" (1962), which mentioned a few works before 1850, but emphasized works published after 1850. David Shimwell's The Description and Classification of Vegetation 1971, focused upon works published after Grisebach's Die Vegetation der Erde 1872. Most of the 20 papers in Ordination and Classification of Communities, edited by Whittaker (1973), have historical discussions. The title of Maarel's "The Braun-Blanquet Approach in Perspective" (1975) seems to indicate a narrower scope than it has: its historical background has general interest. Malcolm Nicolson's articles on the history of plant ecology (1987, 1989, 1990, 1996, 2013), begin mainly with Willdenow, and are substantial contributions to topics discussed here. (Ecosystems will be discussed in part 59 of my history.) Michael Barbour, Jack Burk, and Wanna Pitts, Terrestrial Plant Ecology (edition 2, 1987:12–25) has a chapter on history, with illustrations, beginning with Willdenow. Paul Keddy wrote "Milestones in Ecological Thought—A Canon for Plant Ecology" (2005) that has echoes in his textbook, Plants and Vegetation: Origins, Processes, Consequences (2007), with historical discussions in chapter 2 and also in 17 "Enrichment Boxes" that are primarily historical, distributed throughout the chapters. Keddy was misled in Box 4.1, "The Discovery of Carnivorous Plants," by the lack of a historical introduction in Darwin's Insectivorous Plants (1875) into thinking that Darwin had discovered carnivorous plants. In fact, William Bartram (1739–1823) reported (1791) that Venus flytrap, pitcher plants, and sundew all catch insects (Egerton 2007c:261). Animal ecologist Frank Golley compiled a collection of 21 reprints (1901–1973) on Ecological Succession (Golley 1977), by both animal ecologists and plant ecologists, though the latter's reprints predominate. He divided his selection into five categories and provided an introduction for each category. We begin with early observations on bogs, because some bogs were known to have gradually come into existence or gone out of existence, and others had been drained to create dry land. Studies of bog vegetation, therefore, could potentially give rise to the botanical concept of succession. Gerrit/Gerard Boate (1604–1650), a Dutch physician living in London, did not use a technical vocabulary in Irelands Naturall History (London, 1652), when he divided the lands into three groups: moory or boggy heaths, dry heaths, and wet bogs (Gorham 1953:259–261, Egerton 2009:44). He did not choose between the terms "moory" and "boggy," and this kind of heath included "dry, or red bogs." But since he had originally divided lands into heaths and bogs, it is illogical to next subdivide one kind of heath into categories that included a kind of bog. Boate studied plants, but only categorized and described bogs and heaths. He discussed different kinds of vegetation without specifying what species of plants it included. Thirty-three years later, Boate's countryman, William King (1650–1729), Anglican clergyman in Dublin, wrote "Of the Bogs, and Loughs of Ireland" (1685) to assist in draining bogs. He divided bogs into quaking bogs and drier turf bogs, the latter being the same as red bogs. He thought that when seeds of bog-moss fell on dry land, it produced heath. Nevertheless. King gave "a clear and definite statement of succession, beginning with the mineral soil, passing through grassy quaking bogs, and growing into turf bog" (Gorham 1953:262). He saw (King 1685:950–951) that bogs are "generally higher than the land about them, and highest in the middle: the chief springs that cause them being commonly about the middle." A third Irishman, John Honohane, reported to the Royal Society of London (1697) that heavy rains caused a bog near Charleville, Limerick County, to slide down a slope and cover a meadow, in some areas 16 feet deep. A diagram—perhaps the first ever having ecological relevance—showed the direction of slide, from south to north (reproduced in Egerton 2009:46). Boate, King, and Honohane provided good general observations on bogs without observations on bog plant species. …plant shrubs and bushes which can break the force of the wind, diminish that of frost, and moderate the inclemency of the seasons. These bushes are the shelter which guards the young trees, and protects them against heat and cold. An area more or less covered with broom or heath is a forest half made; it may be ten years in advance of a prepared area. He continued, that after young trees "passed the first few years in the shade and shelter of the others, they quickly stretch up, and suppress all the surrounding plants" (Buffon 1742:238, from Clements). Carl Linnaeus (1707–1778), Buffon's Swedish rival, was foremost a botanist (Hagberg 1952, Blunt 1971, Morton 1981:259–276, Koerner 1999, Magnin-Gonze 2004:120–128, Nicolson 2013:96), but also a naturalist with broad interests (Egerton 2007a). He developed the first explicit version of ecology, named "oeconomia naturae" (Linnaeus 1749, [English, 1759, French, 1972], Egerton 1973:335–337, 2007a, 2012:see index). In that essay, which one of his students, I. Biberg, translated from Swedish into Latin as a doctoral dissertation, Linnaeus described plant succession from practically bare rock with lichens through a series of plant stages culminating in a forest, followed by death and decay of trees and the use of decaying wood by fungi and beetles to create a revolving cycle of nutrients. In another essay, which A. Hedenberg turned into Latin as a doctoral dissertation, Stationes Plantarum (1754), Linnaeus sought to distinguish between station (habitat) and habitation (range). On station he wrote, "the native places or stations of plants respect the country, climate, soil, and situation, nature of the ground, earth, and mould" (Linnaeus 1775:368), which is clear enough, but then he confused the issue by adding this definition to that of habitation: "along with latitude, altitude, and topography" (Linnaeus 1775:369–371). Linnaeus' list of stations of plants was: maritime or saline, marine, freshwater, damp regions, prairie, cultivated, rocky, sand, sterile soil, rubbish piles, forest, bushes and hedges, subterranean, mountain, parasitic, and saprophytic. Competition and avoidance of extinction were themes of Politia Naturae (Linnaeus 1760, [English, 1781, French, 1972]), which H. Wilcke turned into Latin as a doctoral dissertation. (Extirpate rather than extinguish is the term chosen by English translator Brand, but the context indicates that extinguish is what was intended: Linnaeus 1781:132.) Linnaeus realized that species produce more offspring than can survive, which produces "a war of all against all!" (Blair translation in Hagberg 1952:183). Despite that predicament, he believed the balance of nature was preserved, and he also explained how God had provided means of survival (a theme first addressed by Plato [Egerton 2001:96]) by what we call ecological diversity, as a way of reducing competition between species. Sweden had about 1300 plant species, but only about 50–100 live in any one place (Linnaeus 1781:133). All these changes occurred within a static system: Linnaeus assumed species were static until his later years, when he began to doubt their stability (Egerton 1973:335–337, 2007a). (a) Georges-Louis Leclerc, Comte de Buffon. By François-Hubert Drouais. Web. (b) Carl Linnaeus. Web. Swedish plant ecologist Einar du Rietz (1957) surveyed Linnaeus' observations and comments on peat bogs in some two dozen of his publications, 1742–1773, and also included those of some of his predecessor, students, and associates. This is Du Rietz's "Summary of Linnaean Contributions to Paludology" (du Rietz 1957:68): The statements about the habitats of various mire plants in Linnaeus's Flora Lapponica and Flora Svecica seem to be the first in botanical literature. Linnaeus seems to have been the first author to describe mire vegetation with lists of species. During the eighteenth century his descriptions were surpassed in exactitude and clearness only by his pupil [Pehr] Kalm, who published the first vegetation analyses with notes on the quantity of various species. Linnaeus's and Kalm's descriptions of bog vegetation were more correct and full of information than any others for nearly a century or more, i.e. at least until Grisebach (1845) published his descriptions of bog vegetation in NW Germany. In his Skånska Resa (1751) Linnaeus gave the first description of hummocks and hollows on a bog. Stenius (1742) published the first description of differences between fen and bog vegetation. The first lists, however, of species characteristic of fen (Paludes) and bog (Cespitosae Paludes) vegetation were given by Linnaeus 1751 in Philosophia Botanica. The domed shape of bogs was first described in print by King (1685 from Ireland). It was rediscovered by Linnaeus in Sweden and described by him in print 1747 and 1751. Similar observations were printed in Germany by Bansen 1753 and in Denmark by Borgen 1762. The first measurement of the convexity of a bog was printed by Carleson 1756 (from Sweden). The lagg surrounding a bog was first mentioned in literature by King 1685 (under the name of "the bounds of the bogs") from Ireland. It was rediscovered by Linnaeus in Sweden and described in his Skånska Resa 1751. The vegetable origin of peat was clearly stated by King (1685) and Linnaeus (1735). The part played by various plant species in peat formation was first elaborated by Linnaeus (1745b, 1747, 1749, 1750, 1751b, 1753c, 1755) and Kalm (1753). Different plant species were first mentioned as indicators of different habitats (in mires and elsewhere) by Linnaeus (1737, 1747, 1751a and b). By these contributions Linnaeus has well deserved an honorary position in the history of paludology as one of the chief founders of this science. Du Rietz expanded all of his above brief citations in his bibliography. Naked rocky places, on which nothing can grow, are, by the winds, covered with the seeds of Lichens, that by means of the accustomed showers in Harvest and Spring are induced to germinate. Here they grow, and the rock is spotted with their coloured frond. In time the winds and weather deposit small dust in the rough interstices of the rock, and even the decaying lichens leave a thin scurf. Much more of it Buell quoted, without realizing Linnaeus' influence. Nicolson (2013:96) quotes another relevant discussion. Alan Morton (1981:314) judged Willdenow's textbook as "the first attempt to explain the world distribution of species in a scientific manner." It is surprising that Clements (1916) did not discover Willdenow's contribution, since Willdenow's textbook exerted a strong influence on botany students. However, forest ecologist Stephen Spurr (1952) cited eight sources on forest succession, 1792–1860, only one of which Clements had cited, and several times I mention here succession studies which Clements cited in his book, but not in his historical summary (chapter 2). A Genevan natural philosopher living in London, Jean André Deluc (1727–1817), mainly studied geology, meteorology, and physics (Beckinsale 1971, Carozzi 1987:207–219). He discussed peat formation in a lengthy letter which he wrote in January 1806 to Rev. R. Rennie, for quotation in Rennie's Essays on the Natural History and Origin of Peat Moss (1807–1810); Deluc's letter shows he was "the keenest and most indefatigable of early students of peat-bogs…. He was probably the first to make use of the term succession, and certainly the first to use it with full recognition of its developmental significance" (Clements 1916:10). Rennie quoted from Deluc's letter at several places in his book, but most crucially on pages 137–141, which so impressed Clements that he included 1.5 pages of abridged quotation (Clements 1916:11–12) from Rennie's own quotation, on the six stages of succession when vegetation invades shallow lakes and convert them into peat bogs. An important source of plant ecology from the 1800s was phytogeography (Browne 1983, Lomolino et al. 2004), beginning with Alexander von Humboldt (1769–1859) and his colleague Aimé Bonpland (1773–1858), who spent five years (1799–1804) exploring Latin America (Nicolson 1987:174–186, 1996:290–292, 2013:96–97, Egerton 2009b, 2012:121–125). For present purposes, the most important of their sources is Essai sur la Géographie des Plantes (1807, also in German), in which some authors have credited Humboldt with using the term "association" to designate different kinds of vegetation. In fact, he was not trying to establish a vegetative terminology; he was merely using common language, as in: "Ces plantes associées sont plus communes dans les zones tempérées que sous les tropiques…" (Humboldt and Bonpland 1807:15). On the same page he also wrote: "D'autres plantes, réunies en société comme les fourmis et les abeilles…" Humboldt's important study on isothermal lines (Humboldt 1817; Robinson and Wallis 1967), which was translated into English (1820–22), was significant for phytogeography, if temperature could correlate with species distributions. (a) Karl Ludwig Willdenow. Web. (b) Jean André Deluc. Web. (a) Göram Wahlenberg. Web. (b) Joachim Frederick Schouw. Web. Humboldt became a famous scientist who exerted a strong influence upon others (Braun 1954:7–13 + 3 plates, Jahn 1965), some of whom followed him into plant geography. Among them were especially Scandinavian botanists. Göran Wahlenberg (1780–1851) studied medicine and botany at Uppsala University and spent his career there (Lindroth 1967, II:424–429, Eriksson 1976). His Scandinavian botanical explorations began in 1799, before Humboldt's influence touched him, and in 1811 he extended his explorations into central Europe, becoming friends with Willedenow when he visited Berlin. He published a series of floras of regions he explored (Pritzel 1872:336–337), with plant geography studies in their introductions. For his Flora Carpathorum Principalium 1814 he also inserted an early contour map of the Tatra Mountains (Szaflarski 1959). Danish lawyer-botanist Joachim Frederick Schouw (1789–1852) was another Humboldtian disciple (Christensen 1924–26, I:253–276, Sanders 1975b). In 1812, he accompanied Norwegian botanist Christian Smith on an expedition into Norway's mountains, where Schouw was impressed by the vegetation growing in definite zones up the sides of mountains (comparable to what Humboldt and Bonpland had published concerning South America in 1807). He wanted to study the causes, and in 1816 he earned a doctorate in botany at Copenhagen University, where he remained for the rest of his career. In 1822, Schouw was first to name plant associations by attaching the suffix -etum to the end of the genus name of the dominant species (Whittaker 1962:9, Nicholson 1996:293, 2013:97). Schouw explored Italy's vegetation and climate on two expeditions, in 1817–1819 (when he met his future wife) and in 1829–1830. After the first expedition, he published a survey of principles of phytogeography: Grundtraek till en aimindelig Plantegeographie (1822, viii + 466 pages, German, 1823, French, 1824). In 1839 he published Tableau du Climat et de la Végétation de l'Italie, volume 1. Malcolm Nicolson (1996:293) saw reference to volumes two and three, but was unable to locate either. In fact, Carl Christensen's bibliography for Schouw (1924–1926, II:165–179), with 96 titles, lists no volumes 2–3; instead, it lists a series of papers published in 1841–1849 on Italian plant geography. All the plants of a given country, [all those of a given place,] are at war one with another. The first which establish themselves by chance in a particular spot, tend, by the mere occupancy of space, to exclude other species—the greater choke the smaller, the longest livers replace those which last for a shorter period, the more prolific gradually make themselves masters of the ground, which species multiplying more slowly would otherwise fill. Candolle's "war one with another" echoes Linnaeus' Politia Naturae (quoted above), but Candolle first explained its dynamic significance. Perhaps he was influenced to pursue this thought by his familiarity with the French edition of Malthus' Essay on the Principle of Population (1809), translated by his former philosophy professor (Egerton 2010:29). Candolle actually met Malthus during his 1816 visit to England (Candolle 2004:318). English botanist William Hooker (1785–1865)—professor of botany at Glasgow (1820–40) and Director, Royal Botanic Gardens, Kew (1841–65) (Allan 1967, 1972, Pilet 1971)—wrote an article on plant geography for a geographical encyclopedia (1834); he followed rather closely Candolle's 1820 article (as Hooker acknowledged). Hooker distinguished range and habitat in this sentence: "Botanical geography is constituted by considering plants in relation to their habitation, region, or the country in which they grow, and in regard to their locality or particular station…" (Hooker 1834:228). The alternance or alternative succession in the reproduction of plants, especially when one forces them to live in societies, is a general law of nature, a condition essential to their conservation and development. This law applies equally to trees, shrubs, and undershrubs, controls the vegetation of social plants, of artificial and natural prairies, of annual, biennial, or perennial species living socially or even isolated. Later authors did cite this article, showing its influence (Drouin 1998:15–16). Sphagnum palustre and Dicranum glaucum are extremely social plants; they often cover the moors of the north with so thick and uniform a covering that seldom any other plant grows up amongst them, and the plains have thence a very dreary appearance. When Göettingen botany professor August Grisebach (1814–1879) used the term "formation" to distinguish different groups of vegetation (1838:160), he was not deliberately replacing Humboldt's term "association," since Humboldt had not established association as a technical term, though Schouw had (see above). Grisebach became a leading phytogeographer (Wagenitz 1972, Magnin-Gonze 2004:202, Egerton 2013:343–344), and two of his reports on advances in botanical geography, for the years 1842–1843 and 1844–1845, were translated into English (Grisebach 1846, 1849, 1977). He was best known for Die Vegetation der Erde nach ihrer Klamatischen Anordnung (1872), which included a colored map of world vegetation. …had a clear notion of the plant community as a type, its interrelations with the environment and the diagnostic value of plant species with a fidelity to one particular type of environment. Heer distinguished 30 "localities" (vegetation-site complexes that resemble our present-day ecosystems!). Each locality type is characterized by certain environmental characteristics, which may be found back in the type's name and characteristic species. It often can be recognized easily as a modern association…. Heer also paid attention to the performance of species, particularly their sociability, for which he used a ten-point scale. …these two moors [Vidnesdam, Lillemose] have developed during a period in which several forest vegetations have arisen and disappeared. The aspen forests may be regarded as preparatory to the pine and oak forests, which probably dominated the region for thousands of years, but have practically disappeared from the country to-day. While these forests, as well as the moor vegetations, belong in a definite time sequence, it is practically impossible to assign any absolute time for any or all of the layers. Grisebach's map of world vegetation (1872). From Magnin-Gonze 2004:202. (a) Oswald Heer. Web. (b) Henri Lecoq. Virville 1954:242. Thus began paleoecology, which eventually added a time dimension to vegetation studies. Assigning definite dates to peat layers became possible after World War II, using radioactive carbon decay measurements. French Professor and Director of the Jardin des Plantes of Clermont-Ferrand, Henri Lecoq (1802–1871), published an important study (1844) which "developed a quantitative measure which was essentially a combined cover-abundance estimation" (Maarael 1975:215). Darwin consulted it when writing his Origin of Species (Stauffer 1975:613, 671). Still more important was Lecoq's Étude sur la Géographie botanique de l'Europe (9 volumes, 1854–58). Maarel (1975:215) claimed that in 1854 Lecoq defined "association végétale" "along the lines Braun[-Blanquet] elaborated later, including the use of faithful species." Nicolson (2013:97) claimed that Lecoq (1854:58–90) "clarified the distinction between 'sociabilitié' —many plants of the same species living together—and 'association'—many plants of different species living together." School teacher Jules Thurmann (1804–1855) was born in a town in Alsace, France, and received his B.A. degree from the University of Strasbourg, but his widowed mother raised him in Porrentruy, Switzerland, and that remained his home town. He earned scientific recognition in both geology and botany from his publications, despite his death from cholera at middle age. Plant ecology historian Malcolm Nicolson quoted (in translation, Nicolson 2013:97) Thurmann's 1849 distinction between flora and vegetation: "A land's flora and its vegetation are two quite different things which should not be confused: the first means the numbers of the distinct plant species which one observes, the second their proportions and associations." Since Alexander von Humboldt published on both flora and vegetation, this distinction should have been clear around four decades earlier, but Thurmann and Nicolson nevertheless thought it worth reminding some readers of the distinction. Dr. Siegfried Reissek gave a talk in Vienna in September 1856 about his study of islands and vegetation formations in the Danube River—summarized in the October 1856 issue of Flora. Clements (1916:16–17) summarized Flora's summary of Reissek's article, and I summarize Clements' account. The islands grew from sand bars, and their vegetation emerged in a regular pattern. Willows—usually Salix purpurea—were first established, and their hummocks caught sand from water and helped islands grow. S. riparia and Myrica germanica came next, followed by Alnus incana, Populus alba, and Cornus sanguinea. After the latter three came Fraxinus excelsior, Ulmus campestris, Acer campestre, Quercus pedunculata, Pirus malus, P. communis….willows died off as soon as the trees of the second stage developed much shade…" (Clements 1916:17). The next year, Danish botanist-forester, and former student of Steenstrup, Christian Theodor Vaupell (1821–1862), published Bøgens indvandring i de Danske Skove (Invasion of Beech into Danish Forests, 1857). He had examined the fossil record of Danish forests and found no evidence of beech before recent times, and therefore he concluded it was a recent arrival from France and Germany as Denmark's forests became drier than before (Clements 1916:17, Christensen 1924–1926, I:472–492, II:288–292). Vaupell concluded that beech could displace formerly common birch and pine except in marshy or sterile soils. Section of Lillimose Moor, Denmark, showing central and marginal layers of an ecosere (Clements' term). After Steenstrup. From Clements 1916:15. Another isolated observer, Henry David Thoreau (1817–1862), a New England naturalist (Egerton 2011, 2012:151–156), spoke in 1860 to an agricultural society on "The Succession of Trees," which was published in the Transactions of the Middlesex Agricultural Society and also in a New York newspaper (Thoreau 1980). Clements' search of scientific literature did not uncover this talk. Thoreau saw that when pines were logged, oaks replaced them, and when oaks were logged, pines replaced them. He explained that pines could not replace cut pines because oak seedlings were already growing, and pine seedlings could not grow in shade. Squirrels buried more acorns in pine forests than they ever recovered in winter. Pine seeds blew annually into oak forests, and when oaks were cut, pine seedlings flourished in the sunlight. He also saw that birds eat cherries from trees and later expel the seeds elsewhere in their droppings. Not isolated was Austrian botanist Anton Kerner (1831–1898), whose Pflanzenleben der Donauländer (1863, English, 1951) is discussed by Nicolson (1996:297–298) and Egerton (2013:342–343). He used Grisebach's formation concept to describe the vegetation of the Danube valley: Juniper Formation, Oakwoods, Poplarwoods, Riverbank Forests, Swamps, Formations on Soils with Efforescent Salts, How a Swamp Becomes a Meadow, Draining of Swamps, Plant Formations of Dry Lands (Kerner 1951:ix). For the adjacent Carpathian Mountains he distinguished Deciduous Forests, Coniferous Forests, Elfinwood Formations, and Meadow Formations. For the adjacent Hercynian Mountains, he distinguished Beechwoods and Pinewoods, and Sprucewoods and Birchwoods. For adjacent Alps, including Achen and Oetz Valleys, he distinguished Evergreen Shrub Formations, Woodlands, and Alpine Meadows. In chapter 24, "The Genetical Relationships of Plant Formations," he discussed "Development of the Azalea Formation." Kerner's final chapter is "Plant Formations of the Oetz Valley" (Kerner 1951:206–227). It introduces some subdivisions not previously mentioned, although Oetz Valley was already discussed with Achen Valley. Some of these subdivisions are named formations, as "Calluna Formation," while others seem to be formations in content, if not in name, as "Alder Woods." Why did he chose this valley for more detailed treatment than the rest of his area? The answer seems to be: "No other Tyrolean valley can boast so rich a literature as this one" (Kerner 1951:206). Having more data from there to work with, he carried his analysis to finer detail than anyone did elsewhere. Clements (1916:484) cited Kerner's book, but did not discuss him as an early investigator of succession. Clements (1916:21–23) helpfully, but briefly, discussed several European contributors to plant succession observations during the 1870s and '80s, two of whom are also discussed here: Blytt and Hult. (Danish botanist Eugenius Warming was older than both Blytt and Hult, but his earlier work was not as relevant for plant ecology as his work during the 1890s, and so he is discussed below, after them and some others.) Norwegian botanist Axel Gudbrand Blytt (1843–1898) was son of Professor Matthias Nums Blytt (1789–1862) at Christiania University (now University of Oslo). In 1863, Norway bought Matthias Blytt's personal herbarium, and in 1865 Axel Blytt became conservator at the Christiania University Herbarium, and in 1880 he became a