Stations, types d'humus et groupements écologiques

Duchaufour, Philippe

doi:10.4267/2042/24296

Cited by 7 publications

(3 citation statements)

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“…niches are not a general feature of vegetation. In fact most ecologists find that they are, whether they are working in the deciduous forests, grasslands or weed communities of Europe (Ellenberg, 1954(Ellenberg, , 1963Duchaufour, 1960), the conifer forests and steppes of the western United States (Daubenmire, 1968 b, 1970), the forests of eastern Australia (Webb, Tracey, Williams & Lance, 1970) or those on tropical mountains (Wade & McVean, 1969;Grubb & Stevens, 1976; Grubb & Tanner, 1976). This grouping of species in habitat niches is very often accompanied by a striking conformation in life-form, leaf-form, etc., and clearly many physiological characteristics in the vegetative adult are similar in all the species within each group.…”

Section: I33mentioning

confidence: 99%

The Maintenance of Species‐richness in Plant Communities: The Importance of the Regeneration Niche

1977

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SUMMARY According to ‘Gause's hypothesis’ a corollary of the process of evolution by natural selection is that in a community at equilibrium every species must occupy a different niche. Many botanists have found this idea improbable because they have ignored the processes of regeneration in plant communities. Most plant communities are longer‐lived than their constituent individual plants. When an individual dies, it may or may not be replaced by an individual of the same species. It is this replacement stage which is all‐important to the argument presented. Several mechanisms not involving regeneration also contribute to the maintenance of species‐richness: differences in life‐form coupled with the inability of larger plants to exhaust or cut off all resources, also the development of dependence‐relationships, differences in phenology coupled with tolerance of suppression, fluctuations in the environment coupled with relatively small differences in competitive ability between many species, the ability of certain species‐pairs to form stable mixtures because of a balance of intraspecific competition against interspecific competition, the production of substances more toxic to the producer‐species than to the other species, differences in the primary limiting mineral nutrients or pore‐sizes in the soil for neighbouring plants of different soecies, and differences in the competitive abilities of species dependent on their physiological age coupled with the uneven‐age structure of many populations. The mechanisms listed above do not go far to explain the indefinite persistence in mixture of the many species in the most species‐rich communities known. In contrast there seem to be almost limitless possibilities for differences between species in their requirements for regeneration, i.e. the replacement of the individual plants of one generation by those of the next. This idea is illustrated for tree species and it is emphasized that foresters were the first by a wide margin to appreciate its importance. The processes involved in the successful invasion of a gap by a given plant species and some characters of the gap that may be important are summarized in Table 2. The definition of a plant's niche requires recognition of four components: the habitat niche, the life‐form niche, the phenological niche, and the regeneration niche. A brief account is given of the patterns of regeneration in different kinds of plant community to provide a background for studies of differentiation in the regeneration niche. All stages in the regeneration‐cycle are potentially important and examples of differentiation between species are given for each of the following stages: Production of viable seed (including the sub‐stages of flowering, pollination and seed‐set), dispersal, in space and time, germination, establishment, and further development of the immature plant. In the concluding discussion emphasis is placed on the following themes: the kinds of work needed in future to prove or disprove that different...

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Section: I33mentioning

confidence: 99%

The Maintenance of Species‐richness in Plant Communities: The Importance of the Regeneration Niche

1977

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“…Elle est de poids, si l'on sait combien l'humus est un intégrateur de tout un ensemble des propriétés du sol (DUCHAUFOUR, 1960). Parallèlement aux variations de rapports C/N ,un examen attentif des profils montre des différences marquées de structure au sein des horizons superficiels.…”

Section: -éTude Des Cations Et Anions Essentielsunclassified

Étude des relations sol-végétation en conditions d'hydromorphie dans une forêt de la plaine Lorraine

Becker¹

1972

Ann. Sci. forest.

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RÉSUMÉLe but essentiel du présent travail est l'étude des relations sol-végétation en milieu hydromorphe. Contrairement à la plupart des travaux similaires, qui sont des études statiques, nous nous sommes particulièrement attachés à l'aspect dynamique de la question, c'est-à-dire à l'évolution conjointe du sol et de la végétation sous l'influence de la dégradation d'origine humaine.L'étude a été menée dans cinq types de stations diversement dégradées (forêt feuillue), et caracté-risées par les cinq espèces herbacées qui marquent le plus le sous-bois : Molinia coerulea, Carex brizoïdes, Deschampsia coespitosa, Luzula albida, Poa chaixi.Le régime hydrique des sols correspondants a été particulièrement étudié : nappes perchées et pF. Puis, ont été analysés les divers facteurs écologiques pouvant induire les différences observées.Le problème des pseudogleys « fonctionnels » ou « non fonctionnels », sur fragipans, est largement débattu, et en particulier la question de la pédogénèse « actuelle » des horizons superficiels.Un certain nombre de mesures et d'observations plus strictement sylvicoles ont été effectuées. Les applications à la sylviculture de l'ensemble des résultats obtenus sont évoquées. £g

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“…On sait depuis les travaux de Duvigneaud (1946), puis de Duchaufour (1957( , 1960( ), de Gounot (1959 …”

Section: Introductionunclassified

Relations entre groupes écologiques et propriétés physico-chimiques des sols brunifiés des Vosges cristallines

Guillemin¹,

Rouiller²,

Bruckert³

1978

Ann. Sci. forest.

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Stations, types d'humus et groupements écologiques

Cited by 7 publications

References 0 publications

The Maintenance of Species‐richness in Plant Communities: The Importance of the Regeneration Niche

The Maintenance of Species‐richness in Plant Communities: The Importance of the Regeneration Niche

Étude des relations sol-végétation en conditions d'hydromorphie dans une forêt de la plaine Lorraine

Relations entre groupes écologiques et propriétés physico-chimiques des sols brunifiés des Vosges cristallines

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